Gypsum Wallboard

LIFE CYCLE ANALYSIS OFGYPSUM BOARD ANDASSOCIATED FINISHING PRODUCTS

Prepared by:

George J. Venta, P. Eng.VENTA, GLASER & ASSOCIATES

Ottawa, CanadaMarch 1997

DISCLAIMER

Although the ATHENATM Sustainable Materials Institute has done itsbest to ensure accurate and reliable information in this report, theInstitute does not warrant the accuracy thereof. If notified of anyerrors or omissions, the Institute will take reasonable steps to correctsuch errors or omissions.

COPYRIGHT

No part of this report may be reproduced in any form or by anymeans, electronic or mechanical, including photocopying, withoutwritten permission of ATHENATM Sustainable Materials Institute.

Text 1997 ATHENATM Sustainable Materials Institute

ATHENATM Sustainable Materials Institute112 Brock St. East, P.O. Box 189Merrickville, Ontario, Canada K0G 1N0Tel: 613-269-3795Fax: 613-269-3796E-mail: [email protected]

The AthenaTM Project:Gypsum Board and Associated Finishing Products

CONTENTS

PREFACE

ACKNOWLEDGMENTS

1.0 INTRODUCTION............................................................................................................. 1-11.1 Research Guidelines ................................................................................................... 1-11.2 Study Structure........................................................................................................... 1-21.3 Report Structure.......................................................................................................... 1-3

2.0 GYPSUM INDUSTRY - AN OVERVIEW..................................................................... 2-12.1 Industry Structure....................................................................................................... 2-12.1.1 Gypsum and Gypsum Board...................................................................................... 2-12.1.2 Gypsum Fiberboard.................................................................................................... 2-42.1.3 Gypsum Building Plasters.......................................................................................... 2-42.1.4 Joint Finishing Products............................................................................................. 2-52.2 Gypsum Board Manufacturing................................................................................... 2-62.2.1 Extraction 2-62.2.2 Calcination Plant......................................................................................................... 2-82.2.3 Gypsum Board Plant ................................................................................................ 2-112.2.4 Types of Gypsum Board Produced .......................................................................... 2-132.3 Gypsum Fiberboard.................................................................................................. 2-152.3.1 Gypsum Fiberboard Manufacturing ......................................................................... 2-152.3.2 Types of Gypsum Fiberboard Produced................................................................... 2-172.4 Gypsum Building Plasters........................................................................................ 2-172.4.1 Gypsum Building Plasters Manufacturing................................................................ 2-172.4.2 Types of Plasters Produced ...................................................................................... 2-192.5 Joint Finishing Products Manufacturing................................................................... 2-202.5.1 Ready Mix Joint Compound..................................................................................... 2-202.5.2 Dry (Setting) Joint Compound ................................................................................. 2-222.5.3 Products Statistics..................................................................................................... 2-232.5.4 Joint Paper Tape ....................................................................................................... 2-232.6 Gypsum Industry, Energy and Environment............................................................. 2-232.6.1 Energy Use and Efficiency ....................................................................................... 2-242.6.2 Atmospheric Emissions ............................................................................................ 2-252.6.3 Liquid Effluent.......................................................................................................... 2-262.6.4 Solid Waste .............................................................................................................. 2-262.6.5 Recycling 2-27

References 2-28


3.0 Raw Material Requirements and Transportation........................................................ 3-13.1 Raw Material Requirements - Gypsum Board ........................................................... 3-13.2 Raw Materials Transportation - Gypsum Board ......................................................... 3-33.3 Raw Material Requirements - Finishing Products...................................................... 3-63.4 Raw Materials Transportation - Joint Finishing Products........................................... 3-7

4.0 Energy Use - Gypsum Board ........................................................................................... 4-14.1 Raw Material Extraction and Transportation............................................................... 4-14.2 Gypsum Board Manufacturing................................................................................... 4-44.3 Finished Gypsum Board Transportation..................................................................... 4-74.4 Gypsum Board - Energy Summary ............................................................................ 4-94.5 Energy Use in Gypsum Fiberboard (GFB) Production............................................ 4-12

References 4-14

5.0 Energy Use - Finishing Products .................................................................................... 5-15.1 Joint Finishing Products Raw Material Extraction and Transportation ....................... 5-15.2 Joint Finishing Products Manufacturing..................................................................... 5-55.3 Joint Finishing Products Transportation..................................................................... 5-95.4 Joint Finishing Products - Energy Summary............................................................ 5-11

References 5-19

6.0 Atmospheric Emissions - Gypsum Board...................................................................... 6-16.1 Approach .................................................................................................................. 6-16.2 Atmospheric Emission Estimates................................................................................ 6-26.2.1 Raw Materials Extraction............................................................................................ 6-26.2.2 Raw Materials Transportation..................................................................................... 6-46.2.3 Gypsum Board Manufacturing................................................................................... 6-46.2.4 Finished Gypsum Board Transportation..................................................................... 6-76.3 Atmospheric Emissions Summary.............................................................................. 6-9

References 6-20

7.0 Atmospheric Emissions - Joint Finishing Products..................................................... 7-17.1 Atmospheric Emission Estimates................................................................................ 7-17.1.1 Raw Materials Extraction............................................................................................ 7-17.1.2 Raw Materials Transportation..................................................................................... 7-27.1.3 Joint Finishing Products Manufacturing..................................................................... 7-57.1.4 Finished Associated Products Transportation............................................................. 7-77.2 Joint Finishing Products Atmospheric Emissions - Summary.................................... 7-9

References 7-19


8.0 Liquid Effluents ............................................................................................................... 8-18.1 Liquid Effluent Estimates - Gypsum Board................................................................ 8-18.1.1 Raw Materials Extraction............................................................................................ 8-18.1.2 Gypsum Board Manufacturing................................................................................... 8-38.2 Liquid Effluent - Gypsum Board Summary................................................................ 8-68.3 Liquid Effluent Estimates - Finishing Products .......................................................... 8-68.3.1 Joint Compounds........................................................................................................ 8-68.3.2 Joint Paper Tape ......................................................................................................... 8-6

References 8-13

9.0 Solid Wastes .................................................................................................................. 9-19.1 Solid Wastes Estimates - Gypsum Board................................................................... 9-19.1.2 Raw Materials Extraction............................................................................................ 9-19.1.2 Gypsum Board Manufacturing................................................................................... 9-29.1.3 Total Solid Waste Due to Gypsum Board Production................................................ 9-29.2 The Use of Wastes in Gypsum Board Processing...................................................... 9-39.3 Solid Wastes Estimates - Finishing Products ............................................................. 9-5

References 9-5

Preface

This report was commissioned as part of the continuing program to expand the knowledge base ofthe ATHENA project. The project was initiated in 1990 by Forintek Canada Corp., with the supportof Natural Resources Canada, under the name Building Materials in the Context of SustainableDevelopment. Work on the ATHENATM project is now being carried forward by the ATHENATM

Sustainable Materials Institute, a not-for-profit organization dedicated to helping the buildingcommunity meet the environmental challenges of the future.

The ultimate goal is to foster sustainable development by encouraging selection of the material mixthat will minimize a building’s life cycle environmental impact. To achieve that goal the Institute isdeveloping ATHENA , a systems model for assessing the relative life cycle environmentalimplications of alternative building or assembly designs. Intended for use by building designers,researchers and policy analysts, ATHENA is a decision support tool which complements andaugments other decision support tools like costing models. It provides a wealth of information tohelp users understand the environmental implications of different material mixes or other designchanges in all or part of a building.

The ATHENATM Institute is continuing the practice of publishing all individual researchreports and major progress reports to make the process as transparent as possible and toensure the research and results are fully accessible. To ensure continuity, previouslypublished reports are being reissued as part of the Institute series.

Institute studies and publications fall into two general categories: investigative or exploratorystudies intended to further general understanding of life cycle assessment as it applies to buildingmaterials and buildings; and individual life cycle inventory studies which deal with specificindustries, product groups or building life cycles stages. All studies in this latter category arefirmly grounded on the principles and practices of life cycle assessment (LCA), and follow ourpublished Research Guidelines which define boundary or scope conditions and ensure equaltreatment of all building materials and products in terms of assumptions, research decisions,estimating methods and other aspects of the work. The integration of all inventory data is a primaryfunction of ATHENA itself. ATHENA also generates various composite measures that can bebest described as environmental impact indicators, a step toward the ultimate LCA goal ofdeveloping true measures of impacts on human and ecosystem health.

We believe this report and others in the series will be of value to people concerned with theenvironmental implications and sustainability of our built environment. But we caution thatindividual industry life cycle study reports may not be entirely stand-alone documents in the sensethat they tell the whole story about an individual set of products. For example, the report onconcrete notes how much steel is used for reinforcing various products, but the life cycle inventorydata for those steel products is included in the reports dealing with integrated and mini-mill steelproduction. There are also transportation and energy production and distribution aspects that arecommon to many different building projects, and are therefore handled separately withinATHENATM.

Please contact us at the address shown on the Disclaimer/Copyright page at the front of this reportfor more information about the ATHENATM Sustainable Materials Institute, or for other reports in theseries.


ACKNOWLEDGMENTS

Forintek Canada Corp. would like to acknowledge NaturalResources Canada for its funding contribution to theATHENATM Sustainable Materials Project. In addition,Forintek would like to thank all of the research alliancemembers for their timely work, their assistance and theirenthusiasm for the project.

The life cycle study described in this report was carried out by VENTA, GLASER & ASSOCIATES

under Forintek Canada Corp. Contract. The author gratefully acknowledges their support. Specialthanks go to the managers of the ATHENATM Project, Wayne Trusty of Wayne B. Trusty &Associates Limited and Jamie Meil of JKM Associates for their enthusiasm and guidance. Wewish to thank all the major gypsum companies in Canada - CGC INC., DOMTAR GYPSUM, andWESTROC INDUSTRIES LTD. - for their trust and cooperation in providing the necessary data input.Thanks are especially extended to the following individuals for their valuable contributions:

Brian Colbert W.R. Grace & Co. of Canada Ltd.Robert Daly Ontario HydroGerry Harlos Domtar GypsumMike Hunter CGC Inc.A. Marchand The Beaver Wood Fibre Company Ltd.David Shanahan Westroc Industries Ltd.Francis Vrillaud Domtar GypsumRick Weber CGC Inc.

We also want to acknowledge the following provincial and regional authorities and theirrepresentatives for their input:

Michel de Spot Greater Vancouver Regional DistrictSerge Goulet Quebec MOE&FBernard Matlock Nova Scotia DOEDon Murray New Brunswick DOEJean Van Dusen Manitoba EnvironmentSimon Wong Ontario MOEE

Finally, we want to express our thanks to the GYPSUM ASSOCIATION, to Bob Wessel and JerryWalker, for their support, willingness to review this study and to provide us with their comments.

The AthenaTM Project:Gypsum Board and Associated Finishing Products 1-1

LIFE CYCLE ANALYSIS OF GYPSUM BOARDAND ASSOCIATED FINISHING PRODUCTS

1.0 INTRODUCTION

This report presents cradle to gate life cycle inventory estimates for gypsum board and associatedfinishing products, and explains how the estimates were developed. The work was commissionedby the ATHENATM project as part of the continuing series of life cycle studies being done to supportthe ATHENATM environmental decision support tool described in the Preface.

ATHENATM relies on life cycle inventory databases, termed unit factors, which include estimates ofraw material, energy and water inputs as well as atmospheric emissions, liquid effluents and solidwastes outputs per unit of product. The estimates encompass production activities from rawmaterials extraction (e.g. gypsum quarrying) through product manufacturing, including relatedtransportation. We have also provided estimates of typical or average transportation modes anddistances for the distribution of finished products from relevant manufacturing facilities to the sixregions covered by the computer model.

The estimates presented in this report were developed by Venta, Glaser & Associates with theassistance and cooperation of the Gypsum Association and its member companies.

1.1 RESEARCH GUIDELINES

To ensure consistent and compatible approaches by the different alliance members, all estimates hadto be prepared in accordance with a set of research guidelines first issued in October 1992 andsubsequently revised as work proceeded. This research protocol defined information requirementsand procedures for the study, such as the following:

• the specific building products;• the content of general and detailed industry descriptions;• the specific energy forms, emissions and effluents of potential interest;• the treatment of secondary building components and assemblies;• preferred data types and sources (e.g. actual industry data and data from

process studies);• the analysis scope, including system boundaries and limits and the level of

detail of the analysis;• geographic divisions;


• transportation factors to be included when estimating transportation energy use; and

• a set of standard conventions for dealing with such aspects as non-domestic production, process feedstocks, in-plant recycling and multiple products.

In addition, the research guidelines provided a set of conversion factors and tables of standardfactors for calculating energy contents and emissions by fuel type.

The analysis limits established for the project in the guidelines are similar to a Level II analysis forenergy studies as determined by the International Federation of Institutes of Advanced Studies.These limits typically capture about 90% to 95% of the full impacts of an industry.

The life cycle analysis framework, additional unit factors and related impact studies are discussed indetail in the Phase III Summary Report. The Research Guidelines are available under separatecover as part of the full set of project reports and we have not, in this report, duplicated that materialby explaining the rationale for all steps in the research and calculation process. For example, theResearch Guidelines require that empty backhauls be included when calculating transportationenergy use in certain circumstances. Our calculations therefore show the addition of such backhaulmileages without explaining why backhauls should be included. However, we have provided fullexplanations wherever our calculations do not conform to the guidelines because of data limitationsor for other reasons.

1.2 STUDY STRUCTURE

The systems model requires unit factors for the following specific gypsum boards and associatedfinishing products:

• 1/2" regular gypsum board,• 5/8" regular gypsum board,• 1/2" Type X (fire-resistant) gypsum board,• 5/8"" Type X (fire-resistant) gypsum board,• 1/2" moisture-resistant (MR) gypsum board,• 5/8" moisture-resistant (MR) gypsum board,• 5/16" mobile home gypsum board,• 1" shaftliner board,• 1/2" gypsum fiberboard (GFB),• 5/8" gypsum fiberboard (GFB),• drying type ready-mixed joint compound,• setting type dry joint compound, and• paper joint tape.


Gypsum board and associated jointing products are essential building materials for the Canadianresidential, commercial, industrial and institutional housing industries, and we had to fully analyzethe gypsum industry before developing unit factors for these products. That fact dictated how ourstudy was structured.

Unit factor estimates for the Canadian gypsum board industry were developed and are expressed interms of material inputs or waste outputs per unit of product. Similar estimates were thendeveloped for the jointing materials required to apply and finish gypsum board-based systems.These two sets of factors have to be combined in the ATHENATM computer model to develop thedesired estimates for a specific board application.

The analysis procedures and calculations are described in detail in the relevant sections of thisreport. The key point at this stage is that the study was structured as two separate, but obviouslyrelated, analysis streams — one for gypsum board and one for the jointing products of interest.

1.3 REPORT STRUCTURE

The arrangement of this report basically parallels the study structure. Section 2 of the reportprovides the background information regarding the industry within the framework of the Canadianeconomy. It discusses in some detail the industry structure, manufacturing processes, types ofgypsum board and associated products manufactured and used in Canada. The fact that gypsumboard is a composite material, and that its production consists of three distinct and separatemanufacturing steps [i.e. partial dehydration (calcination) of gypsum to stucco, paper (to be used asgypsum board facings) manufacturing, and production of gypsum board itself through combinationof stucco and paper] affects the discussion of the manufacturing process. Section 2 also introducesthe major aspects of the industry with respect to energy consumption and environment, andhighlights some of the achievements in this area. Sections 3 through 9 deal with various aspects ofraw material balances, energy consumption and environmental issues of the production of thegypsum board as well as the associated joint finishing products.

As indicated below, the basic progression in each part involves an overview section followed by aseries of sections dealing with each of the environmental impact areas (e.g. raw material use, energyuse, emissions, etc.) Results are presented to show regional variations and, as necessary, byproduction stage (e.g. resource extraction, raw materials transportation, manufacturing and finishedproducts transportation).

The following regional breakdown was followed in the study:

• West (British Columbia, Alberta and Saskatchewan);• Central (Manitoba and Ontario); and• East (Quebec and Atlantic Provinces).


The Research Guidelines prefer separate information for the West Coast and Prairie regions.However, we had to combine these two regions into one, West region, in order to maintain theconfidentiality of data provided by manufacturers: there are only two plants on the West Coast andtwo plants on the Prairies.

The report is organized as follows:

Section 2 presents an overview profile of the gypsum industry in Canada,including a description of the different production processes, theindustry structure in geographic, process and capacity terms, and thegeneral nature of resource and energy use, emissions and otherwastes for both the gypsum board and the associated joint finishingmaterials.

Section 3 details raw material use by the gypsum board industry on a regionalbasis, and discusses raw material transportation requirements.

Section 4 describes the gypsum board energy use analysis and presents theresults, with sub-divisions by region and by stage of production.

Section 5 describes the energy use analysis for associated finishing productsand presents the results, with sub-divisions by region and by stage ofproduction.

Section 6 deals with atmospheric emissions associated with gypsum boardproduction on a regional basis by production stage, including theanalysis method and results.

Section 7 deals with atmospheric emissions generated by production ofassociated finishing products on a regional basis by productionstage, including the analysis method and results.

Section 8 focuses on liquid effluents associated with production of gypsumboard and associated finishing products.

Section 9 deals with solid wastes generated by production of gypsum boardand associated finishing products.

At the end of each section, a summary of all the developed unit factor estimates is presented.


2.0 GYPSUM INDUSTRY - AN OVERVIEW

This section provides an overview of the gypsum board and associated finishing products industryin Canada. It provides basic information on the structure, size, production volumes andgeographical distribution of the industry, and its position within the framework of the Canadianminerals as well as construction industries.

The basic manufacturing processes for the production of gypsum board, joint compounds, and jointpaper tape, are shown and described. Related energy use and efficiency issues, as well asemissions, effluents and waste outputs are also briefly discussed as an introduction to a moredetailed description of these aspects and the development of the appropriate unit factors insubsequent sections.

2.1 INDUSTRY STRUCTURE

2.1.1 Gypsum and Gypsum Board

Canada has abundant sources of natural gypsum, a relatively soft rock-like mineral that wasdeposited in ancient seas. Chemically, gypsum is calcium sulfate dihydrate (CaSO4•2H2O) andCanada is the third largest producer of crude gypsum in the world, after the U.S.A. and China,generating about 7.3% of the total annual production of this mineral. In 1994, Canadian shipmentsof crude gypsum were about 8,110,000 t valued at over $91-million.1 A substantial portion of thisproduction, over 70%, is exported, mainly to the U.S. markets. In Canada, almost 2.5 milliontonnes of gypsum were used in 1994. Over 70% of gypsum quarried or mined in Canada comesfrom Nova Scotia, with the rest originating in Ontario, Manitoba and British Columbia. On theWest Coast, some gypsum rock is imported from Domtar Gypsum’s co-owned San Marcos Islanddeposits in the Baja California area of Mexico.

In the U.S., and we assume in Canada as well, about 71 to 75% of gypsum is used in theproduction of gypsum board, about 2 to 3% for building and industrial plasters, about 14 to 17% inthe cement industry, where it is interground with clinker to control cement set, and the remaining9% in agriculture.2

While natural gypsum represents at this time the overwhelming portion of the Canadian gypsumsupply, chemical gypsums are starting to be considered as options to natural gypsum. Syntheticgypsums are most often a by-product of flue gas scrubbing (desulfurization), although co-productsof various chemical processes, such as titanium dioxide (TiO2) gypsum, are possible candidates forgypsum board production as well.

Synthetic gypsums’ availability and use are new to Canada. Although chemical gypsums have beenused overseas for some time, the abundant sources of quality gypsum on this continent were notconducive to a similar practice in Canada or the U.S.A.3 In 1995 a major gypsum board operation,Westroc’s Mississauga plant, switched from gypsum rock to FGD gypsum, a by-product of fluegas desulfurization, from Ontario Hydro’s Lambton Thermal Power Generating Station. This was


the first such conversion in Canada. It is reported that Westroc’s Montreal plant is alsosupplementing natural gypsum with FGD by-product gypsum originating from the NYSEG’s(New York State Electric & Gas Corporation) operations in upper New York state. Further, about230,000 tonnes of marketable FGD gypsum/year will be available shortly from New BrunswickPower Corporation’s Belledune Generating Station 3. Recently CGC started to use some TiO2 by-product gypsum in its Montreal plant. It is estimated that up to 8-10% of Canadian gypsum boardcapacity was poised to use non-traditional, by-product sources of gypsum beginning in early 1996.

Within the last fifty years, gypsum board, also popularly known as drywall or plasterboard, hasbecome the dominant product for finishing interior walls and ceilings in residential, commercial andinstitutional buildings. More than 95% of interior walls in Canada and the U.S.A. are finishedusing this inexpensive building material.3 In 1994, more than 267-million m2 of gypsum boardwere produced in Canada.4 Quoting the Gypsum Association, Canadian board capacity at the 1994year end was 345-million m2, which would indicate 77% capacity utilization.2 The total annualNorth American gypsum board production capacity is 2.7 x 109 m2, or 9.8 m2 per capita, thehighest in the world.5,2

In Canada, gypsum board is produced in all provinces with the exception of Prince Edward Islandand Saskatchewan. There are three major companies producing gypsum board: CGC Inc., DomtarGypsum, and Westroc Industries Limited. CGC Inc. is about 75% owned by USG Corporation,the largest gypsum products manufacturer in the world, while Westroc is a part of the BPB familyof companies, the second largest gypsum products producer in the world. Domtar Inc. recentlyannounced an agreement to sell its gypsum division to Georgia-Pacific Corporation.6 Typically, asubstantial share of Canadian board production, especially from the Quebec and Ontario plants, isexported to New England, New York and Michigan, with some occasional exports to countries likeDenmark, Czech Republic, Cuba, Hong Kong, and Brazil as well as to the Middle East.

Most of the gypsum board manufacturers are large, vertically integrated operations mining orquarrying their own gypsum rock, and producing not only a range of board products, but most ofthe associated joint finishing materials as well. While gypsum products manufacturers also oftenown and operate their own paper mills in the U.S., this is not the case in Canada. Facing papers forgypsum board are made in Canada by only two independent producers, Beaver Wood Fibre Co.’splant in Thorold, ON, and CPL Paperboard Ltd. in Burnaby, B.C. The rest of the paper needs ofthe Canadian gypsum board manufacturers are supplied from the U.S.A.

Table 2.1 shows the gypsum mining and gypsum board manufacturing operations, and theirlocations.


TABLE 2.1: GYPSUM MINING AND GYPSUM PRODUCTS MANUFACTURING OPERATIONS, 1994

Company Location Operation

NewfoundlandDomtar Inc. Flat Bay Open-pit mining, closed in 1994Atlantic Gypsum Corner Brook Gypsum board manufactureNova ScotiaDomtar Inc. McKay Settlement Open-pit miningDomtar Inc. Windsor Plaster manufactureFundy Gypsum Company Limited Wentworth and Miller Creek Open-pit miningGeorgia-Pacific Corporation Sugar Camp Open-pit miningLittle Narrows Gypsum Company Ltd. Little Narrows Open-pit miningNational Gypsum (Canada) Ltd. Milford Open-pit miningLouisiana-Pacific Corporation Port Hawkesbury Gypsum fiberboard manufactureNew BrunswickWestroc Industries Limited McAdam Gypsum board manufactureQuebecCGC Inc. Montreal Gypsum board manufactureCGC Inc. St. Jerome Gypsum board manufactureDomtar Inc. Montreal Distribution terminal onlyWestroc Industries Limited Montreal Gypsum board manufactureOntarioCGC Inc. Hagersville Underground mining and gypsum board

manufactureDomtar Inc. Caledonia Underground mining and gypsum board

manufactureWestroc Industries Limited Drumbo Underground mining, closed in 1995Westroc Industries Limited Mississauga Gypsum board manufactureManitobaDomtar Inc. Amaranth Open-pit miningDomtar Inc. Winnipeg Gypsum board manufactureWestroc Industries Limited Amaranth Open-pit miningWestroc Industries Limited Winnipeg Gypsum board manufactureAlbertaDomtar Inc. Edmonton Gypsum board manufactureWestroc Industries Limited Calgary Gypsum board manufactureBritish ColumbiaDomtar Inc. Canal Flats Open-pit miningDomtar Inc. Vancouver Gypsum products manufactureWestroc Industries Limited Windermere Open-pit miningWestroc Industries Limited Vancouver Gypsum products manufacture

Source: Adapted from Ref. (1)


2.1.2 Gypsum Fiberboard

Gypsum fiberboard (GFB) is a product that is new to the North American markets, beingintroduced here in about 1990. GFB products were developed over the last 20 years in Germany,where the product has been quite successful, capturing about 20 to 25% of the total gypsum boardmarket. There are a number of competing processing technologies. What all of these have incommon is the fact that the finished board is “paperless”, that is, it does not have any paper facingsas does the conventional gypsum board. Instead GFB consists of about 18% ground wastenewsprint/magazine fibers uniformly dispersed throughout the gypsum matrix. It is this recycledpaper fiber that provides the reinforcement of the matrix instead of the paper skins.17

The only North American GFB operating facility is Louisiana-Pacific’s plant in Port Hawkesbury,NS. The rated annual capacity of the plant using Carl Schenck’s AG technology is about 23-million m2 per year, representing about 6.7% of the total gypsum board capacity. The plant’sstrategic location allows shipping along the Eastern seaboard of the U.S. Market penetration inCanada appears to be limited at this time, and is perhaps more successful in non-traditional areas(for gypsum-based boards) such as 3/8" thick 4' x 4' sheets of floor underlayment than incompetition with conventional gypsum board for wall and ceiling applications. L-P’s literature19

(October 1993) gives production volume as 6.5-million m2, which would indicate capacityutilization of only 28% at that time. The corresponding share of L-P’s FiberBond® GFB would beabout 2.8% of the total Canadian gypsum board production and, as the bulk of the finished board isbeing shipped to U.S. destinations, their market share in Canada is expected to be even smaller.

2.1.3 Gypsum Building Plasters

Gypsum building plasters applied over lath were used for centuries to finish interior wall andceiling surfaces. However, about 30 or 40 years ago, gypsum board replaced plaster as the premierwall-cladding material due to its ease of application and economy factors. Plastering of the wallsurfaces requires trained, experienced workers. Although plaster can provide a superior wallsurface, these days only a fraction of walls are finished that way. Building plasters have beenlargely replaced by more economical and easier-to-apply gypsum board systems.

Building plasters are formulated products that may contain, in addition to calcined gypsum (stucco),hydrated lime, talc, clay, various chemical additives and admixtures to control product set, handlingand application characteristics. Some building plasters may also contain various aggregates:materials such as sand, woodfiber, vermiculite or perlite. While some building plasters are appliedover gypsum lath or metal lath, more often veneer plasters are used in thin (1/16" to 3/32") coatapplications over a special type of gypsum board for veneer plasters. One-coat as well as two-coat(base and finish coats) systems are available.


2.1.4 Joint Finishing Products

Joint finishing products are an integral part of gypsum board systems. Their role is to finish thejoint between the individual sheets of gypsum board in such a manner that even under criticallighting the whole wall (or ceiling) gives an impression of a monolithic surface. Typically a paperjoint tape embedded in joint compound is used to “bridge” the joint. (In a relatively newdevelopment, some glass mesh tape has been used for the same purpose, especially by the "do-it-yourself" market.) Additional application(s) of joint compounds are required to provide a smooth,uniform joint treatment.

Joint compounds are highly formulated products consisting of 8 to 12 different raw materials toensure a joint compound with the right application, performance and appearance characteristics.Although the basic composition of each type of compound is common to all brands within that type,different additives and admixtures make these brand formulations proprietary. Basically, there aretwo types of joint compounds on the market,

• drying compounds, and• setting compounds.

Drying compounds are usually calcium carbonate-based. The overwhelming majority are producedas “ready mix”, compounded with other ingredients, such as talc, mica, thickeners, resin/latex,perlite, preservatives, and water to produce creamy, easily spreadable paste. These compoundsshrink upon drying, and there is, therefore, a need for further applications of the compound and“feathering” of the joint, with proper drying and sanding in between the applications, to obtain asatisfactory joint. Ready mix joint compound is usually applied in three coats. Gypsum boardmanufacturers specify about 67.4 kg of joint compound per 100 m2 of board (138 lb/MSF).20

(Similarly about 98 m of joint tape is used for 100 m2 of board (300'/MSF).) These amountsalready account for small joint compounds and joint tape wastes during their application.

Setting compounds are usually stucco-based and, therefore, come only in dry form. They aremixed with water only just prior to their application and, depending on their formulation, theytypically then have a 45- or 90-minute “pot” life. As the hardening of these compounds is achemical reaction rather than a physical one (drying), their shrinkage is substantially lower than thatof the ready mix joint compounds. Due to their convenience, ready mix joint compounds are muchmore popular than the dry powder materials. According to Statistics Canada, 131,844 tonnes ofready mix compounds and 11,877 tonnes of dry powder compounds were produced in 1994.4

Joint compounds are produced and marketed by all three major gypsum board manufacturers, CGCInc., Domtar Gypsum, and Westroc Industries Ltd. Louisiana-Pacific offers fiber filled ready mixcompound compatible with their gypsum fiberboard. There are also a number of independent jointcompounds producers, among them Synkoloid in Vancouver and Edmonton, Ontario Gypsum andBondex in Toronto, Rayproc in Montreal, and Maritime Gypsum in New Brunswick.


2.2 GYPSUM BOARD MANUFACTURING

Gypsum board is manufactured in a two step process. In the first step finely crushed and groundgypsum, calcium sulfate dihydrate (CaSO4•2H2O), is heated and partially dehydrated (calcined) tocalcium sulfate hemihydrate (CaSO4•1/2H2O), called stucco in the industry, also popularly knownas “Plaster of Paris”. A unique characteristic of stucco is that when it is mixed with the properamount of water, it forms a smooth plastic mass which can be molded into any desired shape.When the hardening has been completed, the mass has been chemically restored to its rock-likestate. This characteristic has also been used in the development and production of gypsum board.In the second step of the manufacturing process stucco is mixed with a number of additives, foamand an excess amount of water to prepare gypsum slurry which is extruded on a fast moving,continuous board production line between two layers of special gypsum paper. “Raw” gypsumboard is then allowed to fully hydrate - calcium sulfate hemihydrate is converted back to dihydrate -before it is cut to the desired size and before it enters a “gypsum kiln”, where at elevatedtemperatures the excess water is driven off. The gypsum board is then stacked, ready to beshipped. The process is described in literature from a number of gypsum board manufacturers aswell as equipment suppliers.7-12

The basic manufacturing steps are depicted in Figure 2.1 and summarized below:

2.2.1 Extraction

Rock mining/quarrying

Gypsum rock is open pit quarried or (underground) mined, generally by drilling and blasting, thenmoved to a primary crusher close to the quarry/mine site. The primary deposits of high qualitygypsum in Canada are found in the Atlantic provinces, where open-pit quarrying is used. Thequarry process begins by first removing the earth over the deposit. Then gypsum rock is drilledand blasted loose to be carried to the processing plant where it is crushed and screened. The largestquarry in the world, National Gypsum's Milford NS operation produces up to 4.5-million tonnes ofgypsum a year. Quarrying is also a primary extraction technique used in Manitoba and BritishColumbia.

In south-western Ontario, gypsum is mined in underground mines. There, gypsum lies about 80 to100 feet below ground level. The deposits lie in flat beds approximately 48" thick, interlayed withlimestone. Either mine shafts driven straight into the ground or long sloping tunnels leadingthrough the overburden of soil, clay and limestone rock are used to access the gypsum strata. Fromthere extend “streets”, separated from each other by pillars of rock left to support the roof of themine. Domtar’s #3 mine in Caledonia recently went to a continuous mining technology usingelectrically powered machines to cut the rock in place, thus eliminating the use of any explosives.Front-end loaders, diesel-powered shuttle cars, trucks, hoists and conveyor belts are all used invarious quarrying and mining operations.


gypsum rock(mined or quarried)

by-productgypsum

(FGD or TiO2)

or

crusher screen

hammer mill

gypsumbin

continuouskettle

calciner

screenRaymond mill

stuccobin

additives

facepaper

backpaper

pin mixer

H2O

boardknife

stacking,bundling

gypsum board to warehouse & shipping

board kiln

Fig. 2.1 Flow diagram of a typical gypsum board plant using continuous kettle calcination (adapted from Refs. 7, 8, 9).


Primary crushing

In the primary crusher, gypsum rock is reduced to approximately 2" - 5" or less in size. From herethe crushed rock can be sent to secondary crushing and conveyed directly to the mill, it can bestockpiled, or, as is the situation in most cases because quarry and the production facilities areusually not in the same location, it can be shipped by ship, rail or truck to the manufacturing plant.In Canada only CGC’s Hagersville plant and Domtar’s Caledonia one are located directly on themine.

2.2.2 Calcination Plant

Secondary crushing, drying, milling

After primary crushing, gypsum rock may be sent through the dryers. Normally gypsum rock has1-3% free moisture content (quarry water). At this moisture content level, it may by-pass the dryer.However, if the moisture content is higher (typically up to 10%), as is often the case if the materialhas been stockpiled outside, some drying in directly heated rotary dryers is needed in order toreduce moisture to below the 3% level. Secondary crushers, typically hammermills, reduce the rockfurther to about 1" in diameter. Baghouses are preferred to collect fine particulate matter, althoughsome plants may use electrostatic precipitators or cyclones. These operations usually take place atthe plant site.

In most of the processes the crushed rock is fed to the roller or other type of mill, where its size isfurther reduced so that 90% will pass through a 150 µm sieve. The resulting form of gypsum iscalled landplaster, referring to one of its possible uses. In some processes (Imp Mills, for example)calcination and grinding can be accomplished simultaneously and, in such a case, no prior grindingis required. Rock drying/grinding consumes ~6% of the total energy required to produce gypsumboard (not counting energy needed to produce paper skins for the board).13

Other sources of gypsum

Quarried or mined gypsum represents the bulk of the gypsum supply and consumption. However,there are two additional sources of raw gypsum that can be used: waste gypsum (board) andindustrial by-product gypsum.

The term waste gypsum is understood to mean internally generated plant waste and, more recently,also new construction waste collected and brought back to the manufacturing facilities, primarily inthe Vancouver and Toronto metropolitan areas. (No gypsum plants accept any demolition wastedue to possible contamination.) When waste gypsum board is used, it has to be broken down,chopped and crushed. A variety of different equipment and techniques are used: Norba crushersappear to be the most efficient and favoured ones. In some cases a portion of paper / paper fibers isremoved or screened from the waste gypsum stream. Typically, the gypsum board plants thatrecycle waste gypsum board use up to about 20% waste in their gypsum stream. Unless preventedby some technical reasons, producers like to do so, as it makes not only environmental, but alsoeconomic sense.


Use of by-product, chemical gypsum is new to the North American continent. In the U.S.,by-product gypsum represented only 3.6% of the total gypsum supply in 1994.2 In Canada,Westroc is the first gypsum board producer to use FGD gypsum on any significant scale startingin 1995.

Flue gas desulfurization (FGD) gypsumGrowing awareness of the environmental damage caused by SO2 emissions and the resulting acidrain, followed by legislative actions, spurred research and development of a large number of FGDprocesses. Wet FGD processes are the most popular and the only processes that have the potentialto produce board-grade gypsum. These processes are well established and have been implementedat many Japanese and German utilities, and increasingly in North American ones as well. WetFGD processes use lime or limestone and may or may not produce gypsum co-product. Thecalcium sorbent reacts with SO2 to produce calcium sulfite hemihydrate, which can be oxidized tocalcium sulfate dihydrate (gypsum). The production of FGD gypsum has four stages:

Stage 1 — Desulfurization: The dedusted flue gas is sprayed into a washing towerwith a limestone suspension in a counterflow operation. The primary purpose ofdesulfurization is accomplished by eliminating the SO2 from the flue gas. Thecalcium sulfite thus obtained occurs as a sludge in the quencher of the washingtower.

Stage 2 — Forced Oxidation: Conversion of the calcium sulfite sludge into gypsumis achieved through its oxidation in the quencher of the FGD reaction vessel usingatmospheric oxygen. First, the highly insoluble calcium sulfite reacts with furtherSO2 to produce calcium bisulfite, easily soluble in water, that subsequently reactsspontaneously with atmospheric oxygen blown into the reactor to produce calciumsulfate dihydrate, i.e. gypsum. This second stage is the operation that leads to theconversion of waste sulfite into a product: FGD gypsum. In the course of thisstage, the gypsum crystals increase markedly in size, up to an average of 50 µm.

Stage 3 — Gypsum Separation: Large crystals of a desirable size are separated bymeans of hydrocyclone and collected in a separate vessel.

Stage 4 — Washing and Dewatering: Finally, in the last stage, the gypsum crystalsuspension is filtered or centrifuged, and the gypsum cake is washed with cleanwater to remove water soluble substances, especially chlorides, sodium andmagnesium ions. Dewatering to less than 10% moisture is achieved by means ofvacuum filters or centrifuges. The FGD gypsum thus obtained is a productchemically identical with natural gypsum. FGD gypsum is a salable, commercialgrade gypsum suitable for gypsum board manufacturing or any other applicationscalling for gypsum.


Processing of by-product gypsum by gypsum board producers poses challenges of its own. Dueto its very fine particle size and residual moisture, handling of by-product gypsum can be difficult.Even if modern filtration presses and centrifuges are used for dewatering, gypsum’s moisturecontent is in the 8 to 10% range when delivered to the gypsum board plants. Typically, by-productgypsum has to be dried prior to its calcination using a flash dryer or a fluidized bed dryer, requiringa major modification/up-grade of the existing natural gypsum handling operation. Drying of by-product gypsum with 10% moisture content requires about 0.55 GJ of thermal energy and 0.04 GJof electrical energy per tonne.14

Calcination

Calcination is perhaps the most important step of the gypsum processing and gypsum boardmanufacturing process. During the calcination, gypsum that in its dihydrate form contains 21% byweight of chemically bound water is heated and converted to stucco, calcium sulfate hemihydrate:

heat

CaSO4 • 2H2O ———> CaSO4 • 1/2 H2O + 1 1/2 H2O

Although different types of equipment are available for calcination of gypsum, calcination kettlesthat can be operated in either batch or continuous mode are the most commonly used equipment inNorth America. To produce gypsum board stucco, continuous calcination kettles are usually usedwith a throughput of 300 to 500 tonnes a day. Although several designs are available, the basicprinciple involves an externally heated cylindrical vessel with a height greater than its diameter,enclosed within a refractory shell and complete with stirrer, flues and internal baffles. Kettles canbe fired by coal, oil, or gas.

Gypsum (landplaster) is fed into the kettle from the top. Heat is introduced from a firebox belowand flows upward around the vessel. In submerged combustion kettles, a modern type of acontinuous kettle, a tube is installed so that combustion gases are discharged into the calciningmass. The kettle contents boil violently, as chemically bound water is released as steam at around120°C. Heavier stucco tends to settle at the lower section of the kettle from where it is continuouslydischarged through a plunging tube into a hot pit where cooling occurs. In practice due to theinability to heat all the particles of gypsum uniformly, the dumped stucco will often contain smallamounts of uncalcined gypsum as well as of completely dehydrated anhydrite. The moderncontinuous calcination kettles require about 0.9 GJ to 1.0 GJ of energy per tonne of finishedstucco.15 In older, less energy-efficient kettles, the energy consumption can be as high as 1.3GJ/tonne. Corresponding electrical energy requirements are given as between 0.01 GJ/tonne and0.03 GJ/tonne. Calcination consumes ~27% of the total energy required to produce gypsumboard13, and represents the second most energy-intensive step of the gypsum board manufacturingprocess.

Other types of calciners can be used, but lag in popularity behind the continuous calcination kettles.At one time, counter-current direct heating rotary kilns, similar to those used in Portland cementmanufacturing, were used by the gypsum industry. Due to the improved design and energy


efficiency of the calcination kettles, most of the rotary kilns in the gypsum industry were replaced.Now only Atlantic Gypsum in Corner Brook is using such a kiln. Domtar Gypsum is using Impmills (flash calciners with simultaneous impact hammermill grinding) in some of its operations, andLouisiana-Pacific’s gypsum fiberboard operation in Port Hawkesbury employs a Claudius Petersflash calciner that incorporates a ring ball grinder in its design. The energy efficiency of rotarykilns is similar to large continuous kettles, while that of flash calciners is reported to be slightlybetter.

Raymond mill, stucco bins

After stucco has cooled it is elevated to bins from where, in some plants, it is fed to a Raymond Millfor further grinding to get the fineness needed. In the Raymond Mill stucco is ground by rollsrunning centrifugally against the stationary outer ring.

2.2.3 Gypsum Board Plant

The layout of a gypsum board plant is usually U-shaped with the board line from the paper rollstands to the board cut-off knife forming one side of the U, the transfer station its bottom, and theboard dryer returning parallel to the board line its other side.11

Mixing

Stucco for gypsum board production is blown from the supply bins (or mill) to the board plant.The amount of stucco is metered and fed to the stucco feed system. Dry board additives andadmixtures such as starch, accelerator, retarder, and other ingredients depending on the type ofboard being made, are conveyed and blended with the stucco in a mixing screw conveyor. Theblended dry materials, water with premixed liquid additives such as water reducers, andpregenerated foam are fed directly into the pin mixer, and the resulting slurry is deposited in anumber of streams on the paper as it starts to form the board. To achieve the right fluidity of theslurry, a volume of water in excess of the amount needed for complete hydration has to be used.(This excess “water of convenience” will later be driven off during the drying process.) Two smalledge mixers are often used to prepare and deposit higher density slurry for the board edges, toimprove their strength and handling properties.

Paper

Gypsum board is frequently described as a sandwich, with gypsum in its core and paper as itsfacings. Making the paper for gypsum board is as complex a process as making the gypsum boarditself.9 The raw materials used are waste paper from newspaper, magazines, and old corrugatedcardboard. Waste paper is fed by conveyor into a pulper, a large “blender” that disintegrates anddissolves the old paper into a pulp, a slurry of paper fibers. The paper slurry is then cleaned ofvarious contaminants such as bailing wires, staples, glue and ink, before it is fed into the paper-making machine. Two types of paper making equipment, i.e. rotating cylinders or Fourdrinier flatwire machines, can be used to produce gypsum paper.


A cylinder machine rotates a large drum through a vat of pulp slurry. A wide felt belt passes overthe top of the turning drum of a cylinder. The cylinder pulls the pulp up and presses it against thebottom of the felt, where it sticks to form a single ply of paper. It takes nine cylinder-made pliespressed together to make a single continuous sheet of gypsum board paper.9 The characteristics ofthe pulp entering the vats determine whether the system produces cream stock, called “ivory”, usedfor the face of the gypsum board or gray stock, which makes the back side. The Fourdriniermethod uses two machines instead of nine to make a two-ply paper with the same performancecharacteristics as nine-ply, cylinder made paper. The pulp slurry is systematically fed onto acontinuously running wire screen (the Fourdrinier). As the screen moves forward, water drainsfrom the pulp to create the paper. One Fourdrinier machine makes the surface (top) ply, which maybe cream or gray stock depending on the pulp mixture. The second machine produces the gray(bottom) ply.

From this point, both systems operate in the same way. In the press section, the paper plies arepressed together to squeeze out the excess water. Next, they enter a series of high-temperaturedryers where any remaining water is removed. The “bone dry” paper enters what is called a“calender stack”, where different chemicals or treatments are applied to the top and bottomsurfaces to create the specific finishes required. For example, a dye and sizing agent will be addedto the top surface to produce the moisture-resistant characteristics for the moisture resistant(“green”) board. The face and back paper each weigh about 45 to 55 lb/MSF. On the basis ofone source16 that estimates the energy content of gypsum board paper prepared from recycledstock at about 25.4 GJ/tonne, we can extrapolate the related energy input into the finished gypsumboard at about 12.4 MJ/m2 of board.

Gypsum board line

The paper is placed on racks beside the pin mixer, where stucco slurry has been mixed with water.The racks run above and below the exit of the pin mixer, so that the stucco slurry can besandwiched between the paper. The stucco slurry is then spread onto the ivory-coloured face paperon a moving belt and covered, or sandwiched, with the top paper, or “gray back”, to be formed intogypsum board at the master roll. As the board passes along the belt line the edges are formed,shaped and sealed. The proper identification is printed on the “gray back”. The long continuoussheet of gypsum board now travels about 200 to 275 meters on moving belts and roller conveyorswhile setting (hydrating). The long board line is needed to allow the slurry time (about fourminutes) to harden before it is cut. By the time the end of the conveyor is approached, the stuccoslurry has set; hydrated back to gypsum.

Knife, transfer station

An automatic device trips a knife that cuts each board to the correct length. The individual boardsare now transferred, inverted, turned over, stacked six or even eight layers high and sent slowly backto the drying kiln.


Gypsum board drying kiln

In the drying kiln, the excess amount of water introduced into the slurry mix in the pin mixer inorder to have the slurry of the correct working characteristics, has to be driven off. Oil, gas or evenelectricity can be used as the source of heat in kilns. Drying of the gypsum board in the kilnconsumes more energy than all the other steps of the gypsum board manufacturing processcombined, representing ~67% of the total.13 The temperature and humidity in the kiln are closelycontrolled in three or four separate sections, first a lot of heat, then gradually less. After some 60minutes of drying the board emerges at the “take-off” end of the machine where it is inspected,taped in two-panel bundles, stacked and taken to the warehouse, ready for shipment.

2.2.4 Types of Gypsum Board Produced

The industry has developed and is producing a range of different gypsum boards for differentapplications. National Standard CAN/CSA-A82.27-M91 covers gypsum board, defines its varioustypes and specifies their composition and special properties. The types of gypsum board coveredinclude:

• gypsum board (regular gypsum board)• type X gypsum board (fire-resistant gypsum board)• vinyl-faced gypsum board• foil-backed gypsum board• gypsum backing board• water-resistant gypsum board• gypsum coreboard• gypsum sheathing• gypsum base for veneer plaster• gypsum lath• exterior gypsum soffit board

While some of the above boards, such as regular or type X, are produced in large volume, some ofthe other materials are specialties only. Furthermore, many of the above boards are made indifferent thicknesses: 1/2" and 5/8" gypsum board are among the more popular ones. StatisticsCanada does not provide a detailed breakdown for the volume of different boards produced,distinguishing only between plain gypsum board, gypsum board covered with vinyl or othersubstances, and sheathing.4 U.S. statistics are published by USDI Bureau of Mines2, and thebreakdown of various boards is more detailed. It states that of the prefabricated products, based onsurface area,

• 63% was regular gypsum board,• 24% was fire-resistant type X gypsum board,• 5% was 5/16" mobile home board,• 3% was water- and/or moisture-resistant board, and the remaining• 5% covered lath, veneer base, sheathing, predecorated, and other types of board.


Of the gypsum regular board,

• 82% was 1/2", and• 10% was 5/8".

A detailed breakdown of gypsum board consumed in the U.S.A. is given in Table 2.2, and in theabsence of similar Canadian data we will assume a similar split for Canada as well.

TABLE 2.2: TYPES OF GYPSUM BOARDS SOLD OR USED IN THE U.S.A., 1994

Product Thousandsquare feet

Thousandtonnes

Value[US $]

%(based on

area)

Lath: 3/8" 6 , 8 8 6 4 1,410 0 . 0 2 9 7 1/2" 1 3 7 > 0.5 24 0 . 0 0 0 6 other 5 , 8 6 7 5 407 0 . 0 2 5 3

Total lath 1 2 , 8 9 0 10 1,841 0 . 0 5 5 6

Veneer base 419 ,149 374 36,667 1 . 8 0 7 0

Sheathing 286 ,166 242 33,544 1 . 2 3 3 7

Regular gypsum board: 3/8" 918 ,125 711 69,102 3 . 9 5 8 2 1/2" 11 ,885 ,323 9,357 1,487,447 51 .2395 5/8" 1 ,466 ,834 1,225 57,282 6 . 3 2 3 8 1" 172 ,079 155 31,905 0 . 7 4 1 9 other (1/4", 7/16", 3/4") 128 ,872 101 16,470 0 . 5 5 5 6

Total regular board 14 ,571 ,233 11,548 1,662,206 62 .8189

Type X gypsum board 5 ,526 ,219 5,157 460,985 23 .8244

Predecorated board 8 7 , 0 6 6 78 27,872 0 . 3 7 5 4

5/16" mobile home board 1 ,226 ,687 843 117,345 5 . 2 8 8 4

Water-resistant board 658 ,432 558 84,529 2 . 8 3 8 6

Other 407 ,790 382 27,168 1 . 7 5 8 0

Grand total 23 ,195 ,632 19,192 2,452,158 100 .0000

Source: adapted from Ref. (2)


2.3 GYPSUM FIBERBOARD

2.3.1 Gypsum Fiberboard Manufacturing

The basic raw materials for the production of gypsum fiberboard in Louisiana-Pacific’s plant inNova Scotia are local natural gypsum, waste newsprint/magazine stock from the U.S./Canadian eastcoast, and perlite from Greece or New Mexico.18 Various additives and admixtures such as lime,starch, accelerators, etc., are used as well. The board has a 3-layer composition: the surface layerscontain paper fibers and stucco, the core layer also contains expanded perlite, which helps to controlthe board density by reducing its overall weight by 20 to 25%.

Raw materials preparation

The basic material flow is shown in Fig. 2.2. The waste paper bales are transported to the plant siteby barge. (The barge also takes the finished product back to the consumers in the more populatedareas on the east coast.) The waste paper is broken down first in a shredder to 2" x 2" clippings.The hammermill reduces the particle size further to about 1" x 1" pieces, which are subsequentlymilled down to fibers and wetted. Perlite arrives by truck and is expanded in four parallel lines toabout eight times its original volume. In a primary blender, perlite is mixed with water, and in asecondary blender wet fibers are added to wet perlite. Natural gypsum comes to the plant from thelocal Nova Scotia mine by rail.18 Gypsum rock extraction, preparation and calcination is done in asimilar manner as for conventional gypsum board, and as discussed in Sections 2.2.1 and 2.2.2above.

Board forming and pressing

It is in the raw materials streams mixing, board forming and pressing, that GFB processing differsfrom gypsum board manufacturing. The process is considered to be “semi-dry”, the amount ofwater added to the raw materials (fibers and perlite) and on the line just before it enters the press iscarefully controlled and is close to the theoretical amount needed for stucco hydration. The threelayers and related three raw material blends are kept separate in handling and deposition on the line,and can be identified in the finished product.

The forming station consists of three conveyor belts, one for each surface layer and one for the corelayer. In each layer a weight-controlled layer of prewetted fibers or prewetted fibers and perlite isformed and a weight controlled layer of stucco is put on the top. Unmixed layers of wet and drymaterials are conveyed to the mixing heads in front of the press, and spread onto the press belt.The board is produced in a continuous roller type COE Manufacturing (Washington Iron Works)press. The press is about 30 meters long, and the residence time of the board in the press is about 3minutes. As the stucco setting characteristics are accelerated by means of additives, the initial boardsetting is finished before the board leaves the press.



by-productgypsum

(FGD or TiO2)

or

crusher screengypsum

bin

ClaudiusPetersflash

calciner

screenRaymond mill

stuccobin

additives

cross cutsaw

stacking,bundling

GFB to warehouse & shippingboard dryer

papershredding

fibermills

perlite

perliteexpansion

blending

wastepaper

spreading surface

layers fibres

spreadingcentre layer

fibres & perlite

mixing mixing

continuous pressforming belt

moisture

Fig. 2.2 Flow diagram of a gypsum fiberboard (GFB) plant with a Claudius Peters flashcalciner (adapted from Refs. 18, 34).


Board line, kiln dryer

After the press, the continuous ribbon of the “green board” is cut to 22- or 24-foot-long piecesusing a high pressure water jet, and after about 15 minutes spent moving on the conveyor andcompleting the hydration in a manner similar to that of conventional gypsum board, GFB enters thefirst heating zone of an 8-deck Dornier dryer. The dryer has a screen belt as a carrier and jetnozzles to distribute the hot air evenly onto the boards. It has 17 heating zones, each individuallycontrolled. The source of heating energy is propane gas. The residence time of the board in thekiln dryer is about 25 minutes, and the final board moisture content is about 0.8%. A finishing areafor final trim and cutting, application of seal coat, stackers etc. follows the dryer.18

2.3.2 Types of Gypsum Fiberboard Produced

Louisiana-Pacific is producing three types of gypsum fiberboard:

• 1/4" and 3/8" FiberBond® GFB floor underlayment,• 1/2" and 5/8" FiberBond® GFB exterior wall sheathing, and• 1/2" and 5/8" FiberBond® GFB board.

As noted in Section 2.1.2, we estimate that all L-P’s FiberBond® GFB products combined have a2.8% share of the total Canadian gypsum board production.

2.4 GYPSUM BUILDING PLASTERS

2.4.1 Gypsum Building Plasters Manufacturing

As noted in Section 2.1.3, gypsum board largely replaced plaster as the premier wall-claddingmaterial. Their market share in Canada is limited, and their manufacturing process is discussedhere only briefly.

Extraction, crushing, milling, calcination, stucco milling

The gypsum plasters manufacturing process, with the exception of final milling, formulating andbagging, is the same as that of gypsum board. Steps 1 through 5 of the gypsum board production,i.e. extraction and preparation of raw materials, their crushing and milling, and the calcinationprocess with subsequent grinding in a Raymond mill, as described in Section 2.2.1 and 2.2.2 arethe same. (However, some gypsum facilities use separate production lines and smaller batch kettlecalciners to give them more flexibility in producing plaster stucco. Another reason for a separateline is that the inclusion of paper fibers from the recycled gypsum board construction waste inbuilding plasters is undesirable.) Fig. 2.3 shows a flow diagram of the gypsum plastermanufacturing process.



by-productgypsum

(FGD or TiO2)

or

crusher screen

hammer mill

gypsumbin

batchkettle

calciner

screentube mill

additives

building and industrial plasters to warehouse & shipping

stuccobin

stuccobin

stuccobin

weighting / mixing belt

mixing &packingstations

Fig. 2.3 Flow diagram of a gypsum building and industrial plasters manufacturing plant witha kettle calciner (adapted from Ref. 7).


Plaster Manufacturing - Grinding / Tube mill

Raymond mill stucco is passed through a tube mill. This is a long tube filled with iron balls ofvarious sizes which grind the stucco to the required fineness. Plasters require stucco of highersurface area than gypsum board stucco.

Additives / Plaster mixer / Packer

Plaster additives such as lime, talc, clays, and various admixtures regulating plaster set, are mixedwith the tube mill stucco in the plaster mixer to produce plaster of the desired handling, applicationand performance properties. The building / veneer plasters (or industrial plasters) are then baggedin the packer and taken to the warehouse for shipment.3

2.4.2 Types of Plasters Produced

The market for building/veneer plasters is small. Some gypsum manufacturers produce plasters inCanada, others bring them from the U.S. There is little information in the public domain regardingthe size and regional distribution of veneer plasters in Canada. In the U.S.A. 553,000 tonnes ofplasters were produced in 1994 vs. 19,200,000 tonnes of gypsum board.2 The above tonnage forplasters, however, is the total for building and industrial plasters, which normally split the totalproduction in about a 60 to 40 ratio. Our estimate, based on some Gypsum Associationbreakdowns between different types of materials, is that in the U.S. the following volumes ofdifferent calcined gypsum products were produced in 1994 (Table 2.3).

TABLE 2.3: CALCINED GYPSUM PRODUCTS SOLD OR USED IN THE U.S.A. IN 1994

Product Volume [tonnes] %

Regular Plasters 155,400 0.79 Veneer Plasters 148,900 0.75 Gauging Plaster & Keene's Cement 24,700 0.13

Sub-total Building Plasters 329,000 1.67

Sub total Industrial Plasters 224,000 1.13

Total Building and Industrial Plasters 553,000 2.80

Prefabricated Products (Gypsum board) 19,192,000 97.20

TOTAL CALCINED GYPSUM PRODUCTS 19,745,000 100.00


In the absence of similar Canadian data we will assume that plaster products have a similar share ofthe market in Canada, athough there are some indications that they are used here even less than inthe U.S. However, as the total of all building plasters represents only 1.67% of the total calcinedgypsum products, we will omit them from development of detailed unit factor estimates, andconcentrate instead on a variety of gypsum boards dominating the gypsum products markets.


2.5 JOINT FINISHING PRODUCTS MANUFACTURING

To apply gypsum board and to finish joints, drywall nails or screws are needed, as well as drywalltape and joint compound. Gypsum board manufacturers20 provide typical usage for theseassociated finishing products as follows:

• ready mixed joint compound: 67.4 kg/100 m2

• setting joint compound: 35.2 kg/100 m2

• paper tape: 98 m/100 m2.

Similarly, the approximate usage for various fasteners is as follows:

• drywall nails 1 1/4": 2.20 kg/100 m2

• 1 5/8": 2.81 kg/100 m2

• drywall screws 1 1/4": 2.07 kg/100 m2

• 1 5/8": 2.73 kg/100 m2.

2.5.1 Ready Mix Joint Compound

Ready mix joint compounds represent over 90% of the total joint finishing materials used inCanada. Their formulas are proprietary, nevertheless they share the same major raw materialcomponents, and their development is as much an art as it is a science. An experienced formulatoris critical to their success. Generic formulations used in the development of the unit factors in thisstudy are shown later. The two main constituents of ready mix are:

• water, acting as a vehicle, and• calcium carbonate (CaCO3), finely ground limestone, functioning as a filler.

These two raw materials represent about 80 to 90% of the total composition. In some formulationsa portion of limestone is replaced by gypsum. Other components whose share is above 2% (byweight) of the total can include:

• talc,• mica,• specialty clays, such as attapulgite or kaolin, and• resin (latex), usually polyvinyl acetate, functioning as a binder.

Lightweight formulas can contain perlite. The joint compound formulas are completed withdifferent admixtures and additives, such as cellulosic thickeners, starches, surfactants, dispersants,flocculants, and preservatives (antibacterial and antifungal agents); all of these being used in minutequantities only. Typically, ready mix compounds contain about 65% solids. Virtually all of these,as indicated, are industrial minerals that are quarried or mined, crushed and ground to theappropriate fineness. Joint compound manufacturers generally purchase rather than mine the rawmaterials. The basic manufacturing process is depicted in Fig. 2.4 and summarized below.


warehousing & shipping

dry rawmaterials

in bulk

bagged dry rawmaterials &additives

resin

water

ribbon mixer

dry powdermixer

pump discharge

weigh scale & inspection

station

pulverizer

packer packer

valve bags

weigh scale& inspection

station

pails or box containers

palletizer

Fig. 2.4 Flow diagram of a joint compound producing plant (adapted from Ref.7).


Industrial minerals extraction & preparation

The main component, calcium carbonate, is abundantly available. Limestone is mined by open-pitmethods, requiring no special equipment. Overburden is removed using bulldozers, draglines, orhydraulic shovels. The rock is drilled and blasted. The broken stone is loaded into dump trucksand hauled to the primary crushers, or it is loaded onto a conveyor and carried directly to a portableor permanent crusher. For most uses of limestone, it must travel through a secondary crusher andbe sized. Where fine particle size is required, as in joint compounds, it has to be ground.16,21

Other industrial minerals used, such as talc, mica and clays are extracted and prepared in a similarmanner. The mining and production of gypsum have been discussed under gypsum board (Section2.2.1).

Latex binder

The only raw material accounting for more than 2% of the mass of the ready mix joint compoundcomposition other than industrial minerals is a latex binder, usually polyvinyl acetate (PVA).Polyvinyl acetate is prepared by introducing a benzene solution of vinyl acetate with a catalyst into ajacketed vessel. The mixture boils at 72°C, and the vapours are returned to the kettle. After aboutfive hours at a gentle boil, the reaction mixture is run to a still and the solvent and unchanged vinylacetate are removed by steam distillation. The molten resin is run into drums, where it solidifies, oris extruded into rods and sliced into flakes.22 It is usually supplied to the joint compoundmanufacturers in the form of a 55 to 60% solids emulsion.

The precursor of polyvinyl acetate, vinyl acetate is manufactured by reacting ethylene, derivedusually from natural gas, with acetic acid in the vapour phase over a palladium catalyst. Thereaction takes place in a fixed-bed tubular reactor and is highly exothermic. When the reaction isconducted under the correct conditions, the only significant by-product is CO2. Enough heat isrecovered as steam to perform the recovery distillation. The reaction occurs at 175 to 200°C underpressure of 475 to 1,000 kPa. 22

Ready mix joint compound manufacturing process

Limestone, and sometimes the other larger volume components, are stored in bulk facilities.Limestone is weighed as are the other dry raw materials, and often pre-mixed in a dry blender. Drypremix is fed via weigh hopper and screw conveyor into wet blenders, either a paddle- or acontinuous-ribbon-type. Liquid ingredients (water, PVA emulsion) are distributed through a pipingsystem. Following the blending operation, finished ready mix compound is transferred intoholding tanks, either by gravity or using Moyno pumps, usually de-aerated under vacuum, andpackaged either in pails or in lined boxes.

2.5.2 Dry (Setting) Joint Compound

Gypsum stucco accounts for about 70 to 75% of the total formulation in setting compounds.Calcium carbonate and mica are other major ingredients, while clays, starches, gels, hydrated lime,accelerators and retarders are typical additives used in smaller quantities. Perlite can be used in


lightweight formulas, as well. The main formulation components, gypsum stucco, calciumcarbonate and mica are extracted, prepared, and in the case of gypsum, calcined to stucco, asdescribed in detail in previous sections. All the ingredients are weighed and mixed in dry paddle orV-shell blenders. Dry setting compounds are shipped in bags, and they are offered in a range ofdifferent set times, 45-minute and 90-minute ones being the most popular. Recently somelightweight setting compounds have become available as well.

2.5.3 Products Statistics

Canadian production volumes for joint filler compounds in 1994 are shown in Table. 2.4.4

TABLE 2.4: PRODUCTION OF JOINT FILLER COMPOUNDS, 1994

SCG Code 1994 Production[tonnes]

Ready mix 2520.20.90 131,844Dry powder 2520.10.13 11,877


2.5.4 Joint Paper Tape

Most joint tape is manufactured from paper similar to the “ivory” bleached paper used as facing ofthe board. Papermaking raw materials and production were discussed in Section 2.2.3 under“paper” for gypsum board. Paper is cut into proper widths (typically 2 1/16"), sanded and buffed,and perforated. All paper joint tape is creased in the middle to accommodate taping of insidecorners. Joint tape is sold in rolls, either boxed in bulk, unpackaged, or wrapped in plastic.

Use of paper joint tape is the most widespread, although a small quantity of glass mesh tapepioneered by a Canadian company, Bayex Division of Bay Mills Ltd., is used mainly by the DIYmarket. Statistics Canada does not provide their relative market share, but it is apparently growing.

2.6 GYPSUM INDUSTRY, ENERGY AND ENVIRONMENT

Like any industry, gypsum board manufacturing uses energy resources and emits some pollutantsto the atmosphere. It also generates some liquid effluents and solid wastes. At the same time,gypsum board is perhaps one of the more environmentally friendly building products because of:

• the long established use of recycled newsprint and cardboard in the production ofits paper facings,

• essentially 100% recycling of in-plant and increased volume of construction wastegypsum board back into production, and


• the recent development of synthetic (by-product) gypsum replacing some of thenatural gypsum.

2.6.1 Energy Use and Efficiency

Energy used for drying/grinding of gypsum raw materials (~6% of total energy), gypsumcalcination (~27%) and gypsum board drying (~67%) constitutes a major cost in gypsum boardproduction (around 18% of the total direct manufacturing costs).13 As a result, the industry mademajor, conscientious strides to reduce their energy consumption, especially following the oil costincreases during the 1970’s. A shift from batch kettle calcination to continuous kettle calcination,and optimization of the firing process significantly improved efficiencies and energy consumption.Modern well-designed continuous kettles such as are used in most of the North American facilitiesrequire approximately 1 GJ/tonne of hemihydrate.15 Recent development of improved calcinationmethods, such as kettles with submerged combustion and conical kettles offer further improvementsin energy efficiencies. Energy input of 0.65 GJ/tonne was measured for 72% purity gypsumcalcined in a conical kettle.23-25 (Table 2.5)

TABLE 2.5 TYPICAL EFFICIENCIES AND ENERGY CONSUMPTION OF DIFFERENT CALCINATION KETTLES

Type of Kettle Energy Efficiency Energy Consumption [GJ/tonne]

@ 72% purity @ 90% purity

Batch 55 0.98 1.21Continuous 65 0.82 1.02Continuous with submergedcombustion

75 0.71 0.88

Conical 90 0.65 0.70 @ 81.5%

Source: adapted from Refs. (23-25)

Judicious selection of fuels as well as insulation, a sophisticated temperature control regime andheat recirculation/recovery on the gypsum board drying kilns implemented following the energycrisis also resulted in energy efficiency improvements.

Industry data indicate an average expenditure of 36.3 GJ/tonne of paper produced.28 This can varyfrom about 28.2 GJ/tonne if the paper is produced in an integrated mill, to 39.0 GJ/tonne if it isproduced in a pulp mill followed by a paper finishing mill. However, the gypsum industry has beenusing paper made from recycled newspaper and cardboard since the 1950’s; a long time before itbecame environmentally “popular”. It is estimated that paper products manufactured fromrecycled material require approximately 27 to 44% less energy than from virgin wood, dependinglargely upon whether the paper is bleached or unbleached.28 It is assumed that for the gypsumboard industry, which uses bleached kraft paper, the energy savings is probably in the 30% range16,bringing the energy content from 36.3 GJ/tonne down to about 25.4 GJ/tonne. As about 100 lb of


paper is used per MSF of board (0.5 kg/m2), a contribution of about 12.45 MJ/m2 of gypsumboard can be attributed to the paper.

2.6.2 Atmospheric Emissions

Mining of gypsum, as well as its crushing, grinding, and handling in the plant, including thecalcination step of the process, result in particulate emissions. Similarly extraction and processingof other industrial minerals, such as calcium carbonate, talc, mica and clay, used in the jointcompound manufacturing, will cause some particulate emissions.

Energy consumed in the extraction process, in the raw materials transportation, as well as gypsumboard manufacturing and subsequent shipping to the markets, will result in emissions of CO2, CO,SO2, NOx, CH4 and VOCs, as in any process where energy is used. However, gypsum calcinationproduces less NOx than production of such materials like cement or lime where high temperaturesresult in significant thermal NOx. In contrast, gypsum calcination requires relatively lowdehydration temperatures, in the 120° to 140°C range. Below 1000°C no significant thermal NOxis generated.26 As far as CO2 is concerned, during the gypsum calcination there is only fuel CO2generated. In gypsum processing, there is no dissociation of the calcium sulfate molecule as is thecase in the calcium carbonate calcination in the cement and lime manufacturing, and therefore nochemical (calcination) release of CO2.

The handling and blending of dry raw materials for gypsum board in plant operations, as well as thecutting of the finished board result in some particulate release. Bag houses and other emissioncontrols are employed to minimize particulate release.

In the production of a moisture (water) resistant gypsum board, asphalt or wax emulsions areusually used to treat the board (albeit in very small quantities). Their precursors are petroleumproducts and a variety of pollutants, including VOCs and hydrocarbons are released during thedrilling, extraction, and cracking of petroleum. However, the amount of such releases that would beattributable to gypsum board are negligible. Regular or type X gypsum board itself does notcontain any VOCs, however, there is some indication in the literature that gypsum board can absorbVOCs released from other building materials used during construction, and then release them at aslower rate back into the indoor air.16 There appears to be a lot of confusion on this subject, withno definitive conclusion at this time.

Like gypsum board manufacturing, joint compounds production contributes to the particulateemissions, as it uses mainly dry powder ingredients. Particulates are released in the extraction andprocessing of the raw materials (calcium carbonate, gypsum, talc, mica, clays, perlite), and in theirhandling and blending in the manufacturing stage. Ethylene, the precursor of PVA used as a binderin the ready mix joint compounds, will contribute to emissions of VOCs and benzene, a highlyregulated, known carcinogen. But again, only a very small amount of such releases would beultimately attributable to joint compounds on a per unit basis. The uncontrolled emission factor forVOCs is 8.35 kg/tonne of ethylene, and the uncontrolled emission factor for benzene is 1.11kg/tonne of ethylene. The controlled emission factor for benzene is 0.0845 kg/tonne of ethylene.16


2.6.3 Liquid Effluent

In comparison with most of the paper manufacturing, gypsum paper production using recycledpaper stock substantially reduces water usage and associated effluent discharges, which couldotherwise result in increased turbidity from suspended solids, increased alkalinity, reduced BOD,and increased deoxygenation. Most of the paper used in the production of gypsum board ispostindustrial newsprint. When such paper is deinked, residues end up in leftover sludge. Aboutone-fifth of the wastepaper material is drawn off as sludge, which contains not only ink residues,but also fillers, clay, fiber fragments, and other materials. The inks on the newsprint, however, aretypically non-toxic, and the sludge from many deinking mills is being used by farmers as clay-heavy soil conditioner.28

While there are closed water-loop process technologies available, and many end-of-pipe controlimprovements were implemented over the last few decades with respect to effluent releases from thepaper mills, some problems still remain. Nevertheless, the paper industry record in general isimproving. Canadian paper mills (all combined) reduced their total suspended solids (TSS)discharges from 2,106 tonnes/day in 1978 to 816 tonnes/day in 1985. Discharges of BOD fellfrom 3,337 to 1,961 tonnes/day during the same period of time, while production increased fromabout 51,000 tonnes/day to 74,000 tonnes/day.29

In the gypsum board manufacturing process, apart from quarry water and stormwater generated inthe extraction of gypsum rock, there is very little liquid effluent. (If by-product gypsum is used,such material may have to be washed by its producer to reduce the soluble salts [Na+, Mg++, Cl-]content for gypsum to be acceptable by the gypsum board plant.).

The paper manufacturing process, including that of gypsum facing paper, is a large generator ofliquid effluent containing suspended solids and organic pollutants. (On average, in the productionof pulp and paper, each tonne of paper requires about 100 m3 of process water, although the actualamount consumed depends on the production process.29

Ready mix joint compounds manufacturing operates in a closed loop system; consequently noliquid effluent is generated with the exception of a very low, non-measured effluent from theoccasional washing of the production equipment and area.

2.6.4 Solid Waste

Extraction of gypsum rock, in contrast to many other quarrying and mining operations, generatesvery little waste, as gypsum rock is usually used in its entirety in the manufacturing process, withoutany separation of the impurities, refining or smelting of the desired materials from the rock. In thefew operations where some beneficiation of the rock is required, the main contaminant is usuallylimestone, which is resold as aggregate for road building or similar applications.


A small amount, typically 5% to 10%, of waste gypsum board is generated in its production duringthe start-ups, due to the production of off-specs board, and due to the cutting and trimming of theboard. As already noted, all the in-plant generated solid waste is recycled back into production.Some of the off-specs board is cut and used for sleutters to support pallets of the finished board,thus eliminating the need to use 4" x 4" wood supports.

In joint compound production no other solid waste is generated than the raw materials packaging.Most often, however, the packaging paper bags are shipped back for recycling.

2.6.5 Recycling

The use of industrial by-products (FGD or TiO2 gypsum) and post-industrial waste (waste paper,gypsum board construction waste) as raw materials in the production of gypsum board was alreadymentioned. In our calculations, energy associated with transport of gypsum board constructionwaste back to the production facility is accounted for. This recycling and reuse of by-products andwastes is one of the major strengths of the gypsum industry. As noted in Section 2.1.1, in 1995Westroc’s Mississauga plant became the first Canadian gypsum board plant operating entirely onFGD by-product/waste gypsum, with a number of other operations supplementing their gypsumrock supply with by-product gypsum, or construction waste gypsum.

In at least two Canadian metropolitan areas, Vancouver and Toronto, construction gypsum boardwaste is banned from landfill sites. It is being collected by recyclers, and supplied back to thegypsum board manufacturing plants. An alternate use for construction waste, according to theGypsum Association, includes agricultural applications and animal bedding material.16 Beneficialre-use of either by-product or waste construction gypsum reduces pressure on scarce landfill sites.

The availability of free, or very inexpensive by-product gypsum, is changing the gypsum industry.In years to come, it is expected that more and more FGD gypsum will be used where it makeseconomic and geographic sense.3 In 1992 in the U.S.A. over 25.5 GWe of coal-fired powergenerating plants were already operating, under construction, or planned to be equipped with wetlime/limestone scrubbers generating FGD gypsum. It is expected that by the end of the decadesome 7.3-million tonnes of FGD gypsum could be available.31,32 To put that number inperspective, it represents about one-third of the total U.S. annual consumption and almost one-halfof its gypsum mining output. Other sources forecast an eventual U.S. production of syntheticgypsum as high as 32-million tonnes annually.33

In Canada 1.5 GWe power generating capacity already is or soon will be similarly equipped.30

Canadian FGD gypsum production capability, estimated on the basis of Canadian vs. U.S. wetlime/limestone scrubbing capacity, appears to be in the 500,000 tonnes/year area. This figure seemsto correspond well with the FGD gypsum generating forecasts expected from the Ontario Hydro’sLambton and New Brunswick’s Belledune power stations.


REFERENCES

1. O. Vagt, “Gypsum and Anhydrite”, Canadian Minerals Yearbook, 1994, Natural ResourcesCanada, Ottawa, 1995.

2. “Gypsum”, Annual Review 1994, Mineral Industry Surveys, U.S. Department of Interior -Bureau of Mines, Washington, DC 20241, August 1995.

3. G.J. Venta, R.T. Hemmings, “FGD Gypsum Utilization: A Strategic Approach to Reuse”,Proceedings , Paper 95-WA80.03, Air & Waste Management Association 88th AnnualMeeting & Exhibition, San Antonio, TX, June 18-23, 1995.

4. “Gypsum Products”, December 1994, Statistics Canada Catalogue 44-003/ISSN 0380-7223,Vol. 45, No.12

5. G.J. Venta, R.T. Hemmings, E.E. Berry, “A North American Perspective on Recycling andReuse of Waste and Industrial By-Products in Building Materials”, Proceedings of ReC’93International Recycling Congress, Geneva, Switzerland, January 1993.

6. Toronto Star, November 10, 1995.7. “Gypsum / Magic Mineral”, CGC Inc.8. “The Story of Gypsum / How Gyproc is made”, Domtar Gypsum.9. “How Gypsum is made”, Construction Dimensions, February 1991, pp.34-37.10. “The Gypsum Industry and Flue Gas Desulfurization (FGD) Gypsum Utilization: A Utility

Guide”, EPRI Report TR-103652, prepared by NYSEG and ORTECH, February 1994.11. “Board Machinery”, The COE Manufacturing Company, Bulletin 7000.12. “Board Production - Plant Design, Operational Layout, Manufacturing”, Combustion

Engineering, Inc. Bulletin No. 123.13. L.M. Luckevich, “Microwave Drying of Gypsum Board”, paper presented at the 81st Annual

Meeting and Convention of the Canadian Ceramic Society, Montreal, PQ, February 1983.14. F. Wirsching, “Calcium Sulfate”, Ullmann’s Encyclopedia of Industrial Chemistry, 5th

edition, 1985, Vol. A4, pp. 555-584.15. R.J. Wenk, P.L. Henkels, “Calcium Compounds (Calcium Sulfate)”, Kirk Othmer Scientific

Encyclopedia, 1978 edition, Volume 4, pp.437-448.16. “Gypsum Board Systems: Technical Report”, Topic I-9250, AIA Environmental Resource

Guide, July 1993.17. G.J. Venta, “Gypsum Fiberboard: A High Performance Specialty Board”, Proceedings of the

3rd International Conference on Inorganic-Bonded Wood and Fiber Composite Materials,Spokane, WA, September 28-30, 1992, pp.66-77.

18. G. Natus, “Gypsum Fiberboard Production in Nova Scotia”, Proceedings of the 2ndInternational Conference on Inorganic-Bonded Wood and Fiber Composite Materials,Moscow, ID, October 15-17, 1990, pp.85-87.

19. “FiberBond® Fiber-Reinforced Gypsum Panels”, Louisiana-Pacific, October 1993.20. “Gypsum Construction Handbook”, 3rd edition, USG, 1987, p. 61.21. “Building Materials in the Context of Sustainable Development - Raw Material Balances,

Energy Profiles and Environmental Unit Factor Estimates for Cement and Structural ConcreteProducts”, Report prepared by CANMET and Radian Canada Inc. for Forintek Canada Corp.,October 1993.


22. “Gypsum Board Systems: Technical Report”, Topic I-9250, AIA Environmental ResourceGuide, July 1993, p.24, adapted from G.T. Austin, “Shreve’s Chemical Process Industries”,5th edition, 1984.

23. A.G.T. Ward, “Methods of Reducing Energy Requirements in Kettle Calcination”, Ciments,Betons, Platres, Chaux, No.728 - 1/81, pp. 51-56.

24. R. Lewis, “Improved Methods of Calcination”, Ciments, Betons, Platres, Chaux, No.753 -2/85, pp. 99-105.

25. R. Lewis, “Improved Calcining Process for Gypsum”, Zement-Kalk-Gips, 38, No 5/1985, pp.250-255.

26. J. Zelkowski, “Kohleverbrennung”, VGB Technische Vereinigung derGrosskraftwerksbetreiber e.V., Band 8 der Fachbuchreihe “Kraftwerkstechnik”, VGB-B0081986.

27. American Gas Association, “Industrial Sector Energy Analysis: The Paper Industry”,February 1988.

28. “The Tellus Institute Packaging Study Project: Summary”, Tellus Institute, November 1991.29. ‘The State of Canada’s Environment”, Chapter 14 - Industries, Pulp and Paper Production,

Government of Canada, Ottawa, 1991, pp. 14-18/19.30. H.N. Soud, M. Takeshita, “FGD Handbook”, Chapter 4 - FGD Installations on Coal-Fired

Plants, IEACR/65 Report, IEA Coal Research, London, January 1994.31. G.J. Venta, R.T. Hemmings, “FGD Gypsum Utilization: Bridging the “Two Solitudes”,

Proceedings of 11th International Symposium on Use and Management of Coal CombustionBy-Products (CCBs), American Coal Ash Association, Orlando, FL, January 15-19, 1995.

32. W. Ellison, R.A. Kuntze, “Expanding of Markets for Gypsum Byproducts”, Proceedings ofSociety for Mining, Metallurgy and Exploration, Inc., 1993 Annual Meeting, Reno, NE.

33. J.A. Walker, “Gypsum - The Miracle Mineral: Brief History and Prospects”, Proceedings ofthe 4th International Conference on Inorganic-Bonded Wood and Fiber Composite Materials,Spokane, WA, September 26-28, 1994, pp.39-40.

34. “Schenck Gypsum Fiberboard Plant – Future-Oriented Technologies for Innovative Panels”,Carl Schenck AG bulletin V 0224.


3.0 RAW MATERIAL REQUIREMENTS AND TRANSPORTATION

This section provides a brief overview of raw material requirements for gypsum board andassociated products production in Canada on a regional basis. The section also provides anoverview of transportation distances and typical modes used to move raw materials to the gypsumplants, again on a regional basis. Transportation data underlying the overview was used to developcorresponding energy estimates presented in Section 4.0.

Data on actual raw material requirements, transportation distances and modes was provided toVG&A by the three major gypsum board producers for all their plants listed in Table 2.1(preceding section). However, we are treating the individual plant data as confidential and all datapresented in this report is therefore shown as averages, typically weighted averages on a regionalbasis. The weights used to develop these and other estimates presented in later sections are theactual utilized capacities for 1995 as provided directly by the producers.

For the Newfoundland plant which did not provide detailed raw material and transportation data, weestimated transportation distances and modes based on the industry and market generalinformation. For the one GFB plant in Nova Scotia that did not provide this data directly, we madeassumptions based on their published information18.

3.1 RAW MATERIAL REQUIREMENTS - GYPSUM BOARD

Gypsum board formulations are essentially identical from one region of the country to another, andfrom one part of the North American continent to another. The differences between raw materialsfrom one producer to another are also rather insignificant. Generally, board formulations consist of48% to 55% gypsum stucco, around 2% to 5% paper, and 42% to 46% water, on a mass basis.

As discussed in Section 2, gypsum stucco, the primary raw material in the board production, isproduced through calcination of gypsum. One tonne of gypsum rock (or by-product) yields about830 kg of stucco. In other words, 1.2048 tonnes of gypsum is needed for 1 tonne of stucco. Paperused as facings of gypsum board is made from recycled waste paper; it is assumed that1.1 tonnes of raw materials (waste paper) is needed to produce 1 tonne of gypsum paper. Thesefactors are included in relevant calculations and estimates.

While a number of admixtures and additives, such as accelerators, retarders, plasticizers, glassfibers, potash, dextrose, starch, emulsions, paper pulp, clay and perlite are used, depending on thetype of gypsum board produced (standard, fire resistant (type X), or moisture resistant), theiraggregate amount is only between 0.9% and 2.5%. None of the individual additives reach the 2%limit recommended as a cut-off level in the ATHENATM project Research Guidelines, and thereforetheir specific energy and emissions estimates were not developed.


In contrast to conventional gypsum board, gypsum fiberboard, due to the nature of its process(semi-dry technology), uses substantially less water. To lower the GFB product weight and toapproach that of gypsum board, expanded perlite is used in the core layer of the board.

Typical gypsum board formulations for ten (10) different gypsum board products are shown inTable 3.1 in kg of raw materials per m2 of finished board. Table 3.2 provides the same breakdownin percentages. These breakdowns by type of product and board thickness are used throughout thedevelopment of the unit factor estimates in all subsequent sections.

TABLE 3.1 GYPSUM BOARD GENERIC FORMULATIONS / AVERAGE RAW MATERIALS USE (KG/M2 OF FINISHED BOARD)

1/2" regular 5/8" regular 1/2" type X 5/8" type X 1/2" MR

Stucco 6.3610 8.3057 6.3329 8.4239 6.9755Paper 0.4715 0.4773 0.4507 0.4649 0.4847Water 5.4273 6.8308 5.3773 6.8967 6.6290Other 0.1108 0.1493 0.2761 0.1523 0.3674Perl i te 0.0000 0.0000 0.0000 0.0000 0.0000

TOTAL (wet weight) 12.3706 15.7632 12.4370 15.9378 14.4566

(dry weight) 8.0632 10.2867 8.1854 10.5066 9.0406

5/8" MR 5/16" mobilehome

1" shaftliner 1/2" GFB 5/8" GFB


TOTAL (wet weight) 18.3360 9.2848 28.3500 11.3859 14.1276

(dry weight) 11.4840 5.8642 19.0585 11.1908 13.9762


TABLE 3.2 GYPSUM BOARD GENERIC FORMULATIONS / AVERAGE RAW MATERIALS USE (% BREAKDOWN)

1/2" regular 5/8" regular 1/2" type X 5/8" type X 1/2" MR


TOTAL (wet weight) 100.00 100.00 100.00 100.00 100.00

5/8" MR 5/16" mobilehome

1" shaftliner 1/2" GFB 5/8" GFB


TOTAL (wet weight) 100.00 100.00 100.00 100.00 100.00

3.2 RAW MATERIALS TRANSPORTATION - GYPSUM BOARD

Gypsum

There are major differences in transportation distances between the sources of gypsum and thegypsum board plants for different gypsum operations. Some of the plants, such as the large CGCoperations in Hagersville, ON, and Domtar’s plants in Caledonia, ON, are built on sites adjoiningtheir sources of gypsum. All other plants receive gypsum from quarries, mines or sources of by-product gypsum from some distance. Some operations use a combination of different sources ofgypsum, most often supplementing natural rock gypsum with synthetic gypsum. Table 3.3provides weighted average distribution of the sources of gypsum for the three geographical regionsas of 1995. As can be seen, natural gypsum is still the dominant source of raw material, with somesynthetic being used both in the Central and East regions. In 1996, further expansion of FGDgypsum utilization is expected in the East region. The contribution of the recycled waste board,both of the internally generated waste and construction waste collected in major metropolitan areasand trucked to the plants, is also indicated. Legislative actions preventing landfilling of gypsumboard construction waste in the Vancouver and Toronto metropolitan areas are the main reason forthe higher “external” recycled content in the West and Central regions.

In the manufacturing process, recycled gypsum board is commingled with other sources of gypsumand handled in the same manner. This source of gypsum does not have to be “extracted”,however, its contribution to the unit factor estimates at all process stages, i.e. to raw materialstransportation and manufacturing, is included.


TABLE 3.3 DISTRIBUTION OF GYPSUM SOURCES BY GEOGRAPHICAL REGION (%)

NaturalGypsum

SyntheticGypsum

Recycled /external

Recycled /internal

West Avg. 86 0 8 6Central Avg. 85 7 4 4East Avg. 81 10 2 7CANADA 85 6 4 5

There is a wide variability in transportation distances, which in some cases also determine the modeof transportation. In the West region, while most of the natural gypsum is moved by truck, onewest coast operation using gypsum from Baja California moves it by ship. Current cost structuredoes not favour rail transport; there is only one plant in this region (and in Canada) transportinggypsum from the quarry to the plant by rail at this time. In the Central region, all the plants areeither adjoining their sources of natural gypsum, in which case they use either electric conveyors ortrucks, or are within economic trucking distance of the quarries. In the East region of the country,where most of the natural gypsum comes from the Atlantic provinces, the distance and actual boardplant location determines the choice of either truck or marine (or marine/truck combination) ofgypsum transportation. All the synthetic and recycled gypsum from external sources is transported,at this point, by truck. Table 3.4 shows weighted average distances by mode of transport for thethree sources of gypsum for the three geographical regions. The favourable location of the Centralregion plants relative to gypsum supplies makes this the most efficient region in terms of rawmaterial transportation energy use, as will be shown in the next section.

TABLE 3.4 WEIGHTED AVERAGE TRANSPORTATION DISTANCES FOR GYPSUM (KM) BY MODE OF TRANSPORT

Natural Gypsum SyntheticGypsum

RecycledGypsum /external

ship rail road total road road

West Avg. 1436 184 274 1894 0 46Central Avg. - - 44 44 34 15East Avg. 656 6 231 893 3 9CANADA 507 47 144 698 18 21


Paper

In estimates of distances and modes of transport of gypsum board paper, two items have to beconsidered:

• transportation of waste paper to the paper mill for recycling, and• transportation of finished paper from the mill to the board producer.

Based on information from one of the two Canadian suppliers, and known locations of other papermills, we assume that an average shipping distance for waste paper to paper mill is 150 km, and thatall shipping is exclusively by truck.

Weighted average shipping distances for the finished gypsum paper are shown in Table 3.5. Insome cases ivory and gray paper are coming from different paper mills, explaining the differencesbetween the two sets of numbers. All gypsum paper is shipped by road transport, with distancesranging from 50 to 2,500 km.

TABLE 3.5 AVERAGE TRANSPORTATION DISTANCES FOR PAPER (KM)

ivory paper gray paper

West Avg. 654 843Central Avg. 457 351East Avg. 835 497CANADA 594 506

Gypsum Fiberboard Raw Materials

Waste paper fibers for reinforcement of GFB are barged along the eastern seaboard from anaverage distance of 1,100 km. Perlite rock is shipped from Greece from an average distance of9,500 km.

Backhaul

Based on our discussions with the producers, we made the following assumption regarding thebackhaul associated with transportation of raw materials:

• gypsum: no backhaul,• waste paper to paper mill: no backhaul,• finished paper (truck): 75% backhaul• waste paper to GFB plant (ship): 75% backhaul,• perlite (ship): 75% backhaul

Appropriate multiples of the transportation distances were used in estimates of the energy andatmospheric emissions unit factors.


3.3 RAW MATERIAL REQUIREMENTS - FINISHING PRODUCTS

Joint compound formulations are similar from one manufacturer to another, from one region of thecountry to another. As indicated in Section 2.5.1, the two main constituents of the ready mixcompounds are finely ground limestone and water, with smaller amounts of talc, mica, specialtyclays and resin binders. The differences between various proprietary formulas are related to minuteadditions of various admixtures and additives, and the details of the formulations are closelyguarded secrets. Nevertheless, the basic formulations are available from raw materials suppliers,companies such as Dow Chemicals, Nacan Products, Reichhold Chemicals, Lorama Chemicals, andothers, and as such are readily available and well known. Typical ready mix joint formulation,based on information from various raw materials suppliers, is shown in Table 3.6, expressed both inper cent (by weight) and in kg per m2 of gypsum board, taking into account standard usage of0.674 kg of compound per 1 m2 of board.

TABLE 3.6 READY MIX JOINT COMPOUNDS GENERIC FORMULATION / AVERAGE RAW MATERIALS USE

Raw Material [ % ] [kg/m2 of gypsum board]

Water 34.6 0.23320Clay 1.7 0.01146Talc 3.8 0.02561Mica 3.5 0.02359Calcium carbonate 52.3 0.35250PVA resin 4.0 0.02696Other 0.1 0.00068

Total 100.0 0.67400

Setting joint compounds, as discussed in Section 2.5.2, are comprised primarily of calcium sulfatehemihydrate (plaster), calcium carbonate (limestone) and mica, with small additions of clays, starch,gels, lime and other chemicals. The type of plaster used for production of setting compounds isoften calcined under different conditions than the stucco for gypsum board production. This so-called “β plaster” is available only from a few calcination plants across North America, and often itis shipped to the joint compound production facilities over some distance. Typical formulation forthe setting joint compound, considering its approximate usage of 0.352 kg/m2 of board, is shown inTable 3.7.

Joint paper tape (see Section 2.5.4) is produced from recycled paper (newspaper, magazines andcardboard) stock, being essentially the same material as the “ivory” bleached paper used for facingof gypsum board. In estimating relevant unit factors, we will therefore use the same assumptionsand numbers as for the “ivory” gypsum paper. As already indicated in Section 2.5, approximateusage of paper tape is about 0.98 m/m2 of gypsum board.


TABLE 3.7 SETTING JOINT COMPOUNDS GENERIC FORMULATION / AVERAGE RAW MATERIALS USE

Raw Material [ % ] [kg/m2 of gypsum board]

Gypsum plaster 48.5 0.17072Calcium carbonate 36.5 0.12848Mica 7.2 0.02534Clay 5.0 0.01760Other 2.8 0.00986

Total 100.0 0.35200

3.4 RAW MATERIALS TRANSPORTATION - JOINT FINISHING PRODUCTS

Joint compound manufacturing plants are located in all three geographical regions of the country.The raw materials, with the exception of plaster, resin binder and chemical additives, are usuallysourced from the local distributors of industrial minerals. However, the particular grades of rawmaterials are often shipped to the local distributor from some distance. Detailed informationregarding the transportation distances are not available. On the basis of rather limited information,we will assume following distances:

TABLE 3.8 ESTIMATED TRANSPORTATION DISTANCES FOR JOINT COMPOUNDS RAW MATERIALS (KM)

West Central E a s t

Water - - -Clay 1200 2000 2000Talc 3500 800 300Mica 2000 2000 2000Calcium carbonate 500 500 100PVA resin 100 100 100Gypsum plaster 1800 2000 2000

Calcium carbonate, plaster and resin binder are usually shipped in bulk, and we will assume nobackhaul, other materials are shipped in bags, and we will assume 100% backhaul. All transport isby truck, with the exception of plaster, 50% of which is shipped by rail in the Central and Eastregions.


For the joint tape raw materials (waste paper) transport, we assume the same average shippingdistance of 150 km by truck as for the gypsum paper for board facings discussed in Section 3.2.Further we assume that finished “ivory” paper is shipped to the joint tape producer for itsconversion the same average distance as the regular “ivory” paper is shipped to the gypsum boardproducers (Table 3.5), with a 75% backhaul.


4.0 ENERGY USE - GYPSUM BOARD

In this section, we explain and present the estimates of energy use developed for all manufacturingstages of the gypsum board production from the raw materials extraction and transportation to thegypsum board processing. For completion, the estimates of energy associated with finished boardtransportation are also shown, although these are fully handled by ATHENATM. All of the results arepresented and discussed in terms of weighted regional averages using the 1995 actual gypsumboard production levels as weights. Various tables show total energy use by region and processstage and we also show the breakdown by energy type because that information is directly relevantto the estimation of atmospheric emissions in a subsequent section of the report.

4.1 RAW MATERIAL EXTRACTION AND TRANSPORTATION

In estimates of energy consumption associated with extraction of gypsum, we had to take a numberof factors into consideration:

• relative distribution of natural, synthetic and recycled gypsum in the three regions,• use of 1.2048 tonnes of gypsum rock (or by-product) for 1 tonne of stucco,• the fact that some primary processing (primary crushing, drying) usually takes

place at the quarry site,• in production of commercial grade synthetic gypsum, the use of steam in the

dewatering system, and the need for some additional power (e.g. for effluenttreatment) that would not have to be used if by-product gypsum were landfilled.1

The differences between the “extraction” energy of natural and synthetic gypsum, as well as thesource of energy in the quarries and mines (diesel fuel (road) vs. electricity), greatly affect theregional weighted averages. We did not receive detailed information from all the quarryingoperations; for the missing quarries we assumed that it takes 0.027 GJ to extract one tonne ofgypsum.2 (Or, multiplying by the factor 1.2048: it takes 0.0325 GJ to extract a sufficient amountof gypsum to produce 1 tonne of stucco.)

Table 4.1 shows weighted average energy consumption for gypsum extraction and primaryprocessing (crushing, drying) at the source site, expressed in GJ per tonne of stucco.

TABLE 4.1 WEIGHTED AVERAGE ENERGY USE FOR GYPSUM EXTRACTION (GJ/TONNE OF STUCCO)

diesel - road coal oil electr ic total

West Avg. 0.0293 0.0000 0.0000 0.0118 0.0411Central Avg. 0.0051 0.0043 0.0000 0.0547 0.0641East Avg. 0.0293 0.0000 0.0057 0.0145 0.0495CANADA 0.0177 0.0021 0.0018 0.0332 0.0548


The use of diesel-road fuel and a portion of the electric power is directly associated with the actualextraction. Coal, oil, and a portion of electric power usage is due to the primary processing. Mostof the mines/quarries process gypsum rock on site prior to its transport to the board manufacturingplants; only few operations ship it “as is” to the plants, where it is crushed. In the absence ofdetailed information, we will assume that all the primary processing is conducted at the extractionsite. In this approach, we will not understate the total energy usage at the gypsum source site,although it will create some distortion in terms of atmospheric emission estimates associated withelectricity use, primarily in the East region. The estimates of electricity use developed in this reportwill be translated in the Sustainable Materials Project calculation model into the mixture of primaryenergy forms used to generate the electricity at the relevant generating facilities and emission factorswill be calculated on that basis. To make this adjustment, the model assumes electricity comes fromthe relevant regional electrical grid. Therefore, when we assume gypsum from Nova Scotia is usedin Quebec, the model will assign those electricity estimates to the Quebec grid and will estimateemissions accordingly. The estimates will likely be different from those that would be madeassuming use of electricity from the Nova Scotia grid. Again, the lack of data precludes our doinganything to avoid this problem and we believe it will in any case be relatively minor in terms of theoverall atmospheric emission estimates for gypsum production.

As an example, the estimates of gypsum extraction energy use, expressed in MJ per square meter offinished 1/2” regular gypsum board on a weighted average basis by region and for Canada as awhole, are shown in Table 4.2. A complete set of tables for all types of gypsum boards is shown inthe summary at the end of this section.

TABLE 4.2 WEIGHTED AVERAGE ENERGY USE FOR GYPSUM EXTRACTION (MJ/M2 OF 1/2" REGULAR GYPSUM BOARD)

diesel - road coal oil electr ic total


Transportation - Gypsum

The transportation energy use estimates were made by applying the following combustion energyfactors from the Research Guidelines:

Mode FuelEnergy Consumed

(MJ/tonne-kilometre)

Truck Diesel - Road 1.18Rail Diesel - Rail 0.49Ship HFO - Marine 0.12


The above factors were applied to the individual raw material tonnages required per tonne of stuccoon a plant-by-plant basis using haul distance estimates provided by the companies, and thosenumbers were later converted to per square meter of finished board, using the formulations asshown in Table 3.1. The distances were adjusted for all modes except conveyors (electricity) toaccount for empty or partial backhauls in accordance with the research guidelines. The weightedregional averages shown in the tables below were then calculated from the individual plantestimates.

TABLE 4.3 WEIGHTED AVERAGE ENERGY USE FOR GYPSUM TRANSPORTATION (GJ/TONNE OF STUCCO)

diesel-road diesel-rail HFO-marine electricity total


TABLE 4.4 WEIGHTED AVERAGE ENERGY USE FOR GYPSUM TRANSPORTATION (MJ/M2 OF 1/2" REGULAR GYPSUM BOARD)

diesel-road diesel-rail HFO-marine electricity total


Transportation - Paper

Weighted regional averages for energy consumption associated with transportation of both thewaste paper as raw material for the paper mill, and of the finished gypsum paper from the paper millto the gypsum board plant, are shown in Tables 4.5 and 4.6.


TABLE 4.5 WEIGHTED AVERAGE ENERGY USE FOR PAPER TRANSPORTATION (GJ/TONNE)

Waste Paper Finished Paper

diesel-road diesel-road HFO-marine total finishedpaper

West Avg. 0.3894 1.1040 0.0000 1.1040Central Avg. 0.3894 0.5959 0.0000 0.5959East Avg. 0.3894 0.7486 0.0088 0.7574CANADA 0.3894 0.7565 0.0021 0.7586

TABLE 4.6 WEIGHTED AVERAGE ENERGY USE FOR PAPER TRANSPORTATION (MJ/M2 OF 1/2" REGULAR GYPSUM BOARD)

Waste Paper Finished Paper



4.2 GYPSUM BOARD MANUFACTURING

As noted in Section 2 during the discussion of the gypsum board production process, boardmanufacturing consists of three separate processes:

• calcination of gypsum to stucco,• gypsum paper manufacturing, and• gypsum board production.

In the development of the energy estimates related to gypsum board manufacturing, we consideredall these three production steps separately, before eventually combining them into the totalmanufacturing energy factors.

Fairly detailed information regarding use of energy in the calcination of gypsum to stucco as wellas for the manufacturing of gypsum board was made available from the three major Canadianproducers for all their plants. Energy consumption estimates were developed and tabulated by boththe processing step and by the type of energy used. Calcination energy consumption data areshown in Tables 4.6 – 4.9.


TABLE 4.6 WEIGHTED AVERAGE ENERGY USE IN STUCCO PREPARATION BY PROCESS STEP (GJ/TONNE OF STUCCO)

secondarycrushing

drying grinding calcination stuccogrinding

stuccotransport

totalstucco

preparation

West Avg. 0.0510 0.6377 0.0250 1.1631 0.0125 0.0476 1.9369Central Avg. 0.0401 0.2893 0.0253 0.9145 0.0030 0.0688 1.3412East Avg. 0.0277 0.5030 0.0201 1.2102 0.0062 0.0464 1.8137CANADA 0.0399 0.4250 0.0240 1.0449 0.0061 0.0584 1.5984

TABLE 4.7 WEIGHTED AVERAGE ENERGY USE IN STUCCO PREPARATION BY PROCESS STEP (MJ/M2 OF 1/2" REGULAR BOARD)

secondarycrushing


stuccotransport

totalstucco

preparation


TABLE 4.8 WEIGHTED AVERAGE ENERGY USE IN STUCCO PREPARATION BY ENERGY FORM (GJ/TONNE OF STUCCO)

natural gas oil diesel electricity total stuccopreparation


TABLE 4.9 WEIGHTED AVERAGE ENERGY USE IN STUCCO PREPARATION BY ENERGY FORM (MJ/M2 OF 1/2" REGULAR BOARD)

natural gas oil diesel electricity total stuccopreparation



Some data were also obtained from one of the Canadian producers of gypsum paper, which wassupplemented with some additional information.3 Nevertheless, there is not sufficient informationavailable to develop regional weighted averages for the gypsum paper production. Therefore wehave assumed that the energy use associated with the paper manufacturing is the same in all threeregions. (Table 4.10) This brings some error into our estimates, however considering that similarprocesses and the same energy sources are used by all gypsum paper producers, this distortion willbe minimal.

TABLE 4.11 WEIGHTED AVERAGE ENERGY USE IN PAPER PRODUCTION BY ENERGY FORM (GJ/TONNE OF PAPER)

natural gas oil electr ic total paper

CANADA 11.6047 0.6108 2.9148 15.1302

TABLE 4.11 WEIGHTED AVERAGE ENERGY USE IN PAPER PRODUCTION BY ENERGY FORM (MJ/M2 OF 1/2" REGULAR BOARD)


CANADA 5.4720 0.2880 1.3744 7.1344

Energy associated with the production of gypsum board itself, as per information provided byCanadian gypsum board producers, is shown, as an example, for 1/2" regular gypsum board, inTable 4.12.

TABLE 4.12 WEIGHTED AVERAGE ENERGY USE IN BOARD MANUFACTURING BY ENERGY FORM (MJ/M2 OF 1/2" REGULAR BOARD)

natural gas oil electr ictotal board

manufacturingenergy


Total energy use associated with the three process steps of 1/2" thick regular gypsum boardmanufacturing is summarized in Tables 4.13 and 4.14.


TABLE 4.13 TOTAL WEIGHTED AVERAGE ENERGY USE ASSOCIATED WITH PRODUCTION OF GYPSUM BOARD BY PROCESS STEP

(MJ/M2 OF 1/2" REGULAR BOARD)

paperproduction

stuccoproduction

boardproduction

total energy


TABLE 4.14 TOTAL WEIGHTED AVERAGE ENERGY USE ASSOCIATED WITH PRODUCTION OF GYPSUM BOARD BY ENERGY FORM

(MJ/M2 OF 1/2" REGULAR BOARD)

diesel - road natural gas oil electr ic total energy


Detailed tables summarizing energy usage for ten types of gypsum boards under consideration, byprocess stage and region as well as by energy form and region, are shown at the end of this section,in Tables 4.25 to 4-44.

4.3 FINISHED GYPSUM BOARD TRANSPORTATION

The last energy use category covers the transportation of finished gypsum board products fromgypsum board plants to Canadian market distribution centres.

As in the case of raw material transportation, information about transportation distances, modes andgeographical market distribution was provided by the three major gypsum board producers for alltheir plants. Based on our knowledge of the Canadian gypsum board markets, some assumptionshad to be made regarding the relative share of the market between the various producers, as well asto include the remaining minor regional or specialty manufacturers. The Research Guidelines statethat finished product transportation data should be provided in kilometres by mode of transport foraverage haul distances to Halifax, Montreal, Toronto, Winnipeg, Calgary and Vancouver from therelevant production points. The Guidelines further noted that “relevant production points” wouldbe the facilities typically serving each of the cities.

Based on the information received from the gypsum board manufacturers, we concluded:


• Vancouver is served by local plants by truck,• Calgary is served 90% by the plants located in Alberta by truck, with 10% of the

board shipped by rail from the Central region,• Winnipeg is similarly served by local plants (85%), and 15% by rail from the

Central region,• Toronto is supplied exclusively by truck from local operations,• Montreal is served mainly (80%) by truck from local plants, with the remaining

20% shipped also by truck from the Central region, and• Halifax is supplied by plants located in Atlantic provinces (40%), either by truck

or by ship, as well as by rail from either the Central region or the Quebec part ofto East region.

The weighted average transportation distances by mode shown in Table 4.15 were then developedusing the distances of each plant from the designated cities. Following discussions with the boardproducers, we assumed that only 20% backhaul is involved in truck transportation, whereas 100%backhaul is the rule for both the rail and the marine transportation of the finished board. Thesebackhaul assumptions are already reflected in the distance numbers in the Table 4.15.

TABLE 4.15 WEIGHTED AVERAGE TRANSPORTATION DISTANCES BY MODE FOR FINISHED GYPSUM BOARD (KM)

Average Distances & Transport Mode

Truck Rail Ship

Vancouver 90 0 0Calgary 225 300 0Winnipeg 90 400 0Toronto 153 0 0Montreal 288 0 0Halifax 279 847.5 110

Transport factors [MJ/tonne-km] 1.18 0.49 0.12

note: appropriate backhaul factors included in the distances

The ATHENATM computer model calculates the energy consumption associated with the finishedproducts transportation from the plant gate to the market, taking into consideration distances andtransport mode. Here, just for illustration, we show the energy estimates (Tables 4.16 and 4.17 for1/2" regular board). The distances by mode, as per Table 4-15, were multiplied by the relevanttonne-kilometre energy consumption figures.

We should emphasize that the averages in Tables 4.15, 4.16 and 4.17 only reflect where gypsumboard is produced and how it is moved. They do not reflect gypsum board consumption levels inany of the cities. Both tables can be interpreted by thinking in terms of the embodied finaltransportation mileage and energy in a representative or average tonne of board (or square meter ofboard) landed in any one of the six cities.


TABLE 4.16 WEIGHTED AVERAGE TRANSPORTATION ENERGY FOR FINISHED GYPSUM BOARD (GJ/ TONNE)

Truck Rail Ship Total

diesel-road diesel-rail HFO-marine

Vancouver 0.1062 0.0000 0.0000 0.1062Calgary 0.2655 0.1470 0.0000 0.4125Winnipeg 0.1062 0.1960 0.0000 0.3022Toronto 0.1805 0.0000 0.0000 0.1805Montreal 0.3398 0.0000 0.0000 0.3398Halifax 0.3292 0.4153 0.0132 0.7577

TABLE 4.17 WEIGHTED AVERAGE TRANSPORTATION ENERGY FOR FINISHED GYPSUM BOARD (MJ/ M2 OF 1/2" REGULAR BOARD)

Truck Rail Ship Total

diesel-road diesel-rail HFO-marine

Vancouver 0.8563 0.0000 0.0000 0.8563Calgary 2.1408 1.1853 0.0000 3.3261Winnipeg 0.8563 1.5804 0.0000 2.4367Toronto 1.4557 0.0000 0.0000 1.4557Montreal 2.7402 0.0000 0.0000 2.7402Halifax 2.6546 3.3485 0.1064 6.1095

We have omitted national averages from Tables 4.15 to 4.17 because national averages would beunduly distorted by the absence of any weights to take into account relative consumption levels indifferent cities and regions. If consumption is not taken into account, the high transportationenergy associated with moving gypsum board to cities like Halifax or Calgary would be given toomuch implicit weight when calculating national averages. In contrast, the earlier sub-sections dealstrictly with aspects of production, and actual production capacities provide an adequate weightingmechanism even at the national level. The omission of national averages at this stage, andsubsequently, has no bearing in terms of our ultimate focus which is on unit factors for gypsumboard delivered to the individual cities.

4.4 GYPSUM BOARD - ENERGY SUMMARY

This section summarizes all the preceding energy estimates associated with the production ofgypsum board by processing stage and by energy form in MJ/m2 of board. The summaries arepresented for a “cradle to gate” LCA used by the ATHENATM model, as well as, for illustration, fora “cradle to market” LCA. Tables 4.25 and 4.26 cover 1/2" regular gypsum board discussed indetail above. The following tables (4.27 to 4.40) provide the same summary information for othercommon types and thicknesses of gypsum board, as selected and discussed in Section 2.


The relative distribution of the energy used in production of gypsum board by the process step isshown as a percentage of the total energy use for the six cities under consideration in Table 4.18and graphically in Fig. 4.1 for 1/2" regular board as an example. For other types of board, relativeenergy distribution would be similar. The total manufacturing stage (consisting of the paperproduction, gypsum calcination and board production itself) is obviously the most significant as farenergy consumption is concerned, varying between different areas in the 73% to 89% range. Thisis followed by the raw materials transportation, showing a rather wide range from about 6% to 21%.This wide range is the result of some plants producing board right at the gypsum source site,whereas other board operations have to ship gypsum from thousands of kilometres away. Gypsumextraction and the initial on-site processing represents the lowest energy expense of the fourprocessing stages.

Of the three manufacturing steps, the gypsum board manufacturing constitutes the highest share ofthe total manufacturing energy use at around 50%, followed by gypsum calcination (around 30%)and paper production (approximately 20%). This relative distribution of the manufacturing energyuse is shown for 1/2" regular gypsum board in Table 4.19 and graphically illustrated in Fig. 4.2.

TABLE 4.18 PER CENT OF ENERGY USE IN GYPSUM BOARD PRODUCTION[1/2" BOARD] BY PROCESS STAGE (%)

Gypsum Total RM Total Board TOTALExtraction Transportation Manufacturing Transportation

Vancouver 0.53 20.96 76.80 1.71 100.00Calgary 0.51 19.98 73.20 6.31 100.00Winnipeg 1.09 5.71 86.83 6.38 100.00Toronto 1.11 5.86 89.12 3.91 100.00Montreal 0.68 13.51 79.98 5.83 100.00Halifax 0.64 12.61 74.63 12.12 100.00

TABLE 4.19 PER CENT OF ENERGY USE IN MANUFACTURING STAGES OF GYPSUM BOARD PRODUCTION [1/2" BOARD] BY PROCESS STAGE (%)

PaperManufacturing

StuccoManufacturing

BoardManufacturing

TotalManufacturing

West Region 18.50 32.50 49.00 100.00Central Region 21.51 26.17 52.33 100.00East Region 18.97 31.21 49.83 100.00


Vancouver Calgary Winnipeg Toronto Montreal Halifax0

20

40

60

80

100

Extraction

RM Transport

Manufacturing

Board Transport

C i t y

%

of

tota

l e

ne

rgy

u

se

Fig. 4.1: Breakdown of Energy Use in Gypsum Board Production [1/2" Board]by Process Stage (%)

Paper Stucco Board0

10

20

30

40

50

60

West

Central

East

Manufacturing of

%

of

tota

l m

an

ufa

ctu

rin

g

en

erg

y

Fig 4.2Breakdown of Energy Use in Manufacturing Stages of Gypsum Board Production [1/2" Board] by Process Stage (%)


4.5 ENERGY USE IN GYPSUM FIBERBOARD (GFB) PRODUCTION

All of the previous parts of this section discussed primarily conventional, paper faced gypsumboards. Most of what was said is also valid for paperless gypsum fiberboard (GFB), althoughthere are some substantial differences in the formulations and in the raw materials used, as well asin the manufacturing process itself. GFB is manufactured only in one location in all of NorthAmerica at this time, in Louisiana-Pacific’s plant in Nova Scotia, and this was taken intoconsideration for both the raw materials and the finished product transportation. As themanufacturer decided not to provide any information for this study, some additional assumptionshad to be made based on our knowledge of the process and the published information.

Raw Materials Extraction

In GFB production only locally available natural gypsum is used (together with 10% internal wasterecycling). Gypsum extraction energy for the Eastern region, expressed per tonne of stucco, wasadjusted accordingly. For perlite, the other industrial mineral used, we assumed extraction energyof 0.027 GJ/tonne of rock, in the form of diesel-road fuel, and the electrical energy input based onthe gypsum rock extraction.

TABLE 4.20 WEIGHTED AVERAGE EXTRACTION ENERGY FOR GYPSUM AND PERLITE USED IN 1/2" GFB PRODUCTION

Gypsum extraction Perlite extraction Total extraction

diesel electric totalgypsum

diesel electric totalperlite

diesel electric TOTALRMs

[GJ/tonne of stucco] [GJ/tonne of perlite]

0.0305 0.0117 0.0423 0.0270 0.0108 0.0378

[MJ/m2 of board] [MJ/m2 of board] [MJ/m2 of board]

0 . 2 1 7 5 0 . 0 8 3 4 0 . 3 0 0 8 0 . 0 3 5 9 0 . 0 1 4 4 0 . 0 5 0 3 0 . 2 5 3 4 0 . 0 9 7 7 0 . 3 5 1 1

Raw Materials Transportation

Specific conditions related to the GFB operation were considered. These include rail transportationof the locally quarried gypsum, marine transportation of the perlite rock from overseas, and both thelocal transportation by truck of the collected waste paper and its shipping by barge from thesecollection points along the Eastern seaboard.4 It was assumed that other raw materials are locallyavailable in Nova Scotia, and supplied by truck. Appropriate backhaul assumptions were made aswell. The resulting energy estimates for 1/2" GFB are shown in Table 4.21.


TABLE 4.21 WEIGHTED AVERAGE ENERGY USE FOR 1/2" GFB RAW MATERIALS TRANSPORTATION

Gypsum Waste Paper Perl i te OtherRMs

RMs Transport

diesel-rail

diesel-road

HFO-marine

wastepapertotal

HFO-marine

dieselroad

dieselroad

diesel-rail

HFO-marine

TOTAL

[GJ/tonneof stucco]

[GJ/tonne]

0.0413 0.3894 0.1650 0.5544 1.4250 0.4720

[MJ/m2 of board]

0 . 2 8 2 8 0 . 5 9 2 2 0 . 2 5 0 9 0 . 8 4 3 1 1 . 8 9 6 1 0 . 1 3 0 6 0 . 7 2 2 7 0 . 2 8 2 8 2 . 1 4 7 1 3 . 1 5 2 6

GFB Manufacturing

In GFB production four separate manufacturing steps have to be considered:

• gypsum calcination,• perlite expansion,• paper defiberization, and• board production.

For gypsum calcination we used the weighted average energy estimate [GJ/tonne of stucco]developed for the East region in Table 4.6. For the rather energy-intensive perlite expansion, W.R.Grace provided an average estimate of 3500 BTU/lb (= 8.1337 GJ/tonne).5 As far as the paperdefiberization is concerned, we assumed that this is covered by the electrical energy input into thepaper production from Table 4.11. Finally, for the board manufacturing itself, we used factors(developed in a client confidential GFB technical study) of 0.9555 for fuel use and 3.15 for powerconsumption for production of GFB vs. conventional gypsum board of the same thickness.6 Theresulting energy estimates for manufacturing of 1/2" GFB are presented in Tables 4.22 and 4.23.

TABLE 4.22 AVERAGE ENERGY USE IN MANUFACTURING OF 1/2" GFB BY ENERGY FORM

Energy natural gas oil diesel-road electricity TOTAL

[MJ/m2 of board] 3 3 . 7 6 0 9 3 . 6 9 5 6 2 . 6 8 7 5 6 . 9 5 0 4 47 .0943


TABLE 4.23 AVERAGE ENERGY USE IN MANUFACTURING OF 1/2" GFB BY PROCESS STEP

Gypsumcalcination

Paperdefiberization

Perl i teexpansion

Boardmanufacturing

TOTALmanufacturing

[GJ/tonne ofstucco]

[GJ/tonne of paper] [GJ/tonne of perlite]

1.8137 2.9148 8.1337

[MJ/m2 of board]

1 2 . 9 1 2 9 4 . 4 3 2 5 10 .8229 18 .9259 47 .0943

Finished GFB Transportation

GFB board produced in L-P’s Nova Scotia plant is intended mainly for the markets along theEastern seaboard of the U.S.A. Nevertheless, it is also available through local distributors acrossCanada. In estimating energy embodied in finished GFB transportation, we assumed that toHalifax it is shipped by truck (20% backhaul) and to the rest of the country by rail (100%backhaul). Using the appropriate distances between Port Hawkesbury and the six regional citiesunder consideration

[km] [mode]

Vancouver 5840 railCalgary 4878 railWinnipeg 3538 railToronto 1816 railMontreal 1276 railHalifax 360 road

The ATHENATM model calculates the energy factors associated with the GFB point of manufactureto the market. In the study, we provided the finished product transport energy estimates, based onthe above distances and transport modes combined with the relevant transport factors from Table4.15, just for illustration:


TABLE 4.24 ENERGY EMBODIED IN TRANSPORTATION OF FINISHED 1/2" GFB

diesel-road diesel-rail

[GJ/tonne]

Vancouver - 2.8616Calgary - 2.3902Winnipeg - 1.7336Toronto - 0.8898Montreal - 0.6252Halifax 0.4248 -

[GJ/m2 of board]

Vancouver - 32 .0235Calgary - 26 .7484Winnipeg - 19 .4005Toronto - 9 . 9 5 8 0Montreal - 6 . 9 9 6 9Halifax 4 . 7 5 3 8 -

GFB Energy Summary

Total energy estimates associated with the production of 1/2" and 5/8" thick gypsum fiberboard byprocessing stage and by energy form in MJ/m2 of board are summarized in Tables 4.41 to 4.44.

REFERENCES

1. Communication from R.S. Daly, Ontario Hydro, dated February 27, 1996.2. Canadian Industry Program for Energy Conservation (CIPEC), Ministry of Energy, Mines and

Resources Canada, 1989.3. “Gypsum Board Systems: Technical Report”, Topic I-9250, AIA Environmental Resource

Guide, July 1993.4. G. Natus, “Gypsum Fiberboard Production in Nova Scotia”, Proceedings of the 2nd

International Conference on Inorganic-Bonded Wood and Fiber Composite Materials,Moscow, ID, October 15-17, 1990, pp.85-87.

5. Oral communication from B. Colbert, W.R. Grace Construction Products Division, August 9,1996

6. “Gypsum Fiberboard (GFB): Technical Assessment Report”, Venta, Glaser & Associates,confidential client report, October 1991/July 1994.

The AthenaTM Project:Gypsum Board and Associated Finishing Products 4- 16

TABLE 4.25 ENERGY USE IN 1/2" REGULAR GYPSUM BOARD BY PROCESS STAGE AND REGION [MJ/M2]

Gypsum RMs Manufacturing Total Board TotalExt ract . Transport Paper Stucco Board Total

Manufact .to Gate Transport to Market

West Vancouver 0.2662 10.5276 7.1344 12.5352 18.8984 38.5680 49 .3618 0.8563 50.2181Calgary 3.3261 52.6878

Central Winnipeg 0.4147 2.1800 7.1344 8.6797 17.3569 33.1710 35 .7657 2.4367 38.2024Toronto 1.4557 37.2214

E a s t Montreal 0.3203 6.3555 7.1344 11.7375 18.7404 37.6124 44 .2882 2.7402 47.0284Halifax 6.1095 50.3977

TABLE 4.26A CRADLE TO GATE ENERGY USE IN 1/2" REGULAR GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]

Diesel-road Diesel-rail HFO-marine

Natural gas Coal Oi l Electricity TotalTo Gate

West 6.6221 1.4079 2.6873 28.6079 0.0000 7.1131 2.9235 49 .3618Central 3.3051 0.0000 0.0000 25.1897 0.0279 4.1587 3.0843 35 .7657E a s t 7.7562 0.0000 1.2317 21.2130 0.0000 11.1958 2.8916 44 .2882

TABLE 4.26B CRADLE TO MARKET ENERGY USE IN 1/2" REGULAR GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]


Natural gas Coal Oi l Electricity TotalTo Market

West Vancouver 7.4784 1.4079 2.6873 28.6079 0.0000 7.1131 2.9235 50 .2181Calgary 8.7629 2.5932 2.6873 28.6079 0.0000 7.1131 2.9235 52 .6878

Central Winnipeg 4.1615 1.5804 0.0000 25.1897 0.0279 4.1587 3.0843 38 .2024

Toronto 4.7609 0.0000 0.0000 25.1897 0.0279 4.1587 3.0843 37 .2214

E a s t Montreal 10.4964 0.0000 1.2317 21.2130 0.0000 11.1958 2.8916 47 .0284

Halifax 10.4107 3.3485 1.3381 21.2130 0.0000 11.1958 2.8916 50 .3977


TABLE 4.27 ENERGY USE IN 1/2" TYPE X GYPSUM BOARD BY PROCESS STAGE AND REGION [MJ/M2]


Manufact . to Gate Transport to Market




TABLE 4.28A CRADLE TO GATE ENERGY USE IN 1/2" TYPE X GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]


Natural gas Coal Oi l Electricity Totalto Gate

West 6.7165 1.4378 2.7443 28.5468 0.0000 7.1634 2.8871 49 .4958Central 3.3449 0.0000 0.0000 25.0608 0.0284 4.1732 3.0524 35 .6597East 7.8856 0.0000 1.2575 21.0772 0.0000 11.2551 2.8533 44 .3287

TABLE 4.28B CRADLE TO MARKET ENERGY USE IN 1/2" TYPE X GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]


Natural gas Coal Oi l Electricity Totalto Market



Toronto 4.8227 0.0000 0.0000 25.0608 0.0284 4.1732 3.0524 37 .1375

E a s t Montreal 10.6673 0.0000 1.2575 21.0772 0.0000 11.2551 2.8533 47 .1104

Halifax 10.5804 3.3992 1.3656 21.0772 0.0000 11.2551 2.8533 50 .5308


TABLE 4.29 ENERGY USE IN 1/2" MR GYPSUM BOARD BY PROCESS STAGE AND REGION [MJ/M2]





East Montreal 0.3635 7.1534 7.3344 13.3175 18.7404 39.3923 46 .9092 3.0724 49.9816Halifax 6.8500 53.7592

TABLE 4.30A CRADLE TO GATE ENERGY USE IN 1/2" MR GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]




TABLE 4.30B CRADLE TO MARKET ENERGY USE IN 1/2" MR GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]





Toronto 5.3327 0.0000 0.0000 26.0572 0.0316 4.3393 3.3051 39 .0660

E a s t Montreal 11.8154 0.0000 1.3970 22.0363 0.0000 11.6610 3.0718 49 .9816

Halifax 11.7194 3.7543 1.5164 22.0363 0.0000 11.6610 3.0718 53 .7592


TABLE 4.31 ENERGY USE IN 5/8" REGULAR GYPSUM BOARD BY PROCESS STAGE AND REGION [MJ/M2]

Gypsum RMs Manufacturing Total Board TotalExt ract . Transport Paper Stucco Board Total to





TABLE 4.32A CRADLE TO GATE ENERGY USE IN 5/8" REGULAR GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]



West Vancouver 8.4443 1.8394 3.5109 34.9391 0.0000 8.9906 3.3921 61 .1164Central Winnipeg 4.1814 0.0000 0.0000 30.4860 0.0364 5.2023 3.6051 43 .5112E a s t Halifax 9.9753 0.0000 1.6079 25.4966 0.0000 14.1181 3.3472 54 .5451

TABLE 4.32B CRADLE TO MARKET ENERGY USE IN 5/8" REGULAR GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]





Toronto 6.0385 0.0000 0.0000 30.4860 0.0364 5.2023 3.6051 45 .3684

E a s t Montreal 13.4711 0.0000 1.6079 25.4966 0.0000 14.1181 3.3472 58 .0409

Halifax 13.3619 4.2718 1.7437 25.4966 0.0000 14.1181 3.3472 62 .3393


TABLE 4.33 ENERGY USE IN 5/8" TYPE X GYPSUM BOARD BY PROCESS STAGE AND REGION [MJ/M2]


manufact.to Gate Transport to Market




TABLE 4.34A CRADLE TO GATE ENERGY USE IN 5/8" TYPE X GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]




TABLE 4.34B CRADLE TO MARKET ENERGY USE IN 5/8" TYPE X GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]





Toronto 6.1191 0.0000 0.0000 30.4409 0.0369 5.2187 3.5942 45 .4098

E a s t Montreal 13.6668 0.0000 1.6308 25.4453 0.0000 14.1740 3.3306 58 .2475

Halifax 13.5552 4.3631 1.7695 25.4453 0.0000 14.1740 3.3306 62 .6377


TABLE 4.35 ENERGY USE IN 5/8" MR GYPSUM BOARD BY PROCESS STAGE AND REGION [MJ/M2]

Gypsum RMs Manufacturing Total Board TotalExt rac . Transport Paper Stucco Board Total





TABLE 4.36A CRADLE TO GATE ENERGY USE IN 5/8" MR GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]




TABLE 4.36B CRADLE TO MARKET ENERGY USE IN 5/8" MR GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]





Toronto 6.7052 0.0000 0.0000 31.6174 0.0405 5.4106 3.8924 47 .6662

E a s t Montreal 14.9826 0.0000 1.7902 26.5792 0.0000 14.6399 3.5898 61 .5818

Halifax 14.8606 4.7690 1.9418 26.5792 0.0000 14.6399 3.5898 66 .3804


TABLE 4.37 ENERGY USE IN 5/16" MOBILE HOME GYPSUM BOARD BY PROCESS STAGE AND REGION [MJ/M2]






TABLE 4.38A CRADLE TO GATE ENERGY USE IN 5/16" MOBILE HOME GYPSUM BOARD BY ENERGY FORM AND REGION [MJ/M2]



West Vancouver 4.9101 0.9945 1.8983 20.8227 0.0000 4.8059 2.4853 35 .9168Central Winnipeg 2.4880 0.0000 0.0000 18.4263 0.0197 2.8220 2.6032 26 .3592E a s t Halifax 5.6559 0.0000 0.8714 15.9141 0.0000 7.3922 2.4583 32 .2919

TABLE 4.38B CRADLE TO MARKET ENERGY USE IN 5/16" MOBILE HOME BOARD BY ENERGY FORM AND REGION [MJ/M2]




Central Winnipeg 3.1108 1.1494 0.0000 18.4263 0.0197 2.8220 2.6032 28 .1313Toronto 3.5467 0.0000 0.0000 18.4263 0.0197 2.8220 2.6032 27 .4179

E a s t Montreal 7.6487 0.0000 0.8714 15.9141 0.0000 7.3922 2.4583 34 .2847Halifax 7.5865 2.4352 0.9488 15.9141 0.0000 7.3922 2.4583 36 .7351


TABLE 4.39 ENERGY USE IN 1" SHAFTLINER BOARD BY PROCESS STAGE AND REGION [MJ/M2]






TABLE 4.40A CRADLE TO GATE ENERGY USE IN 1" SHAFTLINER BOARD BY ENERGY FORM AND REGION [MJ/M2]




TABLE 4.40B CRADLE TO MARKET ENERGY USE IN 1" SHAFTLINER BOARD BY ENERGY FORM AND REGION [MJ/M2]





Toronto 10.8918 0.0000 0.0000 47.5128 0.0683 8.6214 5.4582 72 .5524

E a s t Montreal 24.7467 0.0000 3.0161 39.4103 0.0000 23.6545 4.9361 95 .7637

Halifax 24.5443 7.9145 3.2677 39.4103 0.0000 23.6545 4.9361 103 .7274


TABLE 4.41 ENERGY USE IN 1/2" GFB BY PROCESS STAGE AND REGION [MJ/M2]

RMs RMs Manufacturing Total Board TotalExt ract . Transport Paper Perl i te Stucco Board Total

Manufactto Gate Transport t o

Market

West Vancouver 0.3511 3.1526 4.4325 10.8229 12.9129 18.9259 47.0943 50 .5980 32.0235 82.6215Calgary 0.3511 3.1526 4.4325 10.8229 12.9129 18.9259 47.0943 50 .5980 26.7484 77.3464

Central Winnipeg 0.3511 3.1526 4.4325 10.8229 12.9129 18.9259 47.0943 50 .5980 19.4005 69.9985Toronto 0.3511 3.1526 4.4325 10.8229 12.9129 18.9259 47.0943 50 .5980 9.9580 60.5560

E a s t Montreal 0.3511 3.1526 4.4325 10.8229 12.9129 18.9259 47.0943 50 .5980 6.9969 57.5949Halifax 0.3511 3.1526 4.4325 10.8229 12.9129 18.9259 47.0943 50 .5980 4.7538 55.3518

TABLE 4.42A CRADLE TO GATE ENERGY USE IN 1/2" GFB BY ENERGY FORM AND REGION [MJ/M2]


NaturalG a s

Oil Electricity Totalto Gate

West 3.6636 0.2828 2.1471 33.7609 3.6956 7.0482 50 .5980Central 3.6636 0.2828 2.1471 33.7609 3.6956 7.0482 50 .5980E a s t 3.6636 0.2828 2.1471 33.7609 3.6956 7.0482 50 .5980

TABLE 4.42B CRADLE TO MARKET ENERGY USE IN 1/2" GFB BY ENERGY FORM AND REGION [MJ/M2]


NaturalG a s

Oil Electricity Totalto Market

West Vancouver 3.6636 32.3063 2.1471 33.7609 3.6956 7.0482 82 .6215Calgary 3.6636 27.0312 2.1471 33.7609 3.6956 7.0482 77 .3464

Central Winnipeg 3.6636 19.6833 2.1471 33.7609 3.6956 7.0482 69 .9985Toronto 3.6636 10.2408 2.1471 33.7609 3.6956 7.0482 60 .5560

E a s t Montreal 3.6636 7.2797 2.1471 33.7609 3.6956 7.0482 57 .5949Halifax 8.4174 0.2828 2.1471 33.7609 3.6956 7.0482 55 .3518


TABLE 4.43 ENERGY USE IN 5/8" GFB BY PROCESS STAGE AND REGION [MJ/M2]

RMs RMs Manufacturing Total Board TotalExt ract . Transport Paper Perl i te Stucco Board Total

Manufactto Gate Transport t o

Market

West Vancouver 0.4357 3.9117 5.4999 13.4291 16.0224 23.6574 58.6088 62 .9562 39.9944 102.9506Calgary 0.4357 3.9117 5.4999 13.4291 16.0224 23.6574 58.6088 62 .9562 33.4063 96.3625

Central Winnipeg 0.4357 3.9117 5.4999 13.4291 16.0224 23.6574 58.6088 62 .9562 24.2295 87.1857Toronto 0.4357 3.9117 5.4999 13.4291 16.0224 23.6574 58.6088 62 .9562 12.4366 75.3928

E a s t Montreal 0.4357 3.9117 5.4999 13.4291 16.0224 23.6574 58.6088 62 .9562 8.7385 71.6947Halifax 0.4357 3.9117 5.4999 13.4291 16.0224 23.6574 58.6088 62 .9562 5.9371 68.8933

TABLE 4.44A CRADLE TO GATE ENERGY USE IN 5/8" GFB BY ENERGY FORM AND REGION [MJ/M2]


NaturalG a s

Oil Electricity Totalto Gate

West Vancouver 4.5458 0.3509 2.6641 42.0512 4.5854 8.7588 62 .9562Central Winnipeg 4.5458 0.3509 2.6641 42.0512 4.5854 8.7588 62 .9562E a s t Halifax 4.5458 0.3509 2.6641 42.0512 4.5854 8.7588 62 .9562

TABLE 4.44B CRADLE TO MARKET ENERGY USE IN 5/8" GFB BY ENERGY FORM AND REGION [MJ/M2]


NaturalG a s

Oil Electricity Totalto Market

West Vancouver 4.5458 40.3453 2.6641 42.0512 4.5854 8.7588 102 .9506Calgary 4.5458 33.7572 2.6641 42.0512 4.5854 8.7588 96 .3625

Central Winnipeg 4.5458 24.5804 2.6641 42.0512 4.5854 8.7588 87 .1857Toronto 4.5458 12.7875 2.6641 42.0512 4.5854 8.7588 75 .3928

E a s t Montreal 4.5458 9.0894 2.6641 42.0512 4.5854 8.7588 71 .6947Halifax 10.4829 0.3509 2.6641 42.0512 4.5854 8.7588 68 .8933


5.0 ENERGY USE - FINISHING PRODUCTS

In this section, we provide the estimates of energy consumption for the raw materials extraction andtransportation, manufacturing and finished products transportation of the gypsum board jointfinishing compounds and joint paper tape. All of the estimates are developed essentially in thesame manner as the energy unit factors estimated in Section 4 for gypsum board.

5.1 JOINT FINISHING PRODUCTS RAW MATERIAL EXTRACTION AND TRANSPORTATION

In Section 3.3 generic formulations for both ready mix drying and dry setting compounds weregiven. While both types of joint compounds are comprised of a number of different raw materials,most of these (limestone, mica, talc, gypsum and clays) are industrial minerals quarried in open pits.We will therefore assume that it takes 0.027 GJ/tonne1 for extraction of these materials, and that allthis energy is in the form of diesel fuel (road), as specified in the Sustainable Materials ProjectResearch Guidelines. For gypsum, we take into account the fact that 1.2048 tonnes of gypsum areneeded to produce 1 tonne of calcined plaster. (For water and PVA resin we assume no embodiedextraction energy, whereas for “other” materials we assume the same energy loading as for theother industrial minerals.) As no detailed regional data are available, we will assume that the sameamount of energy is required to extract the required quantities of raw materials all across Canada.Table 5.1 shows average energy consumption for applicable industrial minerals and their primaryon site processing for both types of joint compounds, expressed in MJ/kg of compound as well asin MJ/m2 of board (typical usage of joint compound per m2 of gypsum board was shown inSection 2.5).

TABLE 5.1 AVERAGE ENERGY USE FOR JOINT COMPOUNDS RAW MATERIALS EXTRACTION

Ready Mix Compound Setting (Dry) Compound

[MJ/kg ofcompound]

[MJ/m2 of board] [MJ/kg ofcompound]

[MJ/m2 of board]

Water 0.00000 0.00000 - -Calcium carbonate 0.01412 0.00952 0.00986 0.00347Gypsum plaster - - 0.01578 0.00555Mica 0.00095 0.00064 0.00194 0.00068Talc 0.00103 0.00069 - -Clay 0.00046 0.00031 0.00135 0.00048PVA resin 0.00000 0.00000 - -Other 0.00003 0.00002 0.00076 0.00027

Total 0 .01658 0 .01117 0 .02968 0 .01045


Joint Compounds Raw Materials Transportation

The transportation energy use estimates were made by applying the appropriate combustion energyfactors shown earlier (Section 4.1) to the formulations for both the ready mix and setting jointcompounds, as shown in Tables 3.6 and 3.7 respectively, taking into account the average rawmaterials transportation distances, backhaul assumptions, and modes of transport (Table 3.8).Resulting estimates of energy usage associated with the transportation of the ready mix jointcompounds raw materials are shown in Tables 5.2 and 5.3, and of the setting compounds in Tables5.4 and 5.5.

TABLE 5.2 AVERAGE ENERGY USE FOR READY MIX JOINT COMPOUNDS RAW MATERIALS TRANSPORTATION (MJ/KG OF COMPOUND)

West Region Central Region East Region

Water 0.00000 0.00000 0.00000Clay 0.02285 0.03808 0.03808Talc 0.14896 0.03405 0.01277Mica 0.07840 0.07840 0.07840Calcium carbonate 0.58576 0.58576 0.11715PVA resin 0.00896 0.00896 0.00896Other 0.00280 0.00280 0.00280

Total 0 .84773 0 .74805 0 .25816

note: all energy in form of diesel (road)

TABLE 5.3 AVERAGE ENERGY USE FOR READY MIX JOINT COMPOUNDS RAW MATERIALS TRANSPORTATION (MJ/M2 OF BOARD)


Water 0.00000 0.00000 0.00000Clay 0.01540 0.02567 0.02567Talc 0.10040 0.02295 0.00861Mica 0.05284 0.05284 0.05284Calcium carbonate 0.39480 0.39480 0.07896PVA resin 0.00604 0.00604 0.00604Other 0.00189 0.00189 0.00189

Total 0 .57137 0 .50418 0 .17400

note: all energy in form of diesel (road)


TABLE 5.4 AVERAGE ENERGY USE FOR SETTING JOINT COMPOUNDS RAW MATERIALS TRANSPORTATION (MJ/KG OF COMPOUND)


total(diesel road)

totaldiesel road diesel rail


Gypsum plaster 1.95552 1.56170 1.08640 0.47530 1.56170 1.08640 0.47530Calcium carbonate 0.40880 0.40880 0.40880 0.00000 0.08176 0.08176 0.00000Mica 0.16128 0.16128 0.16128 0.00000 0.16128 0.16128 0.00000Clay 0.06720 0.11200 0.11200 0.00000 0.11200 0.11200 0.00000Other 0.07840 0.07840 0.07840 0.00000 0.07840 0.07840 0.00000

Total 2 .67120 2 .32218 1 .84688 0 .47530 1 .99514 1 .51984 0 .47530

TABLE 5.5 AVERAGE ENERGY USE FOR SETTING JOINT COMPOUNDS RAW MATERIALS TRANSPORTATION (MJ/M2 OF BOARD)


total(diesel road)



Gypsum plaster 0.68834 0.54972 0.38241 0.16731 0.54972 0.38241 0.16731Calcium carbonate 0.14390 0.14390 0.14390 0.00000 0.02878 0.02878 0.00000Mica 0.05677 0.05677 0.05677 0.00000 0.05677 0.05677 0.00000Clay 0.02365 0.03942 0.03942 0.00000 0.03942 0.03942 0.00000Other 0.02760 0.02760 0.02760 0.00000 0.02760 0.02760 0.00000

Total 0 .94026 0 .81741 0 .65010 0 .16731 0 .70229 0 .53498 0 .16731

Joint Paper Tape Raw Materials Transportation

As already noted, joint paper tape is essentially the same product as “ivory” paper for gypsumboard facings. The average energy consumption associated with the transportation of waste paperas raw material for the paper mill and of the paper stock from the paper mill to the producer to beconverted to the joint tape is therefore estimated in a similar manner as for the “ivory” paper forthe board production in Section 4.1. Table 5.6 provides resulting estimates in GJ per tonne ofpaper.


TABLE 5.6 AVERAGE ENERGY USE FOR JOINT PAPER TAPE RAW MATERIALS TRANSPORTATION (GJ/TONNE OF PAPER)

Waste Paper Finished Paper for Joint Tape


West Avg. 0.3894 0.9652 0.0000 0.9652Central Avg. 0.3894 0.6735 0.0000 0.6735East Avg. 0.3894 0.8501 0.0087 0.8588

The above estimates are then converted to MJ/m of joint tape (52 mm wide) assuming paper weightof 0.2358 kg/m2 (Table 5.7). [For example, for waste paper transportation: 0.3894 GJ/tonne(=MJ/kg) x 0.2358 kg/m2 = 0.09182 MJ/m2 of paper stock for joint tape; m2 of such paperprovides 19.23 lineal meters of paper tape 52 mm wide; 0.09182 MJ/m2 / 19.23 m = 0.477 MJ/mof tape.] Taking into consideration typical usage of 0.98 m of tape per m2 of gypsum board, unitfactors can be expressed also per m2 of the board (Table 5.8).

TABLE 5.7 AVERAGE ENERGY USE FOR JOINT PAPER TAPE RAW MATERIALS TRANSPORTATION (MJ/M OF JOINT TAPE)




TABLE 5.8 AVERAGE ENERGY USE FOR JOINT PAPER TAPE RAW MATERIALS TRANSPORTATION (MJ/M2 OF BOARD)





5.2 JOINT FINISHING PRODUCTS MANUFACTURING

Joint compounds manufacturing consists of a number of separate steps, namely through:

• industrial minerals processing,• resin binder production, and• joint compound compounding (processing).

Limestone, talc, mica and clays are subjected to secondary crushing, drying and grinding. Gypsumgoes through the same processing, followed by calcination and stucco (plaster) grinding. While wehad detailed information regarding energy inputs associated with the production of gypsum / plaster(Section 4.2, Table 4.6), similar detailed data for other industrial minerals used in joint compoundproduction is not readily available. We therefore assumed that energy embodied in secondarycrushing, drying and grinding of limestone, mica, talc and clays is the same as that of the weightedCanadian average for gypsum. As all of these industrial minerals are indeed handled and processedin a similar manner, we believe that any error introduced into our estimates by this assumption isnegligible.

One of the leading PVA resin suppliers to the ready mix joint compound producers provided thetotal energy associated with the manufacturing of the binder as 200 BTU/lb (0.464 MJ/kg) of resin,with a 20/80 split between electricity and natural gas use.2 Typical electrical power usage neededfor compounding / processing (mixing, pumping, resin heating) of the joint compounds wasprovided by the Canadian producers. Total energy consumption estimates for manufacturing ofready mix and setting (dry) joint compounds were developed and tabulated by both the processingstep and the type of energy used. For ease of use, these estimates are presented both in MJ per kgof compound and MJ per m2 of gypsum board. Tables 5.9 to 5.12 show the unit factors for theready mix compounds, Tables 5.13 to 5.16 do the same for the setting compounds.

TABLE 5.9 WEIGHTED AVERAGE ENERGY USE IN READY MIX JOINT COMPOUND MANUFACTURING BY PROCESS STEP (MJ/KG OF COMPOUND)

secondarycrushing

drying grinding totalminerals

processing

resinproduction

processing total

Water - - - - - - -Clay 0.00056 0.00600 0.00034 0.00690 - - 0.00690Talc 0.00126 0.01340 0.00076 0.01542 - - 0.01542Mica 0.00116 0.01235 0.00070 0.01420 - - 0.01420Calcium carbonate 0.01732 0.18449 0.01043 0.21224 - - 0.21224PVA resin - - - - 0.01855 - 0.01855Other 0.00003 0.00035 0.00002 0.00041 - - 0.00041Processing - - - - - 0.05400 0.05400

TOTAL 0 .02033 0 .21659 0 .01225 0 .24917 0 .01855 0 .05400 0 .32172


TABLE 5.10 WEIGHTED AVERAGE ENERGY USE IN READY MIX JOINT COMPOUND MANUFACTURING BY PROCESS STEP (MJ/M2 OF GYPSUM BOARD)

secondarycrushing

drying grinding totalminerals

processing

resinproduction

processing total

Water - - - - - - -Clay 0.00038 0.00404 0.00023 0.00465 - - 0.00465Talc 0.00085 0.00903 0.00051 0.01039 - - 0.01039Mica 0.00078 0.00832 0.00047 0.00957 - - 0.00957Calcium carbonate 0.01167 0.12435 0.00703 0.14305 - - 0.14305PVA resin - - - - 0.01250 - 0.01250Other 0.00002 0.00024 0.00001 0.00027 - - 0.00027Processing - - - - - 0.03640 0.03640

TOTAL 0 .01370 0 .14598 0 .00825 0 .16794 0 .01250 0 .03640 0 .21684

TABLE 5.11 WEIGHTED AVERAGE ENERGY USE IN READY MIX JOINT COMPOUND MANUFACTURING BY ENERGY FORM (MJ/KG OF COMPOUND)

natural gas oil diesel road electr ic total

Water - - - - -Clay 0.00340 0.00004 0.00249 0.00097 0.00690Talc 0.00760 0.00008 0.00557 0.00217 0.01542Mica 0.00700 0.00007 0.00513 0.00200 0.01420Calcium carbonate 0.10465 0.00108 0.07663 0.02988 0.21224PVA resin 0.00371 - - 0.01484 0.01855Other 0.00020 0.00000 0.00015 0.00006 0.00041Total raw mat. 0.12657 0.00127 0.08996 0.04992 0.26772Processing - - - 0.05400 0.05400

TOTAL 0 .12657 0 .00127 0 .08996 0 .10392 0 .32172


TABLE 5.12 WEIGHTED AVERAGE ENERGY USE IN READY MIX JOINT COMPOUND MANUFACTURING BY ENERGY FORM (MJ/M2 OF GYPSUM BOARD)


Water - - - - -Clay 0.00229 0.00002 0.00168 0.00065 0.00465Talc 0.00512 0.00005 0.00375 0.00146 0.01039Mica 0.00472 0.00005 0.00346 0.00135 0.00957Calcium carbonate 0.07054 0.00073 0.05165 0.02014 0.14305PVA resin 0.00250 - - 0.01000 0.01250Other 0.00013 0.00000 0.00010 0.00004 0.00027Total raw mat. 0.08531 0.00086 0.06063 0.03364 0.18044Processing - - - 0.03640 0.03640

TOTAL 0 .08531 0 .00086 0 .06063 0 .07004 0 .21684

TABLE 5.13 WEIGHTED AVERAGE ENERGY USE IN SETTING JOINT COMPOUND MANUFACTURING BY PROCESS STEP (MJ/KG OF COMPOUND)

secondarycrushing


processing total

Gypsum plaster 0.01935 0.20612 0.01166 0.50680 0.00297 - 0.74690Calcium carbonate 0.01209 0.12876 0.00728 - - - 0.14812Mica 0.00238 0.02540 0.00144 - - - 0.02922Clay 0.00166 0.01764 0.00100 - - - 0.02029Other 0.00093 0.00988 0.00056 - - - 0.01136Compounding - - - - - 0.04320 0.04320

TOTAL 0 .03640 0 .38779 0 .02193 0 .50680 0 .00297 0 .04320 0 .99909

TABLE 5.14 WEIGHTED AVERAGE ENERGY USE IN SETTING JOINT COMPOUND MANUFACTURING BY PROCESS STEP (MJ/M2 OF GYPSUM BOARD)

secondarycrushing


processing total

Gypsum plaster 0.00681 0.07256 0.00410 0.17839 0.00105 - 0.26291Calcium carbonate 0.00425 0.04532 0.00256 - - - 0.05214Mica 0.00084 0.00894 0.00051 - - - 0.01028Clay 0.00058 0.00621 0.00035 - - - 0.00714Other 0.00033 0.00348 0.00020 - - - 0.00400Compounding - - - - - 0.01521 0.01521

TOTAL 0 .01281 0 .13650 0 .00772 0 .17839 0 .00105 0 .01521 0 .35168


TABLE 5.15 WEIGHTED AVERAGE ENERGY USE IN SETTING JOINT COMPOUND MANUFACTURING BY ENERGY FORM (MJ/KG OF COMPOUND)


Gypsum plaster 0.45063 0.16370 0.08561 0.04694 0.74690Calcium carbonate 0.07304 0.00076 0.05348 0.02085 0.14812Mica 0.01441 0.00015 0.01055 0.00411 0.02922Clay 0.01000 0.00010 0.00733 0.00286 0.02029Other 0.00560 0.00006 0.00410 0.00160 0.01136Compounding - - - 0.04320 0.04320

TOTAL 0 .55368 0 .16477 0 .16107 0 .11956 0 .99909

TABLE 5.16 WEIGHTED AVERAGE ENERGY USE IN SETTING JOINT COMPOUND MANUFACTURING BY ENERGY FORM (MJ/M2 OF GYPSUM BOARD)


Gypsum plaster 0.15863 0.05763 0.03014 0.01653 0.26291Calcium carbonate 0.02571 0.00027 0.01882 0.00734 0.05214Mica 0.00507 0.00005 0.00371 0.00145 0.01028Clay 0.00352 0.00004 0.00258 0.00101 0.00714Other 0.00197 0.00002 0.00144 0.00056 0.00400Compounding - - - 0.01521 0.01521

TOTAL 0 .19490 0 .05800 0 .05670 0 .04209 0 .35168

Weighted average energy use in gypsum paper production was discussed in Section 4.2, and shownin Table 4.11. Due to the already noted similarity between the paper used for joint tape and thegypsum facings, we will assume that the embodied manufacturing energy for both types of paper isthe same. The only other energy input in the joint tape manufacturing is the power needed to lightlysand the paper and to slit the large paper rolls into the rolls of paper tape. In comparison with theother paper manufacturing energy inputs, this is negligible, and we will not consider it in our totals.

The energy estimates expressed per mass of paper in Table 4.11 are converted to MJ/m of joint tape(52 mm wide) assuming paper weight of 0.2358 kg/m2, and taking into consideration typical usageof 0.98 m of tape per m2 of gypsum board, unit factors are also expressed per m2 of the board(Table 5.17).


TABLE 5.17 WEIGHTED AVERAGE ENERGY USE IN MANUFACTURING OF JOINT PAPER TAPE BY ENERGY FORM


GJ/tonne of paper 11.60470 0.61080 2.91480 15 .13020MJ/m of tape 0.14229 0.00749 0.03574 0 .18552MJ/m2 of gypsum board 0.13945 0.00734 0.03503 0 .18181

5.3 JOINT FINISHING PRODUCTS TRANSPORTATION

This subsection provides information regarding the distances and modes of the transportation ofjoint finishing products from their point of manufacture to the distribution centres across Canada.The ATHENATM computer model uses these data to calculate the energy consumption associatedwith the finished products transportation from the plant gate to the market. Here, in the study, weshow some estimates just for illustration. Information regarding transportation distances andmodes obtained from some of the individual producers was supplemented by other knowngeographical market distribution data. Based on our knowledge of the Canadian gypsum board andassociated finishing products markets, we made some assumptions regarding the relative marketshare between the various national as well as regional producers.

Based on the information received from the joint compounds producers, we concluded that:

• Vancouver is served 70% by a local producer, 30% from Calgary, all by truck,• Calgary is served 50% by a local producer, 40% from Edmonton, both by truck,

and the remaining 10% from Ontario by rail,• Winnipeg is supplied 40% from Calgary, 60% from Ontario, both by rail, with

remaining local transport by truck,• Toronto is served 70% by Ontario producers, with the remaining 30% coming

from Montreal, all by truck,• Montreal is served 100% by local producers, all by truck,• Halifax is supplied 90% from plants in Montreal, shipped by rail and locally

distributed by truck, with the remaining 10% served by a smaller regional supplier.

Further, it was assumed that only 20% backhaul is involved in the local truck transport, 50%backhaul in the long distance (inter-city) truck transport, and 100% backhaul in the rail transport ofthe finished goods. The weighted average transportation distances by mode were then developedusing the distances of each production facilities from the designated cities, and are shown in Table5.18. For joint paper tape we assumed the same transportation distances and modes of transport asfor the joint compounds, as in most cases it is produced and shipped from the same productionfacility as the joint compounds.


TABLE 5.18 WEIGHTED AVERAGE TRANSPORTATION DISTANCES BY MODE FOR JOINT FINISHING PRODUCTS (KM)


Truck Rail

Vancouver 490.5 0Calgary 234 300Winnipeg 90 1740Toronto 372 0Montreal 90 0Halifax 126 1125

Transport factors [MJ/tonne-km] 1.18 0.49


The weighted average distances from table 5.18 were converted to the energy estimates by applyingthe appropriate energy per tonne-km consumption factors. The resulting estimates of the finishedproducts transportation energy unit factors are shown in Tables 5.20 to 5.24.

TABLE 5.20 WEIGHTED AVERAGE TRANSPORTATION ENERGY FOR FINISHED JOINT COMPOUNDS (MJ/KG OF COMPOUND)

Truckdiesel-road

Raildiesel-rail

Total

Vancouver 0.57879 0.00000 0.57879Calgary 0.27612 0.14700 0.42312Winnipeg 0.10620 0.85260 0.95880Toronto 0.43896 0.00000 0.43896Montreal 0.10620 0.00000 0.10620Halifax 0.14868 0.55125 0.69993

TABLE 5.21 WEIGHTED AVERAGE TRANSPORTATION ENERGY FOR FINISHED READY MIX JOINT COMPOUNDS (MJ/M2 OF BOARD)

Truckdiesel-road

Raildiesel-rail

Total



TABLE 5.22 WEIGHTED AVERAGE TRANSPORTATION ENERGY FOR FINISHED SETTING JOINT COMPOUNDS (MJ/M2 OF BOARD)

Truckdiesel-road

Raildiesel-rail

Total


TABLE 5.23 WEIGHTED AVERAGE TRANSPORTATION ENERGY FOR FINISHED JOINT PAPER TAPE (MJ/M OF TAPE)

Truckdiesel-road

Raildiesel-rail

Total


TABLE 5.24 WEIGHTED AVERAGE TRANSPORTATION ENERGY FOR FINISHED JOINT PAPER TAPE (MJ/M2 OF BOARD)

Truckdiesel-road

Raildiesel-rail

Total


5.4 JOINT FINISHING PRODUCTS - ENERGY SUMMARY

In this section we summarize all the preceding energy estimates associated with production of readymix joint compounds, setting joint compounds, and joint paper tape by processing stage and byenergy form. In the following tables (5.25 to 5.30), all these unit factors are expressed in both thecustomary units that the products are marketed in, i.e. in MJ per kg for joint compounds and in MJ


per lineal meter for tape, as well as per m2 of gypsum board, so that their usage (and associatedenergy) can be directly related to the gypsum board that it complements and finishes.

The relative distribution of energy used in production of associated finishing products by processstep is shown in Table 5.31 and Fig. 5.1. In a sharp contrast with gypsum board, where themanufacturing step represents the biggest share of the embodied energy, for joint compounds it isthe raw materials transportation that contributes most to the total energy consumption. Combinedraw materials and finished goods transportation represents almost 75% of the total energy use.

TABLE 5.31 AVERAGE DISTRIBUTION OF ENERGY USE IN JOINT FINISHING PRODUCTS PRODUCTION BY PROCESS STAGE [%]

Extraction Raw MaterialsTransport

Manufacturing FinishedGoods

Transport

ready mix joint compounds 1.25 40.50 24.27 33.98setting (dry) joint compounds 0.77 59.95 25.98 13.30joint paper tape - 7.24 89.62 3.14

Ready Mix Setting Compound Joint Tape0

20

40

60

80

100

Extraction

RM Transport

Manufacturing

Finished Transport

%

of

tota

l e

ne

rgy

u

se

Fig. 5.1: Breakdown of Energy Use in Joint Finishing Products Production by Process Stage


TABLE 5.25 ENERGY USE IN READY MIX JOINT COMPOUNDS PRODUCTION BY PROCESS STAGE AND REGION

Ex-traction

RawMaterialsTransport

Manufacturing Totalto

Gate

FinishedProductsTransport

Totalto

Market

mineralspro-

cessing

resinpro-

duction

pro-cessing

totalmanu-

facturing

[MJ/kg of compound]

Vancouver 0.01658 0.84773 0.24917 0.01855 0.05400 0.32172 1.18603 0.57879 1.76482Calgary 0.01658 0.84773 0.24917 0.01855 0.05400 0.32172 1.18603 0.42312 1.60915Winnipeg 0.01658 0.74805 0.24917 0.01855 0.05400 0.32172 1.08635 0.95880 2.04515Toronto 0.01658 0.74805 0.24917 0.01855 0.05400 0.32172 1.08635 0.43896 1.52531Montreal 0.01658 0.25816 0.24917 0.01855 0.05400 0.32172 0.59646 0.10620 0.70266Halifax 0.01658 0.25816 0.24917 0.01855 0.05400 0.32172 0.59646 0.69993 1.29639

[MJ/m2 of board]

Vancouver 0.01117 0.57137 0.16794 0.01250 0.03640 0.21684 0.79938 0.39010 1.18949Calgary 0.01117 0.57137 0.16794 0.01250 0.03640 0.21684 0.79938 0.28518 1.08457Winnipeg 0.01117 0.50418 0.16794 0.01250 0.03640 0.21684 0.73220 0.64623 1.37843Toronto 0.01117 0.50418 0.16794 0.01250 0.03640 0.21684 0.73220 0.29586 1.02806Montreal 0.01117 0.17400 0.16794 0.01250 0.03640 0.21684 0.40201 0.07158 0.47359Halifax 0.01117 0.17400 0.16794 0.01250 0.03640 0.21684 0.40201 0.47175 0.87377


TABLE 5.26A CRADLE TO GATE ENERGY USE IN READY MIX JOINT COMPOUNDS PRODUCTION BY ENERGY FORM AND REGION

diesel-road diesel-rail natural gas oil electr ic TOTAL

[MJ/kg of compound]

Vancouver 0.95427 0.00000 0.12657 0.00127 0.10392 1 .18603Calgary 0.95427 0.00000 0.12657 0.00127 0.10392 1 .18603Winnipeg 0.85459 0.00000 0.12657 0.00127 0.10392 1 .08635Toronto 0.85459 0.00000 0.12657 0.00127 0.10392 1 .08635Montreal 0.36470 0.00000 0.12657 0.00127 0.10392 0 .59646Halifax 0.36470 0.00000 0.12657 0.00127 0.10392 0 .59646

[MJ/m2 of board]


TABLE 5.26B CRADLE TO MARKET ENERGY USE IN READY MIX JOINT COMPOUNDS PRODUCTION BY ENERGY FORM AND REGION


[MJ/kg of compound]


[MJ/m2 of board]



TABLE 5.27 ENERGY USE IN SETTING JOINT COMPOUNDS PRODUCTION BY PROCESS STAGE AND REGION

Extraction RawMaterialsTransport

Manufacturing Totalto

Gate

FinishedProductsTransport

Totalto

Market

mineralspro-

cessing

pro-cessing

totalmanu-

facturing

[MJ/kg of compound]

Vancouver 0.02968 2.67120 0.95589 0.04320 0.99909 3 .69997 0.57879 4 .27876Calgary 0.02968 2.67120 0.95589 0.04320 0.99909 3 .69997 0.42312 4 .12309Winnipeg 0.02968 2.32218 0.95589 0.04320 0.99909 3 .35095 0.95880 4 .30975Toronto 0.02968 2.32218 0.95589 0.04320 0.99909 3 .35095 0.43896 3 .78991Montreal 0.02968 1.99514 0.95589 0.04320 0.99909 3 .02391 0.10620 3 .13011Halifax 0.02968 1.99514 0.95589 0.04320 0.99909 3 .02391 0.69993 3 .72384

[MJ/m2 of board]

Vancouver 0.01045 0.94026 0.33647 0.01521 0.35168 1 .30239 0.20373 1 .50612Calgary 0.01045 0.94026 0.33647 0.01521 0.35168 1 .30239 0.14894 1 .45133Winnipeg 0.01045 0.81741 0.33647 0.01521 0.35168 1 .17953 0.33750 1 .51703Toronto 0.01045 0.81741 0.33647 0.01521 0.35168 1 .17953 0.15451 1 .33405Montreal 0.01045 0.70229 0.33647 0.01521 0.35168 1 .06442 0.03738 1 .10180Halifax 0.01045 0.70229 0.33647 0.01521 0.35168 1 .06442 0.24638 1 .31079


TABLE 5.28A CRADLE TO GATE ENERGY USE IN SETTING JOINT COMPOUNDS PRODUCTION BY ENERGY FORM AND REGION


[MJ/kg of compound]


[MJ/m2 of board]


TABLE 5.28B CRADLE TO MARKET ENERGY USE IN SETTING JOINT COMPOUNDS PRODUCTION BY ENERGY FORM AND REGION


[MJ/kg of compound]


[MJ/m2 of board]



TABLE 5.29 ENERGY USE IN JOINT PAPER TAPE PRODUCTION BYPROCESS STAGE AND REGION

Raw Materials Transport Manu-facturing

Totalt o

G a t e

FinishedJointTape

Transport

Totalt o

Market

wastepaper

finishedpaper

total RMstransport

[MJ/kg]

Vancouver 0.38940 0.96520 1.35460 15.13020 16 .48480 0.57879 17 .06359Calgary 0.38940 0.96520 1.35460 15.13020 16 .48480 0.42312 16 .90792Winnipeg 0.38940 0.67350 1.06290 15.13020 16 .19310 0.95880 17 .15190Toronto 0.38940 0.67350 1.06290 15.13020 16 .19310 0.43896 16 .63206Montreal 0.38940 0.85880 1.24820 15.13020 16 .37840 0.10620 16 .48460Halifax 0.38940 0.85880 1.24820 15.13020 16 .37840 0.69993 17 .07833

[MJ/m of tape]


[MJ/m2 of board]



TABLE 5.30A CRADLE TO GATE ENERGY USE IN JOINT PAPER TAPE PRODUCTION BY ENERGY FORM AND REGION

diesel-road

diesel-rail

HFO-marine

naturalgas

oil electr ic TOTAL

[MJ/kg]

Vancouver 1.35460 0.00000 0.00000 11.60470 0.61080 2.91480 16 .48490Calgary 1.35460 0.00000 0.00000 11.60470 0.61080 2.91480 16 .48490Winnipeg 1.06290 0.00000 0.00000 11.60470 0.61080 2.91480 16 .19320Toronto 1.06290 0.00000 0.00000 11.60470 0.61080 2.91480 16 .19320Montreal 1.23950 0.00000 0.00870 11.60470 0.61080 2.91480 16 .37850Halifax 1.23950 0.00000 0.00870 11.60470 0.61080 2.91480 16 .37850

[MJ/m of tape]


[MJ/m2 of board]



TABLE 5.30B CRADLE TO MARKET ENERGY USE IN JOINT PAPER TAPE PRODUCTION BY ENERGY FORM AND REGION

diesel-road

diesel-rail

HFO-marine

naturalgas

oil electr ic TOTAL

[MJ/kg]


[MJ/m of tape]


[MJ/m2 of board]


REFERENCES

1. Canadian Industry Program for Energy Conservation (CIPEC), Ministry of Energy, Mines andResources Canada, 1989.

2. Confidential information from the leading PVA resin manufacturer, January 1996.


6.0 ATMOSPHERIC EMISSIONS - GYPSUM BOARD

This section addresses atmospheric emissions associated with the production of gypsum board inall its processing stages, from the extraction and transportation of raw materials throughmanufacturing and final transportation to markets.

Like any energy-burning production process, gypsum board production generates common airpollutants including carbon dioxide (CO2), sulfur oxides (SOx ) — primarily sulfur dioxide (SO2)— nitrogen oxides (NOx ), volatile organic compounds (VOC), methane (CH4), and carbonmonoxide (CO) as well as total particulate matter (TPM). These energy-related emissions aretermed “fuel emissions”.

In a major contrast between gypsum-based products and those based on limestone, there is noadditional CO2 released during the calcination of gypsum. In processing of limestone in thecement or lime industries, a substantial amount of CO2 (about 60% of the total) is released due toits dissociation (calcination) at high temperatures. Calcination of gypsum that occurs at much lowertemperatures releases only some of the molecular water. The relatively low gypsum calcinationtemperatures (at about 120° to 160°C as opposed to about 1,450°C for cement clinker processing)has another “positive” effect as far as the atmospheric emissions are concerned: no “thermal”NOx is generated. Therefore in a marked contrast to some other inorganic building materialsindustries, apart from the particulate emissions, fuel emissions are the only emissions generated inthe production of gypsum board.

As in the energy section of the report, all results are presented in terms of weighted averagesdeveloped for the three geographical regions (West, Central and East), and adjusted to take intoaccount transportation of the gypsum board to the six cities (Vancouver, Calgary, Winnipeg,Toronto, Montreal and Halifax), following the same assumptions regarding shipping distances andmodes of transportation, as shown and discussed in Section 4.3.

Essentially no data on measured atmospheric emissions is publicly available from the gypsumindustry. In developing our atmospheric emission estimates, therefore, energy consumption unitfactors developed in Section 4 were used as a base to calculate CO2, SO2, NOx, CO, CH4 and VOCreleases. Contributions to atmospheric emissions by both the gypsum board production processstages and source of energy/fuel are tabulated and discussed in some detail, including theassumptions made and the reasoning for them.

6.1 APPROACHWith the exception of those related to electricity, energy-related atmospheric emission estimateswere developed using the energy estimates by process stage from Section 4 and energy emissionfactors as given in Tables 3 and 6 of the Research Guidelines, based on factors developed byNatural Resources Canada’s “Ad Hoc Committee on Emission Factors”.1 Applicable energyemission factors used throughout this work are summarized in Table 6.1.


Emissions related to the generation of electricity used by the gypsum board industry are notincluded in the tables that follow in this section. These emissions are being calculated separatelywithin the Sustainable Materials Project calculation model for all of the products underconsideration (i.e. concrete, steel, wood, gypsum board, and other materials under development).The estimates of electricity use in gypsum board production presented in this report will betranslated into the mix of primary energy forms used to generate the electricity for the relevantregional electrical systems. Corresponding atmospheric emissions will then be added in the modelto the other emissions estimated in this study.

TABLE 6.1 ENERGY EMISSION FACTORS (KG/GJ)

CO2 SO2 NOx VOC CH4 C O

Natural gas 49.700 0.0002 0.0590 0.00120 0.00130 0.01500Diesel road 70.700 0.1020 0.8070 0.08690 0.02170 0.44300Diesel rail 70.700 0.1020 1.4000 0.07000 0.00780 0.05700H.F. oil marine 74.000 0.4500 0.2000 0.36000 0.04000 0.00740H.F. oil industrial. 74.000 0.8375 0.1600 0.00290 0.00082 0.01440Coal - Central 87.600 0.8360 0.2500 0.00150 0.00054 0.09300

6.2 ATMOSPHERIC EMISSION ESTIMATES6.2.1 Raw Materials ExtractionRaw materials extraction (usually quarrying in open pit operations) involves drilling and blasting,with fractured rock handled and loaded onto trucks using front-end loaders, mechanical shovels andtraxcavators. Most of this equipment uses diesel fuel, although some sites use electrical poweronly. Some heavy fuel oil and coal (for steam generation) are also used for on-site drying of boththe natural and by-product gypsum. Atmospheric emissions were estimated using the weightedaverage energy estimates for raw materials extraction and on-site processing (Section 4.1) togetherwith appropriate diesel-road, heavy fuel oil, and coal emission factors.

Drilling, blasting and loading operations also create dust emissions. Environment Canada’s reportentitled A Nationwide Inventory of Emissions of Air Contaminants 2 quotes particulate emissionfactors taken from a U.S. Environmental Protection Agency (EPA) paper.3 For open-pit mining, aparticulate emission factor of 0.51 kg/tonne is given, whereas for underground mining a factor of0.05 kg/tonne is shown. As in some areas gypsum from both underground mines and quarries isused, weighted average particulate emission factors per tonne of rock were developed for theCanadian gypsum industry. We also have to take into account that natural rock represents adifferent percentage of the total gypsum supply in various regions of the country. Based on thelimited amount of data from some gypsum quarries and mines, we assumed that on average 0.373tonnes of solid waste is generated per tonne of extracted gypsum. Applying this multiplier (1.373),as well as another for conversion of gypsum to stucco (1.2048), as discussed in Section 3.1, weobtain the following TPM factors:


TABLE 6.2 WEIGHTED AVERAGE TPM EXTRACTION FACTORS APPLICABLE TO CANADIAN GYPSUM INDUSTRY

Natural gypsum as% of total supply

TPM emissions(kg/tonne of rock)

TPM emissions(kg/tonne of stucco)

West 86.50 0.5100 0.7297Central 85.33 0.0970 0.1369East 81.26 0.3662 0.4922

(As an example: weighted average TPM factor for the East region = 0.3662 (weighted average of 0.05 for

underground mines and 0.51 for quarries, reflecting their relative contribution in the region) multiplied by 0.8126

(share of the natural gypsum in the total gypsum supply) times 1.373 (to account for mining solid waste) times

1.2048 (to convert to per tonnes of stucco units) =

TPM East = 0.3662 x 0.8126 x 1.373 x 1.2048 = 0.4922.)

For estimates of extraction TPM of gypsum fiberboard, we considered the fact that only locallyquarried natural gypsum is used in its production. The contribution of perlite quarrying to the totalparticulate emissions was also taken into account.

These factors were used to estimate weighted averages for total particulate (TPM) emissions due toraw materials extraction. It should be noted that the EPA extraction emissions factors also includeparticulate emissions due to raw materials transportation. However, as the transportation particulateemissions are rather small in comparison to the extraction dust emissions, we felt that using theEPA numbers results in only a small error in the allocation of particulate emissions and, what ismore important, both particulate emissions are still captured in the totals. Although blasting agentsalso generate some nitrogen oxides and some hydrocarbons, these emissions do not contributesignificantly to the pollution burden, and are considered to be negligible.1

Total estimated atmospheric emissions due to gypsum board raw materials extraction, for a 1/2"thick regular gypsum board, are shown in Table 6.3. The emissions for the other types of gypsumboards are tabulated in the summary part of this section.

TABLE 6.3 ATMOSPHERIC EMISSIONS DUE TO GYPSUM BOARD RAW MATERIALS EXTRACTION (G/M2 OF 1/2" REGULAR GYPSUM BOARD)

CO2 SO2 NOx VOC CH4 C O TPM



6.2.2 Raw Materials TransportationRaw materials transportation energy unit factors based on information provided directly by mostgypsum board manufacturing operations were shown in Section 4.1, Tables 4.4 and 4.6 for 1/2"regular gypsum board. These factors were multiplied by the appropriate emission factors fromTable 6.1. The resulting raw materials transportation emissions estimates for such a board arepresented in Table 6.4. As noted above, particulate emissions related to raw material transportationare included in Table 6.3. Again, the emissions for the other gypsum board products are shown inthe summary part of this section.

TABLE 6.4 ATMOSPHERIC EMISSIONS DUE TO GYPSUM BOARD RAW MATERIALS TRANSPORTATION (G/M2 OF 1/2" REGULAR GYPSUM BOARD)


West Avg. 753.17 2.0090 7.6994 1.6250 0.2581 2.9497Central Avg. 153.92 0.2221 1.7569 0.1892 0.0472 0.9644East Avg. 453.40 1.0769 4.3813 0.8887 0.1605 2.2790CANADA 371.37 0.8615 3.8322 0.7059 0.1256 1.7605

6.2.3 Gypsum Board Manufacturing

Atmospheric emissions are generated in all steps of the gypsum board manufacturing processdescribed in Section 2 of this report, i.e. in gypsum calcination, in the paper making process, and inthe gypsum board manufacturing itself. Use of energy to drive the crushers, screens, hammer mills,Raymond mills, the various conveyors, and especially fuel combustion in the calcination step,generates all the common air pollutants (i.e. CO2, SO2, NOx, VOCs, CH4 and CO) usuallyassociated with energy consumption. Similarly the paper manufacturing process energy use in allthe processing steps, from waste paper defiberization through paper formation, pressing, drying andcalendering, generates atmospheric fuel emissions.

Of the three board processing steps, the gypsum board manufacturing, due to the board drying inheated board kilns, uses about the same amount of energy as the other two steps combined (Table4.35). Fossil fuels providing the kiln heat produce the common atmospheric emissions.

Particulate matter is also generated as rock gypsum is dried and reduced to fine particles throughcrushing and milling, and as gypsum is conveyed and processed in the calcination kettles to stucco,and eventually into the board. A nationwide emissions inventory (1978)2 offers uncontrolledparticulate emission factors (Table 6.5) based on the U.S. EPA 1977 data, and in calculation of theactual TPM emissions it assumes 90% control efficiency. Considering the advances in theparticulate emissions controls and their implementation, these data appear to be somewhat obsoletenow. Particulate emissions from paper board production are considered to be negligible.2


As any industry, the gypsum industry has been under some pressure to control its particulateemissions. High efficiency baghouses and some electrostatic precipitators are installed and used inall modern gypsum operations, and this is reflected in updated U.S. EPA 1983 controlledparticulate emission factors.4 The EPA controlled emissions indicate 99.7% control efficiency. Atthe same time, however, the large spread in the factor estimates is an indication that there is relativelylittle actual measured data available, mainly due to the fact that the gypsum industry does notpresent any substantial particulates problem. This is best summarized in a response from one ofthe provincial authorities: “Based on site inspections, which demonstrated no visible particulateemissions, the Company was not required to do particulate stack testing.”

Estimates of particulate emissions were obtained from provincial environmental ministries inQuebec, Ontario and from GVRD (Greater Vancouver Regional District). Ontario data cover allproducers, and as such appear to be representative of the situation in the province. The reportedweighted average TPM emissions of 0.2109 g/m2 are substantially better than even EPA assumedcontrolled emission. This is not surprising, considering that the Ontario plants are the flagshipoperations of the respective producers, and as such their emissions controls will be close to thestate-of-the-art. As Ontario represents close to 90% of the Central region, we will use this factorfor the entire region. For the East we received data concerning only one plant. At 0.7546 g/m2 ofboard, it is close to the EPA estimate, and we will assume that it is representative of the wholeregion. The GVRD data are permit data giving the maximum allowable annual emissions, butproviding only scant measured data. From this limited actual emission monitoring, it would appearthat the performance at 1.7494 g/m2 is substantially better than maximum potential assessment,although not as good as in the other regions. The above discussed gypsum board manufacturingTPM factors are summarized in Table 6.6.

TABLE 6.5 ENVIRONMENT CANADA AND U.S. EPA PARTICULATE EMISSION FACTORS FOR GYPSUM PROCESSING (KG/TONNE)

Environment Canada 1978Inventory2

U.S. EPA AP-42 19854

uncontrolledemissions

controlledemissions*

uncontrolledemissions

controlledemissions**

raw material drying 20.0 2.0 5 – 60 0.02primary grinding 0.5 0.05 1.3 0.06calcining 45.0 4.5 21 0.003conveying 0.35 0.035 - -board sawing - - 0.005 -TOTAL 65.85 6.585 27.305 – 82.305 0.083

TOTAL g/m2 for 1/2"board; gypsum use7.6637 kg/m2 of board

504.66 50.47 209.26 – 630.76 0.636

notes: * assuming 90% control efficiencies, ** with baghouse / fabric filter


TABLE 6.6 ESTIMATES OF PARTICULATE EMISSION FACTORS FOR GYPSUM PROCESSING BY REGION (G/M2 OF 1/2" BOARD)

Weighted TPM Emissions

West Region 1.7494Central Region 0.2109East Region 0.7546

Processing (expansion) of perlite used in manufacturing of gypsum fiberboard also generatesparticulate emissions. According to U.S. EPA, uncontrolled emissions for perlite expansion are10.5 kg/tonne.5 For our estimates, we will use the same particulate emissions as for gypsum(assuming that perlite expansion generates about the same TPM as gypsum calcination) in the Eastregion adjusted for relative usage of gypsum and perlite in GFB.

Weighted averages of estimates for atmospheric emissions due to all three manufacturing stages ofgypsum board production, as well as the total, are summarized in Tables 6.7 to 6.10 for 1/2" regulargypsum board. The emissions for the other board products are shown in the summary part of thissection.

TABLE 6.7 ATMOSPHERIC EMISSIONS DUE TO STUCCO CALCINATION(G/M2 OF 1/2” REGULAR GYPSUM BOARD)


West 642.37 2.4903 0.9770 0.0188 0.0135 0.1703 1.7494Central 435.98 1.1865 1.4019 0.1052 0.0317 0.5832 0.2109East 668.64 3.0635 2.8025 0.2280 0.0622 1.2052 0.7546CANADA 541.27 1.9472 1.6262 0.1128 0.0344 0.6277 0.7163

TABLE 6.8 ATMOSPHERIC EMISSIONS DUE TO GYPSUM PAPER PRODUCTION (G/M2 OF 1/2” REGULAR GYPSUM BOARD)


West 293.27 0.2423 0.3689 0.0074 0.0073 0.0862Central 293.27 0.2423 0.3689 0.0074 0.0073 0.0862East 293.27 0.2423 0.3689 0.0074 0.0073 0.0862CANADA 293.27 0.2423 0.3689 0.0074 0.0073 0.0862


TABLE 6.9 ATMOSPHERIC EMISSIONS DUE TO BOARD MANUFACTURING (G/M2 OF 1/2” REGULAR GYPSUM BOARD)



TABLE 6.10 SUBTOTAL OF ATMOSPHERIC EMISSIONS FROM ALL THREE MANUFACTURING STEPS (G/M2 OF 1/2” REGULAR GYPSUM BOARD)



Permissible levels of SO2, NOx and TPM emissions are regulated by the provinces. However, asgypsum board plants, in comparison with many other operations, generate relatively low emissions,there are no known monitoring data of such operations for either SO2 and NOx. According toindustry sources, monitoring of air quality with respect to TPM near board plants indicates that thecurrent emission limits are not exceeded.

6.2.4 Finished Gypsum Board Transportation

The ATHENATM computer model calculates atmospheric emissions associated with the finishedproducts transportation from the plant gate to the market, taking into consideration distances andtransport modes, as tabulated in Table 4.15. To better recall this information, it is shown in thissubsection again.

To provide a picture of atmospheric emissions associated with finished products transportation inthis study as well, the weighted average emissions related to finished 1/2" gypsum boardtransportation to market distribution centres were calculated by combining transportation energyemission factors from Table 6.1 with the estimates of transportation energy use by fuel typedeveloped and presented in Table 4.17. The results are shown in Table 6.11, while the finishedboard transportation emissions for the other gypsum board products are tabulated in the summarypart of this section.


TABLE 4.15 WEIGHTED AVERAGE TRANSPORTATION DISTANCES BY MODE FOR FINISHED GYPSUM BOARD (KM)


Truck Rail Ship

Vancouver 90 0 0Calgary 225 300 0Winnipeg 90 400 0Toronto 153 0 0Montreal 288 0 0Halifax 279 847.5 110

Transport factors [MJ/tonne-km] 1.18 0.49 0.12


TABLE 6.11 ATMOSPHERIC EMISSIONS DUE TO TRANSPORTATION OF FINISHED GYPSUM BOARD (G/M2 OF 1/2" REGULAR GYPSUM BOARD)


West Vancouver 60.54 0.0873 0.6910 0.0744 0.0186 0.3793Calgary 235.15 0.3393 3.3870 0.2690 0.0557 1.0159

Central Winnipeg 172.28 0.2485 2.9036 0.1850 0.0309 0.4694Toronto 102.92 0.1485 1.1748 0.1265 0.0316 0.6449

East Montreal 193.73 0.2795 2.2113 0.2381 0.0595 1.2139Halifax 432.29 0.6602 6.8514 0.5034 0.0880 1.3676


6.3 ATMOSPHERIC EMISSIONS SUMMARY

Total atmospheric emissions due to the production of 1/2" regular gypsum board are shown inTable 6.12. Comprehensive tables of atmospheric emissions by process stage for all gypsum boardproducts under consideration are shown as Tables 6.13 to 6.20.

TABLE 6.12 TOTAL ATMOSPHERIC EMISSIONS DUE TO GYPSUM BOARD PRODUCTION - FROM CRADLE TO MARKET

(G/M2 OF 1/2" REGULAR GYPSUM BOARD)


West Vancouver 2775.30 8.0786 11.3696 1.7708 0.3238 3.9446 6.3913Calgary 2949.91 8.3305 14.0655 1.9654 0.3609 4.5812 6.3913

Central Winnipeg 1968.06 4.0969 7.7294 0.5146 0.1388 2.3739 1.0818Toronto 1898.70 3.9968 6.0006 0.4560 0.1395 2.5494 1.0818

East Montreal 2716.01 11.0056 11.7598 1.4135 0.3138 5.1384 3.8858Halifax 2954.57 11.3863 16.3998 1.6787 0.3423 5.2921 3.8858


TABLE 6.13 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF1/2" REGULAR GYPSUM BOARD (G/M2)


Gypsum extraction & processing emissions


Total raw materials transportation emissions


Total manufacturing emissions


Cradle to gate emissions

West 2 7 1 4 . 7 6 7 . 9 9 1 3 1 0 . 6 7 8 5 1 . 6 9 6 4 0 . 3 0 5 2 3 . 5 6 5 3 6 . 3 9 1 3Central 1 7 9 5 . 7 8 3 . 8 4 8 3 4 . 8 2 5 8 0 . 3 2 9 5 0 . 1 0 7 9 1 . 9 0 4 5 1 . 0 8 1 8E a s t 2 5 2 2 . 2 8 1 0 . 7 2 6 1 9 . 5 4 8 5 1 . 1 7 5 3 0 . 2 5 4 3 3 . 9 2 4 5 3 . 8 8 5 8CANADA 2 1 9 2 . 5 3 6 . 4 8 2 1 7 . 3 7 6 7 0 . 8 6 4 3 0 . 1 9 0 9 2 . 7 8 9 1 3 . 0 4 3 8

Transportation emissions for the finished product




Total emissions associated with 1/2" regular board





TABLE 6.14 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF1/2" TYPE X FIRE RESISTANT GYPSUM BOARD (G/M2)









West 2 7 2 8 . 4 5 8 . 0 7 1 7 1 0 . 8 1 2 4 1 . 7 2 7 3 0 . 3 0 9 7 3 . 6 0 9 0 6 . 3 6 3 1Central 1 7 9 3 . 3 1 3 . 8 6 5 0 4 . 8 5 2 7 0 . 3 3 2 9 0 . 1 0 8 6 1 . 9 2 0 4 1 . 0 7 7 1E a s t 2 5 3 0 . 9 9 1 0 . 8 0 0 6 9 . 6 5 9 6 1 . 1 9 5 9 0 . 2 5 8 0 3 . 9 8 0 9 3 . 8 6 8 6CANADA 2 1 9 6 . 6 6 6 . 5 2 8 0 7 . 4 4 9 7 0 . 8 7 8 4 0 . 1 9 3 2 2 . 8 2 1 4 3 . 0 3 0 3





Total emissions associated with 1/2" type X board





TABLE 6.15 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF1/2" MR MOISTURE RESISTANT GYPSUM BOARD (G/M2)









West 2 9 0 7 . 3 3 8 . 5 9 8 6 1 1 . 8 1 6 8 1 . 9 1 3 6 0 . 3 4 0 9 3 . 9 6 5 7 7 . 0 0 8 7Central 1 8 8 0 . 5 5 4 . 0 4 3 3 5 . 2 2 5 9 0 . 3 6 5 5 0 . 1 1 7 8 2 . 0 9 5 6 1 . 1 8 6 3E a s t 2679 .64 11 .2910 10 .5010 1 . 3 2 3 0 0 . 2 8 3 8 4 . 3 8 2 0 4 . 2 6 1 1CANADA 2 3 2 0 . 8 9 6 . 8 6 5 5 8 . 0 8 8 4 0 . 9 7 1 0 0 . 2 1 1 7 3 . 0 9 4 5 3 . 3 3 7 8





Total emissions associated with 1/2" MR board





TABLE 6.16 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF5/8" REGULAR GYPSUM BOARD (G/M2)









West 3388 .64 10 .1655 13 .5918 2 . 1 9 4 5 0 . 3 9 0 8 4 . 5 2 5 2 8 . 3 4 5 3Central 2 1 9 8 . 9 4 4 . 8 1 9 9 6 . 0 1 4 5 0 . 4 1 5 1 0 . 1 3 4 7 2 . 3 8 7 9 1 . 4 1 2 6E a s t 3136 .16 13 .5700 12 .1348 1 . 5 1 7 2 0 . 3 2 5 5 5 . 0 1 6 7 5 . 0 7 3 7CANADA 2 7 1 1 . 8 0 8 . 1 8 9 1 9 . 3 1 8 5 1 . 1 1 1 4 0 . 2 4 2 5 3 . 5 3 3 2 3 . 9 7 4 3





Total emissions associated with 5/8" regular board





TABLE 6.17 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF5/8" TYPE X FIRE RESISTANT GYPSUM BOARD (G/M2)









West 3405 .02 10 .2404 13 .7216 2 . 2 2 2 6 0 . 3 9 5 1 4 . 5 6 8 8 8 . 4 6 4 0Central 2 2 0 0 . 8 4 4 . 8 3 8 3 6 . 0 4 7 6 0 . 4 1 8 6 0 . 1 3 5 5 2 . 4 0 5 7 1 . 4 3 2 7E a s t 3147 .99 13 .6395 12 .2429 1 . 5 3 6 1 0 . 3 2 9 0 5 . 0 7 0 5 5 . 1 4 5 9CANADA 2 7 1 9 . 6 0 8 . 2 3 3 4 9 . 3 9 3 0 1 . 1 2 4 6 0 . 2 4 4 8 3 . 5 6 5 8 4 . 0 3 0 9





Total emissions associated with 5/8" type X board





TABLE 6.18 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF5/8" MR MOISTURE RESISTANT GYPSUM BOARD (G/M2)









West 3611 .83 10 .8448 14 .8761 2 . 4 3 6 0 0 . 4 3 0 9 4 . 9 7 9 2 8 . 9 8 6 4Central 2 3 0 2 . 7 9 5 . 0 4 4 0 6 . 4 7 9 2 0 . 4 5 6 2 0 . 1 4 6 1 2 . 6 0 7 9 1 . 5 2 1 1E a s t 3320 .17 14 .2020 13 .2101 1 . 6 8 1 7 0 . 3 5 8 6 5 . 5 3 1 1 5 . 4 6 3 5CANADA 2 8 6 3 . 8 5 8 . 6 2 1 1 1 0 . 1 2 8 6 1 . 2 3 0 8 0 . 2 6 6 1 3 . 8 8 0 2 4 . 2 7 9 7





Total emissions associated with 5/8" MR board





TABLE 6.19 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF5/16" MOBILE HOME GYPSUM BOARD (G/M2)









West 1 9 4 8 . 4 5 5 . 4 8 5 6 7 . 7 3 1 9 1 . 2 1 8 6 0 . 2 2 1 2 2 . 6 2 7 4 4 . 4 8 7 8Central 1 3 0 2 . 2 4 2 . 6 3 7 3 3 . 5 5 1 4 0 . 2 4 6 5 0 . 0 8 0 3 1 . 4 2 1 0 0 . 7 5 9 6E a s t 1 8 0 2 . 3 1 7 . 1 6 3 2 6 . 8 6 0 3 0 . 8 4 5 7 0 . 1 8 4 3 2 . 8 5 7 2 2 . 7 2 8 5CANADA 1 5 7 8 . 6 9 4 . 4 0 0 5 5 . 3 5 8 3 0 . 6 2 6 3 0 . 1 3 9 4 2 . 0 5 6 2 2 . 1 3 7 3





Total emissions associated with 5/16" mobile home board





TABLE 6.20 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF1" SHAFTLINER GYPSUM BOARD (G/M2)









West 5715 .41 17 .6967 24 .2009 4 . 0 5 2 0 0 . 7 0 6 7 8 . 0 5 8 6 1 5 . 7 4 1 7Central 3 5 3 2 . 1 3 8 . 0 4 7 0 1 0 . 2 1 2 7 0 . 7 2 9 6 0 . 2 3 0 6 4 . 1 4 4 0 2 . 6 6 4 5E a s t 5223 .99 23 .0393 21 .4569 2 . 7 8 9 3 0 . 5 8 7 7 9 . 0 4 7 6 9 . 5 7 0 6CANADA 4466 .75 13 .9407 16 .2996 2 . 0 3 0 3 0 . 4 3 1 6 6 . 2 6 2 7 7 . 4 9 6 8





Total emissions associated with 1" shaftliner board





TABLE 6.21 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF1/2" GYPSUM FIBERBOARD (GFB) (G/M2)



17.91 0.0258 0.2045 0.0220 0.0055 0.1122 6.1276


229.97 1.069 1.409 0.856 0.104 0.352


2141.39 3.376 4.752 0.285 0.105 1.750 0.9697


2 3 8 9 . 2 8 4 . 4 7 0 5 6 . 3 6 5 0 1 . 1 6 2 3 0 . 2 1 4 5 2 . 2 1 4 6 7 . 0 9 7 3


Vancouver 2264.06 3.266 44.833 2.242 0.250 1.825Calgary 1891.11 2.728 37.448 1.872 0.209 1.525

Winnipeg 1371.62 1.979 27.161 1.358 0.151 1.106Toronto 704.03 1.016 13.941 0.697 0.078 0.568Montreal 494.68 0.714 9.796 0.490 0.055 0.399Halifax 336.10 0.485 3.836 0.413 0.103 2.106

Total emissions associated with 1/2" GFB





TABLE 6.22 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF5/8" GYPSUM FIBERBOARD (GFB) (G/M2)



22.23 0.0321 0.2537 0.0273 0.0068 0.1393 7.6031


285.35 1.326 1.748 1.062 0.129 0.437


2665.02 4.189 5.906 0.354 0.131 2.174 1.2031


2 9 7 2 . 6 0 5 . 5 4 7 0 7 . 9 0 7 2 1 . 4 4 2 4 0 . 2 6 6 4 2 . 7 5 0 3 8 . 8 0 6 2





Total emissions associated with 5/8" GFB





REFERENCES

1. “Emission Factors for Greenhouse and Other Gases by Fuel Type: An Inventory”, Energy,Mines and Resources Canada, Ad Hoc Committee on Emissions Factors, December 1990.

2. “A Nationwide Inventory of Emissions of Air Contaminants”, Environment Canada, ReportEPS 3-EP-83-10, December 1983.

3. “Metals Mining and Milling Process Profiles with Environmental Aspects, U.S.Environmental Protection Agency, EPA-600/2-76-167, Washington, USA, 1976.

4. “Compilation of Air Pollutant Emission Factors”, Section 8.14 “Gypsum Manufacturing”(May 1983), U.S. Environmental Protection Agency, EPA AP-42, 4th edition, September 1985.

5. “Compilation of Air Pollutant Emission Factors”, Section 8.17 “Gypsum Manufacturing”(February 1972), U.S. Environmental Protection Agency, EPA AP-42, 4th edition, September1985.


7.0 ATMOSPHERIC EMISSIONS - JOINT FINISHING PRODUCTS

In this section atmospheric emission estimates for joint finishing products are developed using thesame approach employed in the development of estimates for emissions associated with gypsumboard production, as was described in some detail in Section 6.0.

To calculate CO2, SO2, NOx, CO, CH4 and VOC releases, energy consumption unit factorsdeveloped in Section 5 were used as a base, combined with the energy emission factors as given inTables 3 and 6 of the Research Guidelines, based on factors developed by Natural ResourcesCanada’s “Ad Hoc Committee on Emission Factors”.1 Applicable energy emission factors usedthroughout this work were summarized in Section 6, Table 6.1. Contributions to atmosphericemissions, with the exception of those related to electricity, were developed for all three types offinishing products under consideration (ready mix joint compound, setting (dry) compound, andjoint paper tape). They are tabulated and discussed in the individual subsections below.

The emissions related to the generation of electricity are being calculated separately within theSustainable Materials Project calculation model for all of the products under consideration (i.e.concrete, steel, wood, gypsum board, and other materials under development). The estimates ofelectricity use in gypsum board and associated finishing products production presented in thisreport will be translated into the mix of primary energy forms used to generate the electricity for therelevant regional electrical systems. Corresponding atmospheric emissions will then be added inthe model to the other emissions estimated in this study.

7.1 ATMOSPHERIC EMISSION ESTIMATES

7.1.1 Raw Materials Extraction

As noted in Section 5.1, while both types of joint compounds are comprised of a number ofdifferent raw materials, all of those with embodied extraction energy are industrial minerals quarriedin open pits. Quarrying involves drilling and blasting, with fractured rock handled and loaded ontotrucks using front-end loaders, mechanical shovels and traxcavators. In agreement with theSustainable Materials Project Research Guidelines, we assumed that it takes 0.027 GJ/tonne2 forextraction of all of these materials, including gypsum, and that all this energy is in the form of dieselfuel - road. (As far as gypsum is concerned, this assumption is slightly different from thosediscussed for gypsum extraction for gypsum board production. However, as indicated in Section 5,gypsum used in production of setting compound is often calcined in a different manner, and it isalways natural gypsum of as high a purity as possible.) Furthermore we assumed that the sameamount of energy is required to extract the required quantities of raw materials in all geographicalregions, and that consequently the same emissions are generated all across Canada. Atmosphericemissions were estimated using the average energy estimates for joint compounds raw materialsextraction (Table 5.1) together with appropriate diesel-road emission factors from Table 6.1.


For the estimates of particulate emissions due to the drilling, blasting and loading in open-pitmining operations, a factor of 0.51 kg/tonne is used.3,4 For gypsum, we have assumed a highgrade quality gypsum deposit, and considered the requirement of 1.2048 tonnes of gypsum for atonne of stucco.

Resulting estimates of atmospheric emissions due to the extraction of raw materials for theproduction of ready mix joint compound are presented in Table 7.1, and those for setting jointcompounds in Table 7.2. As the joint paper tape is made entirely from recycled paper, we assumeno raw materials extraction or emissions there.

7.1.2 Raw Materials Transportation

In estimating raw materials transportation emissions factors, average raw materials energytransportation estimates (by energy form) developed in Section 5.1 (Tables 5.2 and 5.3 for readymix compound, 5.4 and 5.5 for setting compound, and 5.6-5.8 for joint paper tape) were multipliedby appropriate emission energy factors from Table 6.1. The resulting atmospheric emissionsestimates are shown in Tables 7.3 - 7.5. As already noted in Section 5, the specific grades ofindustrial minerals needed to produce joint compounds often have to be brought over from distantlocations. Consequently the raw materials transportation contribution to the total energy, andtherefore also to the atmospheric emissions total is rather high.

TABLE 7.1 ATMOSPHERIC EMISSIONS DUE TO READY MIX JOINT COMPOUND RAWMATERIALS EXTRACTION

CO2 S O 2 NOx VOC CH4 C O TPM

g/kg of compound

Vancouver 1.17206 0.00169 0.01338 0.00144 0.00036 0.00734 0.31314Calgary 1.17206 0.00169 0.01338 0.00144 0.00036 0.00734 0.31314Winnipeg 1.17206 0.00169 0.01338 0.00144 0.00036 0.00734 0.31314Toronto 1.17206 0.00169 0.01338 0.00144 0.00036 0.00734 0.31314Montreal 1.17206 0.00169 0.01338 0.00144 0.00036 0.00734 0.31314Halifax 1.17206 0.00169 0.01338 0.00144 0.00036 0.00734 0.31314

g/m2 of board



TABLE 7.2 ATMOSPHERIC EMISSIONS DUE TO SETTING JOINT COMPOUND RAW MATERIALS EXTRACTION


g/kg of compound


g/m2 of board


TABLE 7.3 ATMOSPHERIC EMISSIONS DUE TO READY MIX JOINT COMPOUND RAWMATERIALS TRANSPORTATION

CO2 S O 2 NOx VOC CH4 C O

g/kg of compound

Vancouver 59.93437 0.08647 0.68412 0.07367 0.01840 0.37554Calgary 59.93437 0.08647 0.68412 0.07367 0.01840 0.37554Winnipeg 52.88699 0.07630 0.60367 0.06501 0.01623 0.33139Toronto 52.88699 0.07630 0.60367 0.06501 0.01623 0.33139Montreal 18.25191 0.02633 0.20834 0.02243 0.00560 0.11436Halifax 18.25191 0.02633 0.20834 0.02243 0.00560 0.11436

g/m2 of board



TABLE 7.4 ATMOSPHERIC EMISSIONS DUE TO SETTING JOINT COMPOUND RAW MATERIALS TRANSPORTATION


g/kg of compound


g/m2 of board


TABLE 7.5 ATMOSPHERIC EMISSIONS DUE TO JOINT PAPER TAPE RAW MATERIALS TRANSPORTATION


kg/tonne of paper


g/meter of tape


g/m2 of board



7.1.3 Joint Finishing Products Manufacturing

Atmospheric emissions are generated in all steps of the finishing products manufacturing processwhere energy is used. Industrial raw minerals have to be processed - dried and reduced to propersize through secondary grinding and milling. Furthermore, gypsum used in the setting compoundshas to be calcined. The processing of joint compounds involves compounding and mixing of all theraw materials together, pumping and packaging of the finished materials. Use of energy in all theseprocessing steps results in generation of common air pollutants, although as most of the processingis done at room temperatures, in comparison with many other processes, the energy used and theresulting emissions are relatively low.

Particulate emissions are released in handling and processing of industrial minerals used in jointcompound production. We assumed that drying and secondary processing (grinding, milling) ofall industrial minerals will generate similar TPM emissions. Gypsum plaster processing, of course,includes the calcining caused TPM emission as well. Based on Environment Canada nationwideemission inventory (1978)3 data for gypsum processing (Table 5.5), we arrived at the followingcontrolled emission factors:

• limestone, mica, talc, clay 2.085 kg/tonne• gypsum plaster 6.585 kg/tonne

In Section 6 while discussing gypsum paper processing, in agreement with the EC nationwideemission inventory (1978) we assumed that the particulate emissions associated with paperproduction are negligible. Despite all the similarities between the gypsum paper and paper used forjoint tape production, however, we believe that in the case of joint tape some particulate emissionsare generated due to the sanding, buffing and cutting operations, that have to be taken intoconsideration. Based on U.S. EPA AP-425, the following particulate emission factors for papertape manufacturing was used:

• paper tape 0.3 kg/tonne.

The resulting estimates of atmospheric emissions associated with manufacturing of the threerelevant joint finishing materials are shown in Tables 7.6, 7.7 and 7.8. As we assumed the sameenergy inputs (Section 5.2) into these products’ manufacture in all production facilities acrossCanada, atmospheric emissions assigned to the manufacturing are the same in all six cities underconsideration.


TABLE 7.6 ATMOSPHERIC EMISSIONS DUE TO MANUFACTURING OF READY MIX JOINT COMPOUND AND ITS CONSTITUENTS


g/kg of compound


g/m2 of board


TABLE 7.7 ATMOSPHERIC EMISSIONS DUE TO MANUFACTURING OF SETTING JOINT COMPOUND AND ITS CONSTITUENTS


g/kg of compound


g/m2 of board



TABLE 7.8 ATMOSPHERIC EMISSIONS DUE TO MANUFACTURING OF PAPER JOINT TAPE


[kg/tonne of paper]


[g/meter of tape]


[g/m2 of board]


7.1.4 Finished Associated Products Transportation

The ATHENATM computer model calculates the finished products transportation emissions from thedistances and modes of transport, as shown in Table 5.18. For an illustration, some finishedassociated products transportation emissions are shown in this study as well. The averageatmospheric emissions due to transportation of finished associated products to the markets werecalculated by combining energy emission factors from Table 6.1 with the estimates of finishedproducts transportation energy use by fuel type developed and shown in Tables 5.20 to 5.24. Theresults are shown in Tables 7.9 for ready mix compound, 7.10 for setting compound, and 7.11 forjoint paper tape.


TABLE 7.9 ATMOSPHERIC EMISSIONS DUE TO TRANSPORTATION OF FINISHED READY MIX JOINT COMPOUND


g/kg of compound


g/m2 of board


TABLE 7.10 ATMOSPHERIC EMISSIONS DUE TO TRANSPORTATION OF FINISHED SETTING JOINT COMPOUND


g/kg of compound


g/m2 of board



TABLE 7.11 ATMOSPHERIC EMISSIONS DUE TO TRANSPORTATION OF FINISHED PAPER JOINT TAPE


[kg/tonne of paper]


[g/meter of tape]


[g/m2 of board]


7.2 JOINT FINISHING PRODUCTS ATMOSPHERIC EMISSIONS - SUMMARY

Total atmospheric emissions due to the production of ready mix joint compounds, setting jointcompounds, and joint paper tape, are summarized and shown in Tables 7.12, 7.13 and 7.14,respectively. The emission unit factors are expressed in both grams per unit of production and ingrams per m2 of gypsum board. More detailed summary tables showing breakdown due to processstage and region are shown in Tables 7.15 to 7.21.


TABLE 7.12 TOTAL ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF READY MIX JOINT COMPOUND


g/kg of compound


g/m2 of board


TABLE 7.13 TOTAL ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF SETTING JOINT COMPOUND


g/kg of compound


g/m2 of board



TABLE 7.14 TOTAL ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF PAPER JOINT TAPE


[kg/tonne of paper]


[g/meter of tape]


[MJ/m2 of board]



TABLE 7.15 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF READY MIX JOINTCOMPOUND BY PROCESS STAGE AND REGION (G/KG OF COMPOUND)


Extraction


Raw Materials Transport


Manufacturing


Cradle to Gate Emissions


Finished Products Transport


TOTAL



TABLE 7.16 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF READY MIX JOINTCOMPOUND BY PROCESS STAGE AND REGION (G/M2 OF BOARD)


Extraction




Manufacturing






TOTAL



TABLE 7.17 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF SETTING JOINT COMPOUND BY PROCESS STAGE AND REGION (G/KG OF COMPOUND)


Extraction




Manufacturing






TOTAL



TABLE 7.18 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF SETTING JOINT COMPOUND BY PROCESS STAGE AND REGION (G/M2 OF BOARD)


Extraction




Manufacturing






TOTAL



TABLE 7.19 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF JOINT PAPER TAPE BY PROCESS STAGE AND REGION (KG/TONNE OF PAPER)




Manufacturing




Finished Materials Transport


TOTAL



TABLE 7.20 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF JOINT PAPER TAPE BY PROCESS STAGE AND REGION (G/METER OF TAPE)




Manufacturing






TOTAL



TABLE 7.21 ATMOSPHERIC EMISSIONS DUE TO PRODUCTION OF JOINT PAPER TAPE BY PROCESS STAGE AND REGION (G/M2 OF BOARD)




Manufacturing






TOTAL



REFERENCES

1. “Emission Factors for Greenhouse and Other Gases by Fuel Type: An Inventory”, Energy,Mines and Resources Canada, Ad Hoc Committee on Emissions Factors, December 1990.

2. Canadian Industry Program for Energy Conservation (CIPEC), Ministry of Energy, Mines andResources Canada, 1989.

3. “A Nationwide Inventory of Emissions of Air Contaminants”, Environment Canada, ReportEPS 3-EP-83-10, December 1983.

4. “Metals Mining and Milling Process Profiles with Environmental Aspects, U.S.Environmental Protection Agency, EPA-600/2-76-167, Washington, USA, 1976.

5. “Compilation of Air Pollutant Emission Factors”, U.S. Environmental Protection Agency,EPA AP-42, 4th edition, Research Triangle Park, NC, September 1985.


8.0 LIQUID EFFLUENTS

This section addresses liquid effluents associated with gypsum board production, namely in its rawmaterials extraction and manufacturing stages. The gypsum board manufacturing process itselfgenerates hardly any process effluent. While a large amount of water is mixed with gypsum stuccoto prepare slurry, in the case of 1/2" regular gypsum board, for example, representing about 44% ofthe total raw materials weight, this water is partially chemically bonded in the re-hydration ofcalcium sulfate hemihydrate back to calcium sulfate dihydrate, with the rest of the “water ofconvenience” driven off during the drying process. However, gypsum board plants do use somewater to clean equipment and yards. In addition, rainwater washes away gypsum dust intocontainment areas and this “gypsum board plant” effluent is regularly discharged. As a result,some plant liquid effluents are associated with the gypsum board production and associatedoperations despite the absence of process effluents. While perhaps negligible in comparison to theatmospheric emissions, these effluents should not be ignored.

Furthermore, gypsum board raw materials extraction and preparation is associated with effluentdischarges. Mining or quarrying of gypsum rock generates regular and often fairly substantialvolumes of “minewater” or “quarry effluent”. Sudden storms can also create “stormwatereffluent” at quarries. Preparation of a commercial grade by-product gypsum often requiresadditional washing of the “gypsum cake” that would not be necessary if the by-product werestacked or landfilled. The paper manufacturing process is well known to use large volumes ofwater, although modern near “zero discharge” paper-making operations have reduced the amountof effluent drastically.

We were not able to find any information or references in the literature regarding liquid effluentsassociated with gypsum operations. However, we were able to obtain some detailed monitoring datafrom the Water Resources Branch of the Ontario Ministry of the Environment and Energy fromtheir MISA program1, as well as some additional limited information of similar numbers from theNova Scotia Department of the Environment.2 Further valuable data were supplied by the GreaterVancouver Regional Authority3 and Ontario Hydro.4

8.1 LIQUID EFFLUENT ESTIMATES - GYPSUM BOARD

8.1.1 Raw Materials Extraction

The detailed MOEE information on “minewater” effluent characteristics both in grams per liter ofdischarge, as well as annual loading in kilograms per year, are summarized in Table 8.1. Thesenumbers represent weighted averages of four mining operations. Cursory comparison with limiteddata from Nova Scotia quarries indicate that “quarry effluent” is fairly similar to the “minewater”,and therefore in the absence of more detailed information from various quarries across the country,we will use the Ontario data as representative of gypsum mines and quarries for all regions. Alsoshown in table 6.1 are the monitoring data representing FGD blowdown wastewater treated effluentfrom sand filters at the Ontario Hydro’s Lambton Generating Station before discharging into theequalization ponds. We are assuming that effluent from other by-product gypsum washing wouldhave similar characteristics.


TABLE 8.1 GYPSUM EXTRACTION LIQUID EFFLUENT CHARACTERISTICS1,2,4

Natural gypsum FGD gypsum

minewatertreated effluent from sand filtersbefore discharge to equalization

pondweightedaverage

weighted avg.annual loading

average averageannual loading

Flow [m3/day] 199 - 4010 300Hydrogen ion [pH] 7.78 - 7.94Specific conductance [microS/cm] 1600 - 3100

[mg/L] [kg/yr ] [mg/L] [kg/yr ]

Total suspended solids 28.378 31207.94Aluminum 0.672 891.33 0.050 5.48Zinc 0.008 10.70 0.015 1.64Phenolics 0.002 0.41 0.001 0.11Sulfide 0.017 6.29 0.002 0.22Oil & grease 1.034 1085.62Ammonia & ammonium 0.358 315.16 4.280 468.66Nitrate & nitrite 2.686 2622.88Dissolved Organic Compounds (DOC) 3.615 2781.66Chlorides 42.282 34497.04Sulfates 1044.831 1157168.98

Taking then into consideration the relative use of natural, by-product, and recycled gypsum (seeTable 3.3 in Section 3) in the respective region of the country, Table 8.2 shows, as an example,weighted average effluent loading due to the gypsum extraction by region in g/m2 of 1/2" regulargypsum board. (Data for other types of gypsum board are shown in the summary of this section.)

TABLE 8.2 WEIGHTED AVERAGE EFFLUENT LOADING DUE TO GYPSUM EXTRACTION BY REGION (G/M2 OF 1/2" REGULAR GYPSUM BOARD)


(Vancouver, Calgary) Winnipeg, Toronto) (Montreal, Halifax)

Total suspended solids 0.25371 0.25028 0.23834Aluminum 0.00725 0.00749 0.00726Zinc 0.00009 0.00019 0.00022Phenolics 0.00000 0.00001 0.00001Sulfide 0.00005 0.00006 0.00007Oil & grease 0.00883 0.00871 0.00829Ammonia & ammonium 0.00256 0.03182 0.04120Nitrate & nitrite 0.02132 0.02103 0.02003Dissolved Organic Compounds (DOC) 0.02261 0.02231 0.02124Chlorides 0.28045 0.27666 0.26346Sulfates 9.40744 9.28019 8.83755



In developing estimates for effluents associated with gypsum board manufacturing, two parts of theprocess have to be factored in:

• gypsum paper production, and• manufacturing of gypsum board itself.

Table 6.3 provides average characteristics of gypsum paper producing mill effluent. Major effluentcategories are expressed in both milligrams per liter as well as in kg per day, taking average effluentflow at the time of monitoring sampling into account. To be able to provide, later, effluent loadingper area of gypsum board, Table 8.3 also shows effluent estimates expressed in grams per tonne offinished paper. In our calculations, it was assumed that a paper mill operates six days a week, 52weeks a year, for a total of 312 days per year.

Liquid effluent generated in gypsum board manufacturing operations and its characteristics areshown in Table 8.4. These estimates represent weighted averages of a number of Ontariooperations, and due to the general similarities of gypsum board plants across the industry, it will beassumed that it is representative of all Canadian gypsum board plants.

TABLE 8.3 GYPSUM PAPER PLANT LIQUID EFFLUENT CHARACTERISTICS 3,1

Gypsum Paper Production(averages)

Flow [m3/day] 203.00Hydrogen ion [pH] 4.9 - 8.4Specific conductance [microS/cm] 362.60

[mg/L] [kg/day] [g/tonne of paper]

Total suspended solids 243.40 46.30 270.44089Biochemical Oxygen Demand (BOD) 270.70 55.00 321.25807Aluminum 1.38 0.27 1.57709Zinc 0.36 0.07 0.40887Iron 2.14 0.45 2.62848Copper 1.07 0.24 1.40185Boron 1.72 0.34 1.98596Cyanides 0.10 0.00 0.00000Oil & grease 13.50 2.80 16.35496Manganese 0.12 0.02 0.11682Lead 0.02 0.00 0.00000Molybdenum 0.01 0.00 0.00000Nickel 0.01 0.00 0.00000Silver 0.01 0.00 0.00000Cobalt 0.00 0.00 0.00000Cadmium 0.00 0.00 0.00000Chromium 0.01 0.00 0.00000


TABLE 8.4 GYPSUM BOARD PLANT LIQUID EFFLUENT CHARACTERISTICS 1

Gypsum Board Plant(weighted averages)

annual loadingFlow [m3/day] 4330 - 5500Hydrogen ion [pH] 7.89 - 7.96Specific conductance [microS/cm] 2050 - 2500

[mg/L] [kg/yr ]

Total suspended solids 35.85 75063.91Aluminum 0.32 923.51Zinc 0.00 0.00Phenolics 0.00 0.00Sulfide 0.05 134.92Oil & grease 0.76 1376.26Ammonia & ammonium 0.40 397.22Nitrate & nitrite 1.70 1780.66Dissolved Organic Compounds (DOC) 2.62 6976.95Chlorides 41.39 84293.61Sulfates 1219.60 1156065.79

From the manufacturing effluent monitoring data shown in Tables 8.3 and 8.4, unit factors foreffluent loading expressed in grams per square meter of gypsum board can be estimated. In thedevelopment of these estimates, paper content in various types of gypsum boards was taken intoconsideration (see Table 3.1 in Section 3). As an example, weighted average effluent loading due togypsum board manufacturing steps for 1/2" regular gypsum board is shown in Table 8.5.

The manufacturing effluent estimates can be combined with those for the raw materials extractioneffluent to yield total effluent loading per m2 of 1/2" regular gypsum board, as shown in Table 8.6below. Similar effluent estimates for other types of gypsum board are shown in the summary ofthis section.


TABLE 8.5 WEIGHTED AVERAGE EFFLUENT LOADING DUE TO GYPSUM BOARDMANUFACTURING (G/M2 OF 1/2" REGULAR GYPSUM BOARD)

Papermanufacturing

Gypsum boardmanufacturing

Totalmanufacturing

Total suspended solids 0.12752 0.70549 0.83301Biochemical Oxygen Demand (BOD) 0.15148 0.15148Aluminum 0.00074 0.00868 0.00942Zinc 0.00019 0.00000 0.00019Iron 0.00124 0.00124Copper 0.00066 0.00066Boron 0.00094 0.00094Phenolics 0.00000 0.00000Sulfide 0.00127 0.00127Cyanides 0.00000 0.00000Oil & grease 0.00771 0.01293 0.02065Ammonia & ammonium 0.00373 0.00373Nitrate & nitrite 0.01674 0.01674Dissolved Organic Compounds (DOC) 0.06557 0.06557Chlorides 0.79223 0.79223Sulfates 10.86528 10.86528

TABLE 8.6 TOTAL WEIGHTED AVERAGE EFFLUENT LOADING DUE TO GYPSUM BOARD PRODUCTION (G/M2 OF 1/2" REGULAR GYPSUM BOARD)


(Vancouver, Calgary) Winnipeg, Toronto) (Montreal, Halifax)

Total suspended solids 1.08672 1.08329 1.07135Biochemical Oxygen Demand (BOD) 0.15148 0.15148 0.15148Aluminum 0.01667 0.01691 0.01668Zinc 0.00028 0.00038 0.00041Iron 0.00124 0.00124 0.00124Copper 0.00066 0.00066 0.00066Boron 0.00094 0.00094 0.00094Phenolics 0.00000 0.00001 0.00001Sulfide 0.00132 0.00133 0.00133Oil & grease 0.02947 0.02935 0.02894Ammonia & ammonium 0.00630 0.03555 0.04493Nitrate & nitrite 0.03806 0.03777 0.03677Dissolved Organic Compounds (DOC) 0.08819 0.08788 0.08682Chlorides 1.07268 1.06889 1.05569Sulfates 20.27272 20.14547 19.70283


8.2 LIQUID EFFLUENT - GYPSUM BOARD SUMMARY

Effluent estimates associated with the extraction and manufacturing stages, as well as total effluentunit factors for all ten different types of gypsum boards considered in this study, are summarized inTables 8.7 to 8.11.

8.3 LIQUID EFFLUENT ESTIMATES - FINISHING PRODUCTS

8.3.1 Joint Compounds

According to joint compounds manufacturers, there is no liquid effluent associated with theproduction of either ready mix or setting (dry) joint compounds. Although water is used as a majorcomponent of the ready mix compounds, as the manufacturing process operates as a closed loopsystem, no liquid waste is generated.

Consequently, the only liquid effluent associated with the joint compounds is generated in theextraction (open pit mining) of industrial minerals used as raw materials in their production.Mine/quarry water characteristics for natural gypsum were shown in Table 8.1 above, and we willassume the same effluent characteristics also for gypsum used for production of gypsum plaster forsetting compounds. For the effluent parameters of other industrial minerals used in jointcompounds, mainly calcium carbonate (limestone), we used the numbers provided by the “WaterResources Branch of the Ontario Ministry of the Environment and Energy”,5 and used in the“Cement and Structural Concrete Products” part of the ATHENATM Sustainable DevelopmentProject.6 We will assume that mica, talc and clay have the same effluent loading as limestone. Table 8.11 shows the relevant effluent characteristics for gypsum and limestone quarry water,expressed both in g/mL and in g/tonne of a mineral.

Gypsum and limestone quarry effluent loadings from Table 8.11 were combined with jointcompounds formulations as shown in Tables 3.6 for ready mix compound and 3.7 for the settingcompound to provide the unit factor estimates for effluent loadings associated with these two typesof joint finishing compounds. The results are shown in Table 8.12, expressed in both grams per kgof compound and grams per m2 of board.

8.3.2 Joint Paper Tape

As noted earlier, joint paper tape is produced from the same recycled paper stock as paper forgypsum board facings. Liquid effluent generated in the manufacturing of gypsum paper wasdiscussed in detail above, in Section 8.1.2 (Table 8.3). In this subsection, we will use the samepaper effluent data as derived there, but in addition to mg/L and kg/tonne of paper units we willexpress the liquid effluent also in grams per lineal meter of tape and grams per m2 of gypsumboard (Table 8.13).


TABLE 8.7 WEIGHTED AVERAGE EFFLUENT LOADING DUE TO GYPSUM BOARD PRODUCTION BY PROCESS STAGE (G/M2) - 1/2" REGULAR & TYPE X

1/2" Regular Gypsum Board 1/2" Type X Gypsum Board

West Central E a s t West Central E a s t

Gypsum Extraction

Total suspended solids 0.25371 0.25028 0.23834 0.25259 0.24917 0.23729Aluminum 0.00725 0.00749 0.00726 0.00721 0.00746 0.00723Zinc 0.00009 0.00019 0.00022 0.00009 0.00019 0.00022Phenolics 0.00000 0.00001 0.00001 0.00000 0.00001 0.00001Sulfide 0.00005 0.00006 0.00007 0.00005 0.00006 0.00007Oil & grease 0.00883 0.00871 0.00829 0.00879 0.00867 0.00825Ammonia & ammonium 0.00256 0.03182 0.04120 0.00255 0.03168 0.04102Nitrate & nitrite 0.02132 0.02103 0.02003 0.02123 0.02094 0.01994DOC 0.02261 0.02231 0.02124 0.02251 0.02221 0.02115Chlorides 0.28045 0.27666 0.26346 0.27921 0.27544 0.26230Sulfates 9.40744 9.28019 8.83755 9.36588 9.23920 8.79851

Paper and Gypsum Board Production

Total suspended solids 0.83301 0.82427BOD 0.15148 0.14480Aluminum 0.00942 0.00935Zinc 0.00019 0.00018Iron 0.00124 0.00118Copper 0.00066 0.00063Boron 0.00094 0.00090Phenolics 0.00000 0.00000Sulfide 0.00127 0.00126Oil & grease 0.02065 0.02025Ammonia & ammonium 0.00373 0.00372Nitrate & nitrite 0.01674 0.01666DOC 0.06557 0.06528Chlorides 0.79223 0.78873Sulfates 10.86528 10.81728

TOTAL EFFLUENT

Total suspended solids 1.08672 1.08329 1.07135 1.07686 1.07344 1.06156BOD 0.15148 0.15148 0.15148 0.14480 0.14480 0.14480Aluminum 0.01667 0.01691 0.01668 0.01657 0.01681 0.01658Zinc 0.00028 0.00038 0.00041 0.00027 0.00037 0.00040Iron 0.00124 0.00124 0.00124 0.00118 0.00118 0.00118Copper 0.00066 0.00066 0.00066 0.00063 0.00063 0.00063Boron 0.00094 0.00094 0.00094 0.00090 0.00090 0.00090Phenolics 0.00000 0.00001 0.00001 0.00000 0.00001 0.00001Sulfide 0.00132 0.00133 0.00133 0.00131 0.00133 0.00133Oil & grease 0.02947 0.02935 0.02894 0.02904 0.02892 0.02850Ammonia & ammonium 0.00630 0.03555 0.04493 0.00627 0.03539 0.04474Nitrate & nitrite 0.03806 0.03777 0.03677 0.03789 0.03760 0.03660DOC 0.08819 0.08788 0.08682 0.08780 0.08749 0.08643Chlorides 1.07268 1.06889 1.05569 1.06795 1.06417 1.05103Sulfates 20.27272 20.14547 19.70283 20.18316 20.05648 19.61579


TABLE 8.8 WEIGHTED AVERAGE EFFLUENT LOADING DUE TO GYPSUM BOARD PRODUCTION BY PROCESS STAGE (G/M2) - 1/2" MR & 5/8" REGULAR

1/2" Moisture Resistant Board 5/8" Regular Gypsum Board


Gypsum Extraction




TOTAL EFFLUENT



TABLE 8.9 WEIGHTED AVERAGE EFFLUENT LOADING DUE TO GYPSUM BOARD PRODUCTION BY PROCESS STAGE (G/M2) - 5/8" TYPE X AND MR

5/8" Type X Gypsum Board 5/8" Moisture Resistant Board


Gypsum Extraction




TOTAL EFFLUENT



TABLE 8.10 WEIGHTED AVERAGE EFFLUENT LOADING DUE TO GYPSUM BOARD PRODUCTION BY PROCESS STAGE (G/M2) - 5/16" MH AND 1" SL

5/16" Mobile Home Board 1" Shaftliner


Gypsum Extraction




TOTAL EFFLUENT



TABLE 8.11 WEIGHTED AVERAGE EFFLUENT LOADING DUE TO GYPSUM BOARD PRODUCTION BY PROCESS STAGE (G/M2) - 1/2" AND 5/8" GFB

1/2" Gypsum Fiberboard 5/8" Gypsum Fiberboard

E a s t E a s t

Gypsum Extraction

Total suspended solids 0.32602 0.40452Aluminum 0.00931 0.01155Zinc 0.00011 0.00014Phenolics 0.00000 0.00001Sulfide 0.00007 0.00008Oil & grease 0.01134 0.01407Ammonia & ammonium 0.00329 0.00409Nitrate & nitrite 0.02740 0.03400DOC 0.02906 0.03606Chlorides 0.36038 0.44716Sulfates 12.08843 14.99940

GFB Production


TOTAL EFFLUENT



TABLE 8.12 WEIGHTED AVERAGE EFFLUENT LOADING DUE TO GYPSUM AND LIMESTONE EXTRACTION

Gypsum mine/quarry water Limestone quarry water

[mg/L ofeffluent]

g/tonne ofgypsum

[mg/L ofeffluent]

g/tonne ofCaCO3

Total suspended solids [TSS] 24.22 29.04387 103.70 80.17464Aluminum 0.57 0.82952 0.76 0.26055Zinc 0.01 0.00996 0.00 0.02077Phenolics 0.00 0.00038 0.01 0.00713Sulfide 0.01 0.00585 0.04 0.04669Oil & grease 0.88 1.01034 1.77 2.19849Ammonia & ammonium 0.31 0.29330 1.41 0.73995Nitrate & nitrite 2.29 2.44100 2.90 3.38014Dissolved organic compounds [DOC] 3.08 2.58877 2.49 3.73075Chlorides 36.08 32.10489 1290.03 449.11891Sulfates 891.55 1076.92658 217.71 261.46478

TABLE 8.13 AVERAGE EFFLUENT LOADING DUE TO JOINT COMPOUNDS PRODUCTION

Ready Mix Compounds Setting Compounds

[g/kg ofcompound]

[g/m2 ofboard]

[g/kg ofcompound]

[g/m2 ofboard]

Total suspended solids [TSS] 0.049227 0.033179 0.058261 0.020508Aluminum 0.000160 0.000108 0.000619 0.000218Zinc 0.000013 0.000009 0.000017 0.000006Phenolics 0.000004 0.000003 0.000004 0.000001Sulfide 0.000029 0.000019 0.000027 0.000010Oil & grease 0.001350 0.000910 0.001723 0.000606Ammonia & ammonium 0.000454 0.000306 0.000552 0.000194Nitrate & nitrite 0.002075 0.001399 0.003167 0.001115Dissolved organic compounds [DOC] 0.002291 0.001544 0.003434 0.001209Chlorides 0.275759 0.185862 0.250056 0.088020Sulfates 0.160539 0.108204 0.763933 0.268904


TABLE 8.14 AVERAGE EFFLUENT LOADING DUE TO PAPER JOINT TAPE PRODUCTION

Flow [m3/day] 203.00Hydrogen ion [pH] 4.9 - 8.4Conductance [microS/cm] 362.60

[mg/L] [kg/day] [g/tonneof paper]

[g/meter oftape]

[g/m2 ofboard]

Biochemical Oxygen Demand (BOD) 270.70 55.00 321.25807 0.003939 0.003860Total suspended solids [TSS] 243.40 46.30 270.44089 0.003316 0.003250Oil&grease 13.50 2.80 16.35496 0.000201 0.000197Aluminum 1.38 0.27 1.57709 0.000019 0.000019Boron 1.72 0.34 1.98596 0.000024 0.000024Copper 1.07 0.24 1.40185 0.000017 0.000017Iron 2.14 0.45 2.62848 0.000032 0.000032Manganese 0.12 0.02 0.11682 0.000001 0.000001Zinc 0.36 0.07 0.40887 0.000005 0.000005

REFERENCES

1. Communication from S. Wong / K. Donyina, Ontario Ministry of Environment and Energy(MOEE), re. MISA water effluent discharge data for gypsum plants in Ontario, February 7,1996.

2. Communication from B. Matlock, Nova Scotia Department of the Environment, February 22,1996.

3. Communication from M. de Spot, Greater Vancouver Regional District (GVRD), March 4,1996.

4. Communication from R.S. Daly, Ontario Hydro, February 27, 1996.5. Communication from G. Rees, Ontario Ministry of Environment and Energy (MOEE), re.

MISA water effluent discharge data for cement plants in Ontario, April 19, 1993.6. “Building Materials in the Context of Sustainable Development - Raw Material Balances,

Energy Profiles and Cement and Structural Concrete Products”, CANMET and RadianCanada Inc. for Forintek Canada Corp., February 1994, pp. 36-37.


9.0 SOLID WASTES

In this section we discuss solid wastes associated with gypsum board and related materials. Thegypsum board industry generates remarkably little solid waste. The only production stage wherethe gypsum board industry generates some measurable solid wastes, as any other industry thatmines and quarries its raw materials, is from the raw materials extraction. Essentially, all the wastegenerated in the manufacturing stage is internally recycled back as raw materials or used as sleuttersto support gypsum board pallets.

To balance the picture, the growing trend in using by-product gypsum as a replacement formined/quarried gypsum, as well as the beneficial role of the board industry in recycling and reuseof collected construction gypsum board waste are discussed.

9.1 SOLID WASTES ESTIMATES - GYPSUM BOARD9.1.1 Raw Materials Extraction

Overburden, top soil, and subsoil have to be removed before a new quarry can commence operation.The soil used to be resold, but in modern operations it is stockpiled for eventual quarry reclamationand is not considered waste. In general, quarrying and mining operations can create large amountsof mine spoil — rock material that is not used, but is moved to get to the desired mineral resource.Mine spoils are usually deposited in old surface-mine pits or in mounds. These materials can bephysically stabilized and protected from runoff or leaching to varying degrees, but have neverthelessbeen frequent sources of environmental problems.

In contrast to most mining operations, however, gypsum rock is fairly widely available andmining/quarrying it generates relatively little waste. In comparison with metals mining, for example,there is little or no separating (depending on the amount and nature of impurities), no refining orsmelting of the desired materials from the rock. In the gypsum industry, it is the rock itself that isquite often used in its entirety. In mines or quarries where gypsum rock is contaminated with largervolumes of limestone or dolomite, and it is separated from them, limestone or dolomite is resold andused in road bases or in similar applications. In general, the extraction of gypsum, like otherstructural materials extracted from mines, pits and quarries, results in little environmentalcontamination although the degree of land disturbance can be substantial.1

Based on information obtained from six different gypsum mines or quarries located in all threeregions of Canada, weighted average solid waste, including mine/quarry soil/subsoil overlay,overburden, minespoil and separated impurities (limestone, dolomite, salt, shale), was estimated tobe 336.5 kg/tonne of gypsum rock. (Excluding stripped overlay and overburden, solid wasteimpurities on their own were estimated to be 142.8 kg/tonne of gypsum. This is in good agreementwith U.S. EPA numbers.2) Taking into consideration the fact that 1.2048 tonnes of gypsum areneeded to produce one tonne of stucco (Section 3.1), and the difference in regional usage of naturalgypsum versus the other sources (Table 3.3, Section 3), solid waste unit factors expressed per tonneof stucco were developed for all three regions, and are shown in Table 9.1.


TABLE 9.1 GYPSUM EXTRACTION SOLID WASTE BY REGION

natural gypsumas percentage of total gypsum

supply [%]

solid waste

Solid waste [kg/tonne of natural gypsum] 336.51

Solid waste [kg/tonne of stucco] * 405.43

West Region (Vancouver, Calgary) [kg/tonne of stucco] 86.50 350.68Central region (Winnipeg, Toronto) [kg/tonne of stucco] 85.33 345.94East region (Montreal, Halifax) [kg/tonne of stucco] 81.26 329.44

Note: * if stucco produced from natural gypsum only

As more by-product gypsum will enter the gypsum board production stream replacing some of thenatural gypsum, these solid waste unit factors will undoubtedly diminish in the years to come.


During the gypsum board manufacturing stage about 2 to 5% of the production is culled due tosome operation problems or material being off specifications. However, in contrast to many othermanufacturing processes, the rejected gypsum board is not wasted; virtually all of it is reused.Most of the off-spec board is broken down, shredded and recycled back as a part of the rawmaterials stream into the production. As shown in Table 3.3 in Section 3, such internal gypsumboard waste recycling accounts for about 6%, 4% and 7% of the gypsum sources in the West,Central and East regions respectively.

Some of the waste gypsum board is also cut into strips and used as sleutters to support gypsumboard pallets during storage and transportation, thus eliminating the need to use 4"x4" woodsupport for the same purpose. Any off-spec paper or damaged paper is also recycled, as is thepaper that is on some occasions stripped from the waste gypsum board before it is broken,shredded and fed back into the calciner.

Consequently, there is no solid waste that is associated with the gypsum board manufacturing stage.The only solid waste generated by the gypsum board production is that already identified andestimated above for gypsum mining / quarrying.

9.1.3 Total Solid Waste Due to Gypsum Board Production

The unit factors from Table 7.1, now considered the total solid waste factor estimates, can then becombined with typical average mass of stucco used in formulations of different gypsum boardproducts (Table 3.1, Section 3) to develop estimates for solid waste associated with gypsum boardproduction expressed per m2 of board. (For gypsum fiberboard, it was assumed that use of perlitegenerates about the same amount of solid waste as gypsum.) These estimates are presented inTable 9.2.


TABLE 9.2 TOTAL SOLID WASTE ASSOCIATED WITH GYPSUM BOARD PRODUCTION BY REGION [KG/M2 OF BOARD]

[kg ofstucco/m2]

[kg of solid waste/m2]


1/2" regular gypsum board 6.3610 2.2307 2.2005 2.09551/2" Type X gypsum board 6.3329 2.2208 2.1908 2.08631/2" MR gypsum board 6.9755 2.4462 2.4131 2.29805/8" regular gypsum board 8.3057 2.9126 2.8733 2.73625/8" type X gypsum board 8.4239 2.9541 2.9141 2.77515/8" MR gypsum board 8.9438 3.1364 3.0940 2.94645/16" mobile home board 4.4665 1.5663 1.5451 1.47141" shaftliner 15.6671 5.4941 5.4198 5.16131/2" gypsum fiberboard (GFB)* 8.1738** - - 2.69285/8" gypsum fiberboard (GFB)* 10.1421** - - 3.3412

notes: * includes perlite** GFB is produced only in the East region

9.2 THE USE OF WASTES IN GYPSUM BOARD PROCESSING

It has been already noted (Section 2.6.5) that the gypsum board industry is in a rather uniqueposition in that it can use industrial by-products, construction waste and products made from post-consumers waste paper as a part of its raw materials stream. This recycling and reuse of by-products and wastes is one of the major strengths of the gypsum industry. Westroc’s Mississaugaplant became the first Canadian gypsum board plant operating entirely on FGD by-product/wastegypsum, with a number of other operations supplementing their gypsum rock supply with by-product gypsum, or construction waste gypsum. This trend to increased utilization of by-productgypsum appears to be especially strong in East region plants. It is entirely feasible that bothCGC’s and Westroc’s Montreal gypsum board plants will be operating on 100% by-product /recycled gypsum before the end of 1996.

The availability of free, or very inexpensive by-product gypsum, is changing the gypsum industry.In years to come, it is expected that where it will make economic and geographic sense, more andmore FGD gypsum will be used.3 In 1992 in the U.S.A. over 25.5 GWe of coal-fired powergenerating plants were already operating, under construction, or planned to be equipped with wetlime/limestone scrubbers generating FGD gypsum. It is expected that by the end of the decadesome 7.3-million tonnes of FGD gypsum could be available.6,7 To put that number in perspective,it represents about one-third of the total U.S. annual consumption and almost one-half of itsgypsum mining output. Other sources forecast an eventual U.S. production of synthetic gypsum ashigh as 32-million tonnes annually.8


Increased generation and use of FGF gypsum is a worldwide phenomenon. In Great Britain, FGDgypsum output of just one power station, of the National Power’s Drax station, when fullyoperational in late 1996, will have the capability to supply up to 1,000,000 tonnes of gypsumannually, representing more than one third of the total UK gypsum industry needs.

In Canada 1.5 GWe power generating capacity already is or will soon be similarly equipped withflue gas desulfurization scrubbers capable of generating commercial grade gypsum.5 CanadianFGD gypsum production capability, estimated on the basis of Canadian vs. U.S. wet lime/limestonescrubbing capacity, appears to be in the 500,000 tonnes/year area. This figure seems to correspondwell with the FGD gypsum generating forecasts expected from Ontario Hydro’s Lambton and NewBrunswick’s Belledune power stations.

In at least two Canadian metropolitan areas, Vancouver and Toronto, construction gypsum boardwaste has been banned from landfill sites since the early 1990s. In these areas, the gypsum boardproducers entered into partnership arrangements with recycling companies such as New WestGypsum. Gypsum construction waste is being collected and processed by recyclers, and suppliedback to the gypsum board manufacturing plants. An alternate use for construction waste, accordingto the Gypsum Association, includes agricultural applications and animal bedding material.4

Beneficial re-use of either by-product or waste construction gypsum eliminates some of thepressure on scarce landfill sites.

One leading gypsum board producer certifies that over 20% (by weight) of all gypsum boardmanufactured consisted of recycled material, and that 100% of gypsum waste generated at thatparticular manufacturing facility is recycled.9 The same operation was recognized for itsenvironmental leadership by the Recycling Council of Ontario when it was awarded the 1991Ontario Waste Minimization Award for Outstanding Industrial 3-R’s Initiative.

Table 9.3 summarizes the current distribution of gypsum sources used by Canadian gypsum boardmanufacturers.

TABLE 9.3 DISTRIBUTION OF GYPSUM SOURCES BY GEOGRAPHICAL REGION (%)

NaturalGypsum

SyntheticGypsum

Recycled /external

Recycled /internal

West Avg. 86 0 8 6Central Avg. 85 7 4 4East Avg. 81 10 2 7CANADA 85 6 4 5

Furthermore, as already noted in Section 2.2.3, paper used as facings of gypsum board is madeentirely f rom waste paper (old newspaper, magazines and corrugated cardboard). Therefore,


gypsum board from at least some of the operations is, or can be, 100% recycled or by-products-derived building material.

9.3 SOLID WASTES ESTIMATES - FINISHING PRODUCTSAccording to industry sources, there is no solid waste generated in the manufacturing steps of jointcompounds production, other than bagged raw materials packaging. Paper bags packaging,however, is collected, compacted and sent back to the paper producers for recycling, and is nottherefore considered to be a waste.

Consequently, the only solid waste assignable to the joint compounds production, is the portion ofthe solid waste generated in extraction of industrial minerals used as their constituents. In Table9.1, solid waste of 336.51 kg/tonne of gypsum and 405.43 kg/tonne of stucco (plaster) wereshown. As a rough approximation, we will use the “gypsum” solid waste number for limestone,mica, talc and clay as well. Combining the content of industrial minerals in the joint compoundformulations (Tables 3.6 and 3.7) with these factors, we can provide some indication of the solidwaste associated with joint compounds production (Table 9.4).

TABLE 9.4 SOLID WASTE ASSOCIATED WITH JOINT COMPOUNDS PRODUCTION

Ready Mix Joint Compound Setting Joint Compound

[g/kg of compound] [g/m2 of board] [g/kg of compound] [g/m2 of board]

206.62 139.26 369.94 130.22

REFERENCES

1. “The State of Canada’s Environment”, Environment Canada, Ottawa 1991, p. 11-20.2. U.S. Environmental Protection Agency (EPA), Industrial Process Profiles for Environmental

Use: Chapter 17, The Gypsum and Board Industry, 1977.3. G.J. Venta, R.T. Hemmings, “FGD Gypsum Utilization: A Strategic Approach to Reuse”,

Proceedings, Paper 95-WA80.03, Air & Waste Management Association 88th AnnualMeeting & Exhibition, San Antonio, TX, June 18-23, 1995.

4. “Gypsum Board Systems: Technical Report”, Topic I-9250, AIA Environmental ResourceGuide, July 1993.

5. H.N. Soud, M. Takeshita, “FGD Handbook”, Chapter 4 - FGD Installations on Coal-FiredPlants, IEACR/65 Report, IEA Coal Research, London, January 1994.

6. G.J. Venta, R.T. Hemmings, “FGD Gypsum Utilization: Bridging the “Two Solitudes”,Proceedings of 11th International Symposium on Use and Management of Coal CombustionBy-Products (CCBs), American Coal Ash Association, Orlando, FL, January 15-19, 1995.


7. W. Ellison, R.A. Kuntze, “Expanding of Markets for Gypsum Byproducts”, Proceedings ofSociety for Mining, Metallurgy and Exploration, Inc., 1993 Annual Meeting, Reno, NE.

8. J.A. Walker, “Gypsum - The Miracle Mineral: Brief History and Prospects”, Proceedings ofthe 4th International Conference on Inorganic-Bonded Wood and Fiber Composite Materials,Spokane, WA, September 26-28, 1994, pp.39-40.

9. “Certificate of Recycling”, Westroc Industries Limited, June 1993.

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