Copper Volume 2.pdf

Proceedings

Volume 2 Pyrometallurgy I

Conference organized by GDMB, IIMCh, MetSoc, MMIJ, SME and TMS

Editor

GDMB Paul-Ernst-Strae 10, D-38678 Clausthal-Zellerfeld Internet: www.GDMB.de

Volume 1 ISBN 978-3-940276-25-4 Volume 2 ISBN 978-3-940276-26-1 Volume 3 ISBN 978-3-940276-27-8 Volume 4 ISBN 978-3-940276-28-5 Volume 5 ISBN 978-3-940276-29-2 Volume 6 ISBN 978-3-940276-30-8 Volume 7 ISBN 978-3-940276-31-5

Set (Volume 1+2+3+4+5+6+7) ISBN 978-3-940276-32-2

All rights reserved. No part of this publication may be reproduced or electronically processed, copied or distributed without the prior consent by the editor.

The content of the papers is the sole responsibility of the authors. All papers were peer reviewed by the corresponding members of the technical groups of the organizing societies.

Editorial staff: Dipl.-Ing. Jens Harre Production and marketing: GDMB Informationsgesellschaft mbH

Printed by: Papierflieger

GDMB Clausthal-Zellerfeld 2010

Bibliographische Information Der Deutschen Bibliothek Die Deutsche Bibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliographie; detaillierte bibliographische Daten sind im Internet ber http://dnb.ddb.de abrufbar.

Bibliographic information published by Die Deutsche Bibliothek Die Deutsche Bibliothek lists this publication in the Deutsche Nationalbibliographie; detailed bibliografic data is available in the internet at http://dnb.ddb.de.

Proceedings

Volume 2 Pyrometallurgy I

The Copper 2010-Proceedings are friendly supported by

Proceedings of Copper 2010 IV

The Organizing Society: GDMB Society for Mining, Metallurgy, Resource and Environmental Technology The GDMB is a non-profit organization. Its activities focus on combining science with practical experience in the fields of mining, engineering, tunnelling, mineral processing, extraction, recycling and refining of metals, as well as on the manufacturing of semi and finished products. There is an increasing emphasis on associated environmental issues. The GDMB is internationally active with a European basis and covers a wide variety of topics from applied geology via processing to recy-cling. These include many important areas of chemistry, especially the complex metallurgical chemistry and, last not least, also analytical chemistry. As a consequence of their increasing impor-tance, aspects of industrial minerals are addressed in addition to the traditional fields of metals and alloys. In order to remain a vibrant and attractive professional society, the GDMB draws on the ex-perience and interests of its worldwide members.

The Co-Organizing Societies and their Representatives

Institutos de Ingenieros de Minas de Chile (IIMCh) Enrique Miranda S., Gerente IIMCh, Chile

The Metallurgical Society of the Canadian Institute of Mining, Metallurgy, and Petroleum (MetSoc) Jol Kapusta, Ph.D., Air Liquide Canada Inc., Canada Dr. Phillip Mackey, Xstrata Process Support Centre, Canada

The Mining and Materials Processing Institute of Japan (MMIJ) Dr. Takahiko Okura, The University of Tokyo, Institute of Industrial Science, Japan Yasuo Tamura, Japan Mining Industry Association, Japan

Society for Mining, Metallurgy, and Exploration (SME) Dr. John L. Uhrie, Newmont Mining Corporation, USA

The Minerals, Metals & Materials Society (TMS) Dr.-Ing. Andreas Siegmund, LanMetCon, USA

Proceedings of Copper 2010 V

Conference Chairman Dipl.-Ing. Michael Kopke Aurubis AG, Germany

Technical Programme Chair Dipl.-Ing. Jo Rogiers Aurubis AG, Belgium

Conference Chair Assistance Dipl.-Ing. Jrgen Zuchowski GDMB Gesellschaft fr Bergbau, Metallurgie,

Rohstoff- und Umwelttechnik e. V.

Session Chairs 1 Plenary lessons of general interest Dipl.-Ing. Norbert L. Piret,

for all conference members Piret & Stolberg Partners, Germany

2 Economics Dr. Patricio Barrios, Aurubis AG, Germany

3 Downstream Fabrication, Application Dr.-Ing. Hans Achim Kuhn, and New Products Wieland Werke AG,Germany

4 Mineral Processing Assoc. Prof. Sadan Kelebek, Queens University Canada

5 Pyrometallurgy David B. George, Rio Tinto, USA

6 Hydrometallurgy Dr.-Ing. Andreas Siegmund, LanMetCon, USA

7 Electrowinning and -refining Dr.-Ing. Heinrich Traulsen, Germany Mike Murphy, Xstrata Technology, Australia Mike Hourn, Xstrata Technology, Australia

8 Process Control, Automatization Prof. Dr. Markus Andreas Reuter, and Optimization Outotec Ausmelt, Australia

9 Recycling Dipl.-Ing. Jrg Wallner, Austria

10 Sustainable Development / Health, Dipl.-Ing. Miguel Palacios Safety and Environmental Control Atlantic Copper S.A., Spain

Proceedings of Copper 2010 VI

Technical Group Chairs GDMB (region: Europe, Russia, near Orient) Dipl.-Ing. Jo Rogiers, Aurubis AG, Belgium IIMCh (region: South America) Sergio Demetrio, IIMCh, Chile MetSoc (region: Canada, Australia, Africa) Ass. Prof. Edouard Asselin, University of British Columbia, Canada

MMIJ (region: Japan, China, South East Asia) Dr. Takahiko Okura, The University of Tokyo, Japan

SME / TMS (region: USA, Mexico) Dr. Andreas Siegmund, LanMetCon, USA

Technical Group Members Full information you will find in the internet at: www.Cu2010.GDMB.de

Short Course Organizing Committee Dipl.-Ing. Michael Kopke (Chair), Aurubis AG, Germany Dipl.-Ing. Miguel Palacios, Atlantic Copper S.A., Spain

Prof. Dr. mont. Peter Paschen, Austria Dipl.-Ing. Norbert L. Piret, Piret & Stolberg Partners, Germany

Organizing Committee Dipl.-Ing. Jrgen Zuchowski GDMB Gesellschaft fr Bergbau, Metallurgie, Rohstoff-

und Umwelttechnik e. V. (Copper2010 Organizing Committee Chairman)

Mareike Hahn GDMB Gesellschaft fr Bergbau, Metallurgie, Rohstoff-und Umwelttechnik e. V.

Thomas Marbach GDMB Gesellschaft fr Bergbau, Metallurgie, Rohstoff-und Umwelttechnik e. V.

Dipl.-Ing. Jens Harre GDMB Informationsgesellschaft mbH

Mareike Mller GDMB Informationsgesellschaft mbH

Ulrich Waschki GDMB Informationsgesellschaft mbH

Proceedings of Copper 2010 VII

Preface Copper Indicator of the progress of civilization This is the motto for the 7th international copper conference, the most important copper seminar in the world, which has been organized by the GDMB, the German based Society for Mining, Metallurgy, Resource and Environmental Technology, together with IIMCh from Chile, MetSoc from Canada, TMS, SME from USA and MMIJ from Japan.

The copper conferences bring together the highest level of science and technology: universities, metal producers, manufacturing companies, suppliers and finally the people who work with copper: scien-tists, technicians, engineers, traders and many more.

An extensive programme has been arranged for this conference and an abundance of contributions from all over the world dealing with the different aspects of copper making and its use are registered already, for which we gratefully thank the authors. Apart from plenary addresses, separate sessions will be held for economics, mineral processing, pyrometallurgy, hydrometallurgy, electrowinning and -refining, downstream fabrication and application, process control and automation, recycling and sustainable de-velopment, environmental control, health and safety. Copper, one of the oldest metals used by mankind, is still today one of the most important industrial metals and indispensable for modern life. It is the indi-cator of industrialization and progress in every country. It is used everywhere, where electricity flows and thus is still valued so highly today. The increased economic potential of newly industrialized coun-tries, above all East Asia and China, has increased the significance of the red metal once again. More recent technologies in production, processing and application often provide new answers to old ques-tions. From the middle of the last century there was another innovation surge resulting in totally new technologies, a trend still going on. This has made each copper conference into an exciting adventure. It is positive and reassuring that particularly the high industrialized countries have become the vanguard, not just in technical innovation, but also protection of environment and nature and preserving resources. They repeatedly prove that ecology and economy may go hand in hand.

Many sponsors have contributed to the conferences success, for which I would like to express my sincere thanks!

Hamburg is expecting its guests! Hamburg, the old Hanseatic city with a 1200 year long tradition, one of the biggest and most beautiful cities in Germany, combines a wonderful mixture of industry, com-merce, nature and culture. Not only the Copper 2010 in the Congress Centre awaits you, but rich offerings of sightseeing and shopping in a cosmopolitan city, one of the largest harbours in Europe, the Alster lake in the city centre, green parks and plenty of cultural events, some of which we hope to show you in the companions programme.

We are delighted that you will join us and look forward to a highly interesting conference!

Michael Kopke Chairman Copper 2010

Proceedings of Copper 2010 VIII

Structure of the Proceedings

Volume 1: Downstream Fabrication, Application and New Products Sustainable Development / Health, Safety and Environmental Control

Volume 2: Pyrometallurgy I

Volume 3: Pyrometallurgy II

Volume 4: Electrowinning and -refining

Volume 5: Hydrometallurgy

Volume 6: Economics Process Control, Automatization and Optimization

Volume 7: Plenary lessons of general interest for all conference members Mineral Processing Recycling Posters Authors Index Keywords Index

Proceedings of Copper 2010 IX

Plenary Lectures (Abstracts) Some of the full papers will be published in Volume 7 of the Proceedings of Copper 2010 and in World of Metallurgy ERZMETALL.

Is the Copper Industry Fit for the Future? Dr.-Ing. Bernd Drouven, CEO, Aurubis AG, Hamburg, Germany

The copper world has already changed a great deal during recent years. But what still lies ahead of us? What are the changes in conditions that we have to cope with and how will our solutions look?

The rise in the demand for raw materials is unrelenting. At the same time, both the primary and sec-ondary feed materials have a specific complexity, the customers needs are becoming increasingly differentiated and their orders are placed at increasingly short notice. Production times for metals have to be faster and inventories minimised.

The volatility of the metal prices has increased significantly in recent years and we will probably have to live with that in the future as well. The LME functioned well in the crisis, but the copper price is being influenced more and more by funds.

How can the value added chain change to adapt to this? Which consequences will that have for process technology, production planning and logistics? How will the consolidation of our industry continue?

This keynote will go into the various effects and challenges in particular from the perspective of a European custom smelter and fabricator and present possible approaches for solutions.

Sustainable Growth Strategy for Japanese Copper Business Toshinori Kato, Managing Director, Mitsubishi Materials Corporation, Tokyo, Japan

Business environment, for any industry, has changed dramatically over the last decade. Copper in-dustry is no exception and those involved are experiencing an unprecedented period of upheaval. The landscape of the market has completely altered, with large-scale M&As taking place among miners - creating an oligopoly situation - and a rapid expansion of smelting capacity within de-veloping countries, driven by strong economic growth. Traditional copper smelters and fabricators have been facing challenges, but a long-term sustainability of Japanese copper business is achiev-able.

Firstly, an immense amount of effort has been made over the years to develop the clean and one of the most environmentally-friendly processes in the industry. Mitsubishi Materials (MMC) particu-larly plays a great role in establishing Japanese smelters reputation as the most energy-efficient operations in the world. It is our strong commitment to be a leader in this expertise by sharing our technologies with the industry.

Proceedings of Copper 2010 X

Secondly, infrastructures for copper smelting have been utilized in developing the recycling busi-ness. Exemplified by the operations at Onahama smelter, which has the worlds largest furnace for treatment of shredder residue, the industry has worked closely with other sectors and municipalities. Building an effective structure to make the best use of our facilities is a key for success in this field. It is fair to say that Japanese copper smelters, including MMC, are now regarded as an indispensa-ble part of national environmental policy.

Finally, progression of integration in the copper fabrication sector has strengthened the industrys capability of providing a variety of high-value-added products to end-users. Tight relationships with the consumers have been beneficial in developing new use of copper. Evidence of a promising fu-ture can be seen in increasing use of copper in the growing sectors such as hybrid automobiles and renewable energy.

Copper Sulphide Smelting: Past Achievements and Current Challenges Dr. Carlos M. Daz, Adjunct Professor, University of Toronto, Private Consultant, Toronto, Canada In the last three decades, increased oxygen consumption in copper sulphide smelting and converting and the implementation of computerized process control, among other factors, have led to higher process intensity and smelter concentrate processing capacity, decreased smelting energy consump-tion and improved SO2 capture from process gas streams. An annual primary smelting furnace throughput of one million tonnes of concentrate is the new industry standard. Top submerged lance smelting has become an important processing route in recent years. Two new continuous converting routes were commercialized in the 1990s. However, due to substantially improved converting prac-tice and larger converters, Peirce-Smith converting still maintains its position as the dominant tech-nology.

A major realignment of world copper smelting has taken place in the last 30 years. Spurred by rapid economic expansion and the resulting huge increase in demand for basic materials, a number of modern, large capacity copper smelters have been built in China, India and other Asian countries. Only moderate growth in smelting and electrorefining capacity has taken place elsewhere. More-over, ER cathode output in the USA has substantially decreased.

In this paper, the author examines recent technological advances and industry changes and high-lights issues, such as energy consumption and the corresponding greenhouse gas emissions that will become the focus of future discussion.

Energy as a Key Factor of Sustainability Javier Targhetta, Vice President, Freeport McMoRan, Phoenix, Arizona, USA

Energy must be seen as the prime mover for development and is therefore vital for economic equi-librium and social welfare. Energy will continue to play a key role in the coming decades being not only an environmental challenge but also a fundamental issue in terms of the progress of humanity. Nevertheless, harmonizing several aspects related to energy management will be of essence for the

Proceedings of Copper 2010 XI

near future and will make energy one of the greatest challenges of the 21st century. It is becoming increasingly important to maintain the appropriate equilibrium between environmental issues (global warming, the future of nuclear waste, the integration of renewable energies), coordinated governments policies to ensure that global energy costs are kept competitive and companies finding a balanced, rational and fair model of energy utilization based on the review of ethical business as-pects and the establishment of social responsibility principles.

This paper develops the idea that the rules and procedures for future energy use must be based on a reasonable equilibrium between technical aspects mainly associated to environmental issues, politi-cal decisions made by governments and public administrations and social responsibility pro-grammes that companies themselves must assume and implement.

The Supply and Copper Producer Response to a Growing Demand Scenario Ricardo Alvarez, General Manager, Codelco El Teniente Division, Santiago, Chile

The prospects for medium and long-term consumption of copper are promising. A recovery pro-jected for developed economies, starting 2010, joins the growing impact on demand generated from the process of development and urbanization of emerging countries. The intensity of copper use will also maintain the positive growth started a decade ago based on factors such as providing solutions to combat global warming.

The objective of this presentation is to analyze how supply may react and adjust to envisaged de-mand scenarios, bearing in mind some distinctive elements of the copper industry like:

- Historical supply reaction to demand and price levels - Availability of resources and copper ore reserves, incorporating a dynamic analysis and the ef-

fects of geological exploration and possible technological changes. - Pipeline of probable and possible projects, analysing the effects of projects in less developed and

riskier geographical locations - Technological changes under development that may positively impact the amount of reserves

available and the competitiveness of projects. - The growing role of scrap as a supply source for copper.

The analysis of these points will allow us to confirm the capability of supply response to growing demand, ruling out revisited hypothesis of insufficient reserves

Implementation of Recent Global Copper Projects Tim J. A. Smith, Vice President, Copper, SNC-Lavalin UK Limited, Croydon, Surrey, UK

Despite the recent global recession, a relatively strong copper price combined with continuing sup-ply shortfalls continues to drive the implementation of a number of important new worldwide cop-per projects.

Proceedings of Copper 2010 XII

Along with base metals projects in general, the scale and complexity of such projects has increased such that multibillion dollar projects are increasingly common. Together with expansion projects in the older traditional copper producing regions, new geographic areas are still being opened up. These frequently require major infrastructural development, envi-ronmental and global procurement capabilities as major components of such projects. This plenary session address will examine and discuss the many project management challenges and skills needed to deliver successful projects worldwide, as viewed from the perspective of one of the worlds leading metallurgical plant engineers and constructors.

Proceedings of Copper 2010 XIII

Table of Contents Volume 2

Pyrometallurgy I (Authors A-L)

Design of Copper-Cobalt Sulphating Roasters for Katanga Mining Limited 587 in D.R. Congo Dr. Kamal Adham, Tuisko Buchholz, Alex Kokourine, Rayson Lu, Jim Sarvinis, Andrew Tohn, Stephane Girouard

Filsulfor and Gypsulfor: Modern Design Concepts for Weak Acid Treatment 601 Dr. Angela Ante

Feasibility to Profitability with Copper ISASMELT 615 G. R. Alvear F., P. Arthur, P. Partington

Present and Future Modernization of Metallurgical Production Lines of the 631 Gogw Copper Smelter Leszek Byszyski, Leszek Garycki, Zbigniew Gostyski, Tomasz Stodulski, Jerzy Urbanowski

Energy Consumption in Copper Sulphide Smelting 649 P. Coursol, P. J. Mackey, C. M. Daz

Problems of Lead and Arsenic Removal from Copper Production in a 669 One-Stage Flash-Smelting Process J. Czernecki, Z. mieszek, Z. Miczkowski, G. Krawiec, S. Gizicki

Control of Fugitive Emissions in a Continuous Mitsubishi C-Furnace 685 during Limestone Fluxing Adam Salomon de Friedberg, Alan Hyde, Mark Coleman

Modern Flash Smelting Cooling Systems 699 K. Fagerlund, M. Lindgren, M. Jfs

Proceedings of Copper 2010 XIV

Introduction of a Slide Gate System for Copper Anode Furnaces 713 Dipl.-Ing. Klaus Gamweger

New Highly Efficient Rotary Furnace for Environmentally Friendly 721 Refining Process Dr. Bernhard Hanusch

Sulphur Capacity of the FeO-CaO-SiO2 Slag of Interest to the 731 Copper Smelting Process H. M. Henao, P. C. Hayes, E. Jak

Changes in the ISASMELTTM Slag Chemistry at Southern Peru Ilo Smelter 749 Enrique Herrera, Leopoldo Mariscal

Experimental Study of Phase Equilibria of Silicate Slag Systems 761 M. Phil. T. Hidayat, Dr. H. M. Henao, Prof. P. C. Hayes, Prof. E. Jak

Dryer Fuel Reduction and Recent Operation of the Flash Smelting Furnace 779 at Saganoseki Smelter & Refinery after the SPI Project Mitsumasa Hoshi, Katsuya Toda, Tatsuya Motomura, Masaharu Takahashi, Yushiro Hirai

Development of the Continuous Copper Converting Using Two-Zone 793 Vaniukov Converter E. Jak, L. Tsymbulov

Liquidus Temperature in Calcium Ferrite Slags in Ca2Fe2O5 and Ca2SiO4 811 Primary Phase Fields with Cu and Fixed Po2 E. Jak, B. Zhao, C. Nexhip, D. P. George-Kennedy, P. C. Hayes

Numerical Simulation of Fluid Flow and Melt Temperature in Settler 823 Zhou Jun, Zhou Ping, Chen Zhuo, Liu Anming, Meichi

Proceedings of Copper 2010 XV

Profit Enhancement through Steam Selling 831 Kyoung-Soo Jung, Gun-Woong Byun, Sung-Ho Shin

Gas Injection Phenomena in Converters An Update on Buoyancy 839 Power and Bath Slopping Dr. Jol P. T. Kapusta

Recovery of Valuable Metals from Converter Slags by Reduction with Iron 863 Dipl.-Ing. Stefan Konetschnik, Dipl.-Ing. Helmut Paulitsch, Dipl.-Ing. Dr.mont. Josef Pesl, Ao.Univ.Prof. Dipl.-Ing. Dr.mont. Helmut Antrekowitsch

Waste heat boilers for Copper Smelting Applications 879 Dipl.-Ing. Stefan Kster

Processing of High-Silicon Copper Sulfide Concentrates by 893 Vanyukov Smelting S. M. Kozhakhmetov, S. A. Kvyatkovskiy, E. A. Ospanov, Z. S. Abisheva, A. N. Zagorodnyaya

Boiler Tube Cooling of TSL-Furnace Walls 907 Heikki Lankinen, Rauno Peippo

Experimental Estimation of the Residence Time Distribution 919 in a P-S Converter C. Lpez, A. Almaraz, R. Cuenca, B. Hernndez, F. Reyes, G. Plascencia

Numerical Simulation of Air Blowing into a Copper Matte 931 in a P-S Converter Using a Convergent / Divergent Nozzle C. Lpez, A. Almaraz, I. Arellano, E. Martnez, M. A. Barrn, T. A. Utigard, G. Plascencia

Proceedings of Copper 2010 XVI

Table of Contents Volume 3

Pyrometallurgy II (Authors M-Z)

Sulphide Bath Smelting: 19th Century Concept and Hollways Legacy 945 P. J. Mackey, A. E. Wraith

Large Scale Copper Smelting Using Ausmelt TSL Technology at the 961 Tongling Jinchang Smelter R. W. Matusewicz, Prof. M. A. Reuter, S. P. Hughes, Shengdao Lin, Laisheng Sun

Extending Copper Smelting and Converting Furnace Campaign Life 971 through Technology K. McKenna, C. Newman, N. Voermann, R. Veenstra, M. King, J. Bryant

High Intensity Cast Cooling Element Design and 987 Fabrication Considerations K. McKenna, N. Voermann, R. Veenstra, C. Newman

Management of Copper Flash Smelting Off-Gas Line Gas Flow 1003 and Oxygen Potential Dr. Elli Miettinen, Tapio Ahokainen, Kaj Eklund

The Teniente Converter: A High Smelting Rate and Versatile Reactor 1013 Alex Moyano, Fernando Rojas, Carlos Caballero, Jonkion Font, Marco Rosales, Hugo Jara

Development of Sumitomo Concentrate Burner 1025 K. Nagai, K. Kawanaka, K. Yamamoto, S. Sasai

Review of Process Options to Treat Enargite Concentrates 1035 J. G. Peacey, M. Z. Gupta, K. J. R. Ford

Proceedings of Copper 2010 XVII

Customized Burner Concepts for the Copper Industry 1051 Dipl.-Ing. Michael Potesser, Dipl.-Ing. Burkhardt Holleis, Dipl.-Ing. Dr. Mont. Martin Demuth, Dipl.-Ing. Davor Spoljaric MBA, Dipl.-Ing. Johannes Zauner

Process Optimization by Means of Heat and Mass Balance 1063 Based Modelling at Olympic Dam D. J. Ranasinghe, R. Russell, R. Muthuraman, Z. Dryga

Clyde-WorleyParsons Flash Furnace Feed System: 1079 The Development Cycle Michael E. Reed, Charles U. Jones, Brian Snowdon, Mark Coleman

A Fluid-Dynamic Review of the Teniente Converter 1095 M. Rosales, J. Font, R. Fuentes, A. Moyano, F. Rojas, C. Caballero, R. Mackay

Usage of Colemanite in Copper Matte Smelting 1115 Aydn Ren, Ahmet Geveci, Yavuz Ali Topkaya

Furnace Condition Assessment and Monitoring by Utilization of 1123 Innovative Non-Destructive Testing (NDT) Techniques Afshin Sadri, Ehsan Shameli, Pawel Gebski, David George-Kennedy

Gresik Operation: Past, Present and Future 1143 Hideya Sato, Djoko S. Adji, Antonius Prayoga, Bouman Tiroi S.

FSF Online Process Advisor 1155 Ville Suontaka, Peter Bjrklund

The Development of the Chinese Copper Industry and 1167 Copper Extraction Technology Yao SuPing, Wang Wei

Proceedings of Copper 2010 XVIII

Gas-Gas Cooler as Off-Gas Duct for a Slag Cleaning Furnace: 1173 Example of HSE Progress and Engineering Excellence Michael Strder, Miguel Palacios

Kumera Technology for Copper Smelters 1183 Jyri Talja, Dr. Shaolong Chen, Hannu Mansikkaviita

The Initial Years of the O-SR Process 1199 F. Tanaka, K. Kiyotani, O. Iida

Latest Results of the Intensive Slag Cleaning Reactor for Metal Recovery 1213 on the Basis of Copper A. Warczok, G. Riveros, R. Degel, J. Kunze, M. Kalisch, H.Oterdoom

3D-Refractory Engineering Using the Example of a 1233 MAERZ Tilting Furnace Dr. Christine Wenzl, Dipl.-Ing. Ladislav Koncik, Stefan Ruhs, Dr. Andreas Filzwieser

Ionic Liquids The New Way in Cooling Technology 1247 Dr. Christine Wenzl, Dr. Andreas Filzwieser, Dr. Iris Filzwieser, Eva Raaber

Gold Extraction from Copper Ferrite Residue Produced by 1259 Oxidizing Roasting Copper Matte I. Wilkomirsky, N. Rojas, E. Balladares

Smelting of High-Arsenic Copper Concentrates 1273 I. Wilkomirsky, R. Parra, F. Parada, E. Balladares, Carlos Caballero, Andrs Reghezza, Jorge Ziga

Distribution of Precious Metals between Matte and Slag and 1287 Precious Metal Solubility in Slag Katsunori Yamaguchi

Proceedings of Copper 2010 XIX

Effects of SiO2, Al2O3, MgO and Na2O on Spinel Liquidus in 1297 Calcium Ferrite Slags with Cu and Fixed Po2 B. Zhao, C. Nexhip, D. P. George-Kennedy, P. Hayes, E. Jak

Simulation Study of Intensified Flash Smelting Process 1313 Chen Zhuo, Zhou Jun, Wang Yunxiao, Liu Anming, Meichi

Proceedings of Copper 2010 585

Pyrometallurgy I


Design of Copper-Cobalt Sulphating Roasters for Katanga Mining Limited in D.R. Congo Dr. Kamal Adham, Tuisko Buchholz, Alex Kokourine Stephane Girouard Rayson Lu, Jim Sarvinis, Andrew Tohn

Hatch Ltd. Katanga Mining Limited 2800 Speakman Drive Avenue Industrielle 3207 Mississauga, Canada Kolwezi, D.R. Congo

Keywords: Sulfide ore, copper-cobalt concentrate, sulphating roasting, fluid bed, Finite Element Analysis (FEA)

Abstract In late 2006, Hatch was awarded a contract to supply fluid bed technology for the Katanga Mining Limited (KML) copper-cobalt processing project in D.R. Congo (DRC). The new roasting facility is part of the revitalization of an existing facility in the Katanga Province of the DRC being undertaken by KML. The sulphide ore fed to the roasting plant is treated under the sulphating roast conditions, followed by hydrometallurgical processing. Equipment for the first roasting line has been installed and the plant commissioning is currently (October 2009) underway. Hatch's Flui-dization Technology Group (FTG) in Mississauga, Canada supplied its proprietary equipment and technology to KML under a license agreement, which included the provision of detailed engineering services for the roaster equipment. Hatch offices in Canada and South Africa also conducted the required engineering for the balance of the plant, including off-gas dust and SO2 scrubbers design, civil and structural, piping and ducting, electrical and process controls. This paper only describes the process conditions planned for the sulphating roast operation, and the custom-design features of the fluid bed equipment employed.

1 Introduction Hatchs scope of work involved the design of two eight meter inside diameter (I.D.) copper/cobalt concentrate fluid bed roasters, two fluid bed calcine coolers for product cooling, and the corres-ponding feed and product handling systems for the roaster area. Design of the roaster included com-plete thermal modeling of the roaster shell, roof, tuyere plate and associated expansion joint, gril-lage beam, and windbox, as well as design of the feed injection nozzles, cooling water guns, piping

Adham, Bucholz, Kokourine, Lu, Sarvinis, Tohn, Girouard


and ducting, expansion joints, and discharge solid valves (seal legs). Stress analyses and load condi-tions for several cases were examined, including start-up and upset conditions.

Design of the new roaster lines was based on the KMLs operating experience with the three exist-ing roaster lines, two comprising 4.9 meter I.D. roasters, and one comprising a 7.3 meter I.D. roast-er.

Design of the two new lines also included testwork of the representative feed samples, performed in the Republic of South Africa. Several improvements were made compared to the original roaster design, such as the elimination of transfer boxes for direct solids discharge through seal legs. The transfer boxes were a significant source of maintenance and downtime for KML due to excessive blockages. Seal legs are expected to offer less flow-path restriction, thereby reducing the frequency of blockages.

The installation of the first line is expected to be complete by October 2009, with start-up of the roaster to follow immediately. Design of the second roaster line is well advanced, with the construc-tion work planning currently under consideration.

Alternative technologies and processes were considered during the initial phases of the project. Among them, the use of an autoclave for sulphation of the slurry feed material was considered. However, following technical reviews, KML decided to design the new plant similar to the existing roast-leach concept that had been operating for several decades. As such, fluidized bed technology was selected for the partial roaster design.

The following challenges were addressed during the course of the fluid bed design:

High viscosity and solids content of slurry feed, Hot shell design, to avoid acid condensation, Large roaster diameter, for maximum capacity per roaster, Novel tuyere plate design for improved thermal stress relief.

Due to the shutdown of the existing plant in the late 1990s, much of the 50-year long operational data was unavailable. Limited representative feed ore samples were available, as the rehabilitation of the mine had just begun. Many feed properties needed to be inferred from a limited pool of data. The initial design had to be based on these corollaries until the exact properties could be confirmed through testwork.

In order to optimize the heat balance, it was desired to limit any auxiliary fuel (coal) addition to the roaster. As such, feed slurry was maintained at up to 75 wt. % solids to minimize heat consumption through evaporation of water to superheated vapor. This resulted in a slurry that presented a signifi-cant challenge in the roaster feed system design due to both the high apparent viscosity and the very high solids content.

The presence of sulphur gases in sulphation reactors necessitates a high accuracy of design calculations and precise monitoring of roaster shell temperatures. In order to maintain a sufficient

Design of Copper-Cobalt Sulphating Roasters Katanga Mining Limited


vessel shell temperature to prevent condensation and associated corrosion, while complying with safety requirements for the external surface temperature, the refractory and external insulation ar-rangement and materials were optimized. This optimization was carried out by an iterative steady state heat transfer analysis of the metal cylindrical shell with external and internal thermal insulation and forced/free convection on the internal/external surfaces.

Design of a high temperature fluid bed vessel is governed by the vessel size and key operating conditions. Due to the high throughput requirements, a large diameter roaster (8 m I.D.) was se-lected. This presented a significant challenge through increased deflection of the tuyere plate/grillage beam assembly, due to vertical and horizontal temperature gradients. Several novel design solutions were implemented to overcome this problem including the specialized structural supports for the tuyere plate and the main beams, and the specialized expansion joint between the tuyere plate and the vessel shell.

Design of the tuyere plate, supporting grillage beam, main beam bearing blocks and tuyere plate expansion joint presents a novel approach to the design of fluid bed vessels. Design offers improved distribution of the tuyeres for a more homogeneous introduction of fluidizing air to the roaster while maintaining complete structural integrity of the vessel elements at operating, start-up, shutdown and upset conditions. The developed methodology of analytical and Finite Element (FE) calculations integrated the steady state and transient heat transfer analyses for a hot suspended/slumped bed in-side the refractory lined and externally insulated fluid bed vessel.

Every effort was made throughout the project to comply with the highest standards of health, safety, and the environment. Design was performed to specification according to the South African Bureau of Standards (SABS). Design of the roaster off-gas system was performed to the requirements laid out by the World Bank.

2 Copper/cobalt process overview Ore from two KML mine sites is sent to the Luilu Metallurgical Plant for treatment; an oxide ore originating from open pit mines and a sulphide ore from an underground mine. The average copper and cobalt grades of the sulphide ore from the underground mine is 4.21 % and 0.37 %, respective-ly. Run-of-mine sulphide ore is milled and then concentrated in froth flotation cells. Flotation concentrate is pumped to a thickener located in proximity to the roaster building. Thickener underf-low is filtered and the cake sent to temporary storage. The 75 wt. % solids roaster feed slurry is pro-duced from the stored filter cake in a modified ball mill and fed to the roaster area containing ap-proximately 43 % copper and 4 % cobalt (dry basis). Analysis of the major sulphide components of the feed slurry is given in Table 1.



Table 1: Approximate composition of sulphides in roaster feed (dry basis) Element Cu2S CuS CoS FeS

wt. % 37 15 6 2

Roasting of the sulphide slurry feed produces a dried calcine product that is highly amenable to leaching in the form of oxysulphates of copper and sulphates of cobalt. Cooled calcine product is then sent to the leach tanks, where it is mixed with the recycled spent electrolyte for leaching. Prod-uct of leaching is then filtered prior to the electrolysis.

Downstream processing of sour roast product leads to a significant net generation of sulphuric acid; approximately 220 kg of sulphuric acid is generated for every ton of calcine product produced. This is a large profit driver for the treatment of the open pit (oxide) ore.

2.1 Roaster operation

The roasting area consists of a bubbling fluid bed roaster, fluidized calcine cooler for product cool-ing to 150 C, and ancillary feed and product distribution system. Figure 1 shows a simplified process flow diagram.

Thickened and filtered concentrate is fed to a repulping ball mill ahead of a slurry storage tank. Operation of the ball mill is intermittent, presenting a design challenge in agitation of the tanks. A significant hold-up of slurry is necessary to ensure continuous feed to the roaster during ball mill downtime. As such, the slurry tanks were oversized at a design storage volume of 100 m3, allowing for a 20 hour retention time. Given this large size of tank and high solids content of the slurry to be agitated, design of the agitation tank was carefully performed to ensure the solid particles remained in suspension.

Slurry is then pumped to a roof-mounted surge tank, which provides a density check of the slurry prior to feeding the roaster. Additionally, the surge tank has been designed to maintain a constant head, so as to ensure a continuous, steady flow to the roaster. The roaster roof-mounted feed injec-tion guns atomize the feed to approximately 250 m diameter droplets.

Atomized slurry feed droplets undergo partial drying in the freeboard prior to entering the fluidized bed region. The bed is controlled to a temperature in the range of 650 to 700 C through the use of water sprays mounted on the roof of the roaster for hot bed conditions, and through the use of air-assisted coal injection for cold bed conditions. Under normal operating conditions, the roaster is thermally self-sufficient, with some water required to cool the bed.

A dedicated 800 horsepower fluidizing blower is used to supply fluidizing air to both the roaster and the calcine cooler. Fluidizing air flowrate to the roaster is set at an adequate level of excess air to ensure complete sulphation. The fluidizing blower is designed with a substantial turndown capabili-ty through the use of controllable dampers and an outlet vent for low-flow operation.



Figure 1: Katanga roasting process flow diagram

Roaster off-gas is treated in two parallel, high efficiency cyclones for dust capture before being sent to a scrubber, while the captured dust is fed back to the roaster. The off-gas scrubber uses spent electrolyte for scrubbing to maximize copper/cobalt recovery. The use of water for scrubbing of off-gas dust would dilute the concentration of copper and cobalt in the spent electrolyte, and has a nega-tive impact on the acid balance in the plant.

Solid product is discharged from the roaster via a seal leg and fed to the calcine cooler freeboard, where water sprays maintain a bed temperature of 150 C to cool the calcined product, while main-taining a sufficiently high temperature to avoid localized bed wetting and de-fluidization. Cooler off-gas is passed through a single high-efficiency cyclone for dust removal, prior to being combined with roaster off-gas for scrubbing. Dust removed from the off-gas by the scrubber is sent to a quench tank, where it is mixed with product discharged from the calcine cooler and cooler cyclone capture. The quench tank uses spent electrolyte to maximize recoveries and optimize spent electrolyte use.

A sketch of the fluid bed roaster and calcine cooler, along with auxiliary equipment, is given in Figure 2.



Figure 2: Sketch of fluid bed roaster and auxiliary equipment

2.2 Important chemical reactions

The principle chemical reactions taking place in the roaster are the sulphation of the various sul-phides present in the feed slurry. These include:

4CuS + 7O2 2CuSO4 CuO + 2SO2 Hrxn= -2,226 kJ (1) 2Cu2S + 5O2 2CuSO4 CuO Hrxn= -1,703 kJ (2) CoS + 2O2 CoSO4 Hrxn= -795 kJ (3) 4FeS + 7O2 2Fe2O3 + 4SO2 Hrxn= -2,439 kJ (4)



Additionally, the decomposition of MgCO3 to MgO and CO2 gas, according to reaction 5, is important with regards to the thermal balance in the roaster.

MgCO3 MgO + CO2 Hrxn= 117 kJ (5) All reactions were modeled to thermodynamic equilibrium.

3 Roaster design 3.1 Design basis

Complete heat and mass balances were performed using the software METSIM Version 14.04 for the fluid bed roaster, calcine cooler and ancillary equipment. The design case for the roaster was based on a solids feed rate of approximately 20 t/h (dry basis). Based on historical research per-formed on samples of Katanga ore and concentrate feed slurry as well as on previous plant expe-rience, a bed operating temperature of 680 C was selected.

Based on thermodynamic data, the partial pressure of sulphur dioxide in the roaster bed and the bed gas temperature range have been selected to maximize production of soluble copper and cobalt and minimize production of soluble iron.

Heat input to the roaster is necessary during start-up and is achieved by three removable preheat burners mounted to the roaster sidewall. Once a bed temperature of about 700 C has been achieved, reaction of the sulphide feed slurry with oxygen in the fluidizing air will provide adequate heat to maintain operating conditions, with cooling water needed to limit the bed overheat.

Residence time of solids in the roaster is in the range of 3 to 4 hours for the design case. Research and original pilot plant data performed on representative feed samples indicated a minimum reten-tion time of 3 hours for solids in the fluid bed. An increase in retention time has been shown to increase the decomposition of sulphates; this is especially prevalent for iron sulphates and to a lesser extent for copper and cobalt sulphates.

3.2 Fluid bed sizing

Results of the METSIM heat and mass balance provided the basis for sizing of the equipment. Based on the particle size distribution of the feed as well as particle and gas properties, a minimum fluidization velocity of 0.03 m/s was identified. An actual fluidization velocity of 0.7 m/s was selec-ted to ensure complete fluidization of the bed in the bubbling bed regime, while minimizing solids elutriation to the cyclone.

Based on gas flowrate requirements and fluidization velocities, a roaster diameter of 8 m I.D. was selected. Based on retention time requirements, a bed height of 1.8 m was chosen. Dimensions of the fluid bed were selected to account for design and turndown operation.



As the bed temperature of the calcine cooler is lower than that of the roaster, differing gas properties result in a smaller diameter fluid bed. Consequently, an actual fluidization velocity of 0.67 m/s was selected for the 3 m I.D. calcine cooler at a bed height of 1 m.

Water addition to the calcine cooler must be well controlled due to the proximity of the operating temperature to the evaporation point of water. The large flowrate of water to the calcine cooler presents the potential for cold spots, which can lead to agglomeration of particles and slumping of the bed.

Roaster and cooler freeboard heights were selected based on the transport disengagement height for elutriated bed material. Resultant roaster and cooler internal dimensions are given in Table 2.

Table 2: Roaster and cooler internal dimensions

Parameter Unit Roaster Calcine Cooler

Internal Height (Freeboard and Bed) m 6.4 4.6 Internal Bed Diameter m 8.0 3.0

Internal Maximum Freeboard Diameter m 9.0 3.7

Bed Height m 1.8 1.0

Splash Zone m 1.0 1.0

Freeboard Height m 3.6 2.6

4 Design features 4.1 Roaster vessel

The presence of sulphur in the roaster feed necessitated consideration of sulphur-bearing com-pounds and their associated potential for corrosive attack. Of particular concern is the formation of H2SO4 below the sulphuric acid dew point of 177 C under normal operating conditions. This served as the basis for shell temperature design for the roaster, roaster cyclone, and interconnecting ductwork. Additionally, while a high shell temperature minimizes corrosion, the strength of steel decreases above 200 C. Thus, shell design temperatures were carefully selected in order to minim-ize corrosion while maintaining strength.

Water condensation on the steel shell can induce corrosion and therefore shell temperatures must also be kept above the water dew point of 71 C. Design of the calcine cooler shell considered the water dew point due to the lower operating temperature of 150 C.

In order to meet these shell temperature requirements, design of the roaster was based on analytical and Finite Element thermo-mechanical calculations performed using MathCAD-12, Solid Edge-20 and ANSYS Workbench-11.0 software packages.



The novel design methodology integrated for the first time the steady state and transient heat trans-fer analyses for a hot suspended/slumped bed inside a refractory lined, externally insulated/non-insulated fluid bed vessel. The analysis also encompassed heat diffusion through the refractory lined tuyere plate and windbox, considering forced cooling inside the tuyere stems and participating/non-participating radiative heat transfer gas inside the wind-box. Finite Element Analysis (FEA) was utilized in evaluating the thermo-mechanical stresses in the vessels structural members.

The essential components of this methodology are as follows: Development of a physical model of heat transfer for the suspended/slumped hot fluid bed and

refractory lined tuyere plate with forced cooling of the tuyere stems. Determination of typical load cases including normal operating, start-up, shutdown and upset

conditions. Development of an iterative method of calculations for the system of equations describing the

physical model to define the boundary conditions for the FEA simulations. Calibration of the model by iterative modification of key-values such that the calculated

temperature field matches the experimentally measured numbers for the existing FB vessels. Development of preferred design options for the vessel structural elements. Design enhancement of the vessel components to allow safe operating within allowable stress

intensities and deflections, as set out by international design codes, for the vessel structural members (tuyere plate, vessel shell, grillage beams, supporting brackets, and tuyere plate expan-sion joint) with a minimum life time of 20 years.

4.2 Tuyere and tuyere plate design

As solids throughput requirements necessitated a large diameter (8 meter I.D.) fluid bed roaster, design of the tuyere plate, grillage beam, and associated supports presented a significant challenge.

The tuyere plate consists of over 800 tuyeres to maintain fluidization in the large diameter bed. It was decided to arrange the tuyeres in an evenly distributed, equilateral triangle formation for improved fluidization. Tuyeres are mounted to the tuyere plate through the use of a customized tuyere coupling. This coupling offers a significant reduction in maintenance time and tuyere plate damage during replacement of the tuyeres.

High temperature fluid bed vessels operate at a complex thermo-mechanical load during normal operation, start-up, shutdown and upset conditions. The large size of the KML roaster increases the risk of elevated stresses and large deformations of its structural elements. For example, the radial thermal expansion of the tuyere plate at hot shutdown or malfunction conditions could be a reason for structural failure of the tuyere plate or vessel shell, thus a specially designed expansion joint was required.



Figure 3: Finite element analysis (FEA) stress intensity modeling Deformation of the tuyere plate main beams due to the vertical temperature gradient can damage the tuyere plate and its refractory lining. Thermo-mechanical analysis of the roaster revealed that vertic-al deflection of the tuyere plate for the hot upset case (no fluidization, hot slumped bed in direct contact with tuyere plate refractory, cold fluidizing air flowing through tuyeres) is beyond an ac-ceptable value. Thus, a specialized arrangement for the grillage beam to support the tuyere plate was implemented.

Design of structural supports for the main beams was a challenge due to a large horizontal and vertical deformation under combined thermal and mechanical load. Specially designed bearing blocks were developed in order to resolve this issue.

Due to the complexity of thermo-mechanical interactions between the vessel structural members, vessel structural elements were combined in one large 3D model. The defined load cases were successfully FEA simulated and the vessel design was optimized. A schematic representation of an FEA stress-intensity model is given in Figure 3.



4.3 Removable preheat burners

During normal operation, the preheat burner ports on the roaster sidewall will be plugged and the burners stored nearby. During start-up, the burners are mounted to the ports for firing with diesel. Combustion air is supplied to all three burners by a single, dedicated blower.

Start-up of the roaster consists of firing the burners to achieve the operating temperature of about 700 C. This is performed with an empty roaster and no fluidizing air. Once the set-point is reached, inert seeding material (dried, roasted product or sand) is introduced to the roaster via the coal bin system and slightly fluidized. With a hot bed of inert material, the combustible feed slurry is introduced and the burners are gradually taken off-line. After a period of steady operation, the burners are removed and their ports are plugged.

The selection and use of removable preheat burners rather than fixed burners was due to the potentially corrosive nature of the sulphation process. Similar to the steel shell of the roaster, the preheat burners are subject to potential acid corrosion in the form of sulphuric acid. Removal of the preheat burners during normal operation limits the exposure of the burners to the corrosive envi-ronment. Design includes the use of monorails on the burner level deck to facilitate removal and safe storage of the burners.

4.4 Roof-mounted slurry feed injection system The roaster feed system consists of four slurry feed ports, three operating and one standby, mounted to the roof of the roaster. Each feed port consists of a single nozzle used for the atomization of slur-ry feed with plant air. Design includes control over atomization air flowrate and pressure and an installed purge air delivery system for the prevention of dust ingress to the gun.

Spraying of the feed slurry onto the bed from roof-mounted injection guns allows for significant evaporation of water in the freeboard. This is an important design parameter for the roaster, as low moisture in the bed limits the following agglomerating reaction:

4CuSO4 + Cu2S 6CuO + 5SO2 (6) This reaction occurs between 420 C and 540 C, inhibiting the primary sulphation reaction (2) giv-en above. The presence of moisture surrounding the fine sulphide particles in the feed slurry reduces the particle heating rate. Therefore, the lower the residual surface moisture at the time of contact between the feed particles and the bed, the greater the heating rate of the incoming particles in the bed. This leads to a shorter length of time the particles are in the 420 C to 540 C temperature range, thereby limiting the agglomerating reaction. Partial agglomeration can negatively affect conditions in the fluid bed, potentially leading to defluidization.

While the fluidized bed comprising both solids and interstitial fluidizing gas is maintained at a tem-perature of up to 700 C, roaster off-gas rising from the bed undergoes significant cooling in the



freeboard. This drop in temperature is a direct result of the injection of water from the roof-mounted water sprays.

Due to the nature of the fine-particulate, viscous slurry, selection and design of the roaster feed injection nozzles was critical to the successful operation of the roaster. The particle size distribution of the bed is significantly higher than that of the slurry feed and is a direct consequence of the design of the atomized feed system. Specifically, the bed particle size dis-tribution is determined by the spray properties of the injection nozzles. As such, design of the nozzles was critical to ensure the solid particles had the desired size distribution prior to contact with the bed.

Hatch undertook the design of a custom, vertical down flow, multiphase nozzle for this application. Based on past experience at KML where nozzles were changed every several months, Hatch selec-ted a much harder material of construction to withstand the abrasion erosion caused by the high velocity of solid particulate through the nozzle. Features of this customized nozzle include a jacketed cooling air circuit, mixing of the slurry feed and atomizing air in the injector shaft, and a shallow spray angle. Testing of the custom-designed nozzle confirmed its viability for use in the copper sulphide roaster.

4.5 Product discharge seal legs

Both the roaster and calcine cooler discharge their solid product via seal legs to the calcine cooler and quench tank, respectively. The seal legs permit removal of bed material from the fluid beds at a controlled rate, while also providing a gas seal between the fluid beds and downstream equipment.

Seal legs were designed to be larger than required for product discharge to permit the removal of large pieces of refractory that will inevitably break off the wall due to attrition. Thermal swings arising during start-up and shutdown of the fluid beds typically lead to gradual attrition of refractory. Seal leg design consisted of minimizing plant air consumption, while maintaining sufficient fluidizing air to ensure a reasonable margin between operating flowrate and minimum fluidizing conditions throughout both nominal and turndown operation.

Seal leg rodding ports are available to facilitate maintenance in the event of a blockage. Blockages can be caused by excessively large pieces of refractory breaking off the roaster lining, as well as by settling of solids due to unexpected downtime. Rodding ports allow operators to quickly rod the seal leg, which is often enough to relieve a blockage. Seal legs were also equipped with strainers, which are designed to prevent large solids from entering and blocking the seal legs.



4.6 Windbox cleaning system

During normal operation, erosion or blockage of tuyeres can lead to the accumulation of siftings in the windbox. These siftings are generally fine solid particulate from the fluidized bed. High sifting levels in the windbox can affect the pressure distribution across the tuyere plate and through the freeboard. As such, removal of these siftings is necessary and typically requires shutdown of the operation to allow manual solids removal from the windbox by an operator.

To increase plant availability and facilitate operation, design of the roaster and calcine cooler incor-porated a fully automatic, online windbox cleaning system. Features of the system include level detection in the windbox to obtain online information on the amount of solids in the windbox. Upon reaching a defined setpoint, the solids are discharged from the windbox via a double dump valve, which maintains the windbox operating pressure and therefore does not disrupt the process.

5 Process control philosophy The roaster plant operation is designed as fully automated, with minimum operator intervention requirements. All start-up sequences and their requirements are programmed in a step-by-step man-ner, through an interactive human-machine-interface (HMI). At the start of each sequence, the op-erator will be promoted to verify the readiness of the subsystems that are required for the initiation. Once all the requirements are verified as complete, the operator can remotely action the start.

All the outstanding requirements for system start-up or function are prompted to the operators at-tention. Similar, warnings and alarms are displayed through the HMI. If the operator does not take remedial actions with regards to any critical alarms, the HMI can take step-by-step actions to relieve the alarm, e.g. by turning off a faulty system and switching to a stand-by unit, by lowering the oper-ating load of the roaster, or by placing the faulty system in the idle mode.

6 Start-up and commissioning Construction of the roaster and calcine cooler has been completed in the summer of 2009, with some delays due to prevailing economic conditions in the 2008/2009 period. At the time of the preparation of this paper, installation of the refractory lining is scheduled for completion at the end of October 2009, with start-up and commissioning scheduled to follow immediately.



References [1] THEYS, L.F. and LEE, L.V. (1958): Sulfate roasting copper-cobalt sulfide concentrates: Jour-

nal of Metals: 134-136

[2] THOUMSIN, F.J. and COUSSEMENT R. (1964): Fluid-bed roasting reactions of copper and cobalt sulfide concentrates: Journal of Metals: 831-834

Filsulfor and Gypsulfor: Modern Design Concepts for Weak Acid Treatment


Filsulfor and Gypsulfor: Modern Design Concepts for Weak Acid Treatment Dr. Angela Ante

Bamag GmbH Zum Oberwerk 6 Butzbach, Germany

Keywords: Acid treatment, off-gas, off-gas cleaning, sulfuric acid, SO2, SO3

Abstract The copper smelting process generates a process gas with high SO2, SO3, volatile heavy metals and arsenic loads which is routed to a byproduct sulphuric acid plant for the recovery of marketable sul-phuric acid. In the off-gas cleaning system, SO2, volatile heavy metals and arsenic are removed from the off-gas by wet scrubbing, generating a liquid scrubbing effluent referred to as scrubbing acid or weak acid. The weak acid contains sulphuric acid as well as high concentrations of arsenic and heavy metals.

The conventional treatment process for this liquid effluent stream uses a first neutralization stage to convert the sulphuric acid to gypsum by adding Ca(OH)2 and precipitate the bulk of the arsenic load as calcium arsenate. In a second step, the remaining arsenic is precipitated as ferrous arsenate by adding ferrous sulphate.

Because of the high sulphuric acid concentration of this effluent stream (50 to 100 g/l), the conven-tional weak acid treatment process has the drawback of generating large amounts of gypsum. More-over, the gypsum produced is contaminated with heavy metal impurities, predominantly arsenic. Compounding the problem is that the heavy metal-contaminated gypsum is not leach-resistant so that heavy metals may be resolubilized and released to the environment.

The process concept here presented is a further development of this technology with the aim of quantitatively recovering the sulphuric acid present in the weak acid for reuse as secondary raw ma-terial in the sulphuric acid production process.

Ante


1 Introduction The copper ores contain heavy metals and arsenic. During smelting, a process gas is produced con-sisting of SO2, traces of SO3, HF, HCl, flue dusts containing heavy metals oxides and volatile arse-nic trioxide (As2O3). This process gas is treated to catalytically oxidise SO2 to SO3 for production of marketable sulphuric acid.

The metallurgical gases are cleaned of their harmful constituents in a scrubber system to protect the catalysts and to ensure the required quality of the H2SO4. All constituents soluble in water, espe-cially the SO3, flue dusts and arsenic trioxide, are collected as wastewater known as weak acid.

As in the current conventional treatment process, the sulphuric acid is neutralised to gypsum with the aid of Ca(OH)2 in the first cleaning stage and the majority of the arsenic precipitates as calcium arsenate. In an optional second stage, the residual arsenic is precipitated as iron arsenate through the addition of iron sulphate.

Large amounts of gypsum accrue here, this arising through neutralisation of the sulphuric acid. This gypsum is contaminated with heavy metals, predominantly arsenic, and must undergo expensive disposal. The heavy metals and arsenic can be leached from this gypsum.

BAMAG has therefore developed a process for a Spanish copper producer, in which marketable gypsum can be obtained by means of fractionated precipitation.

The process concept presented here represents a further development with the aim of returning the reusable material (sulphuric acid) originally contained in the wash acid quantitatively or to win a pure gypsum supplying it for reuse as a secondary product.

The arsenic occurring in anionic form at very low pH values is precipitated almost quantitatively by means of sulphide, the majority of the accompanying heavy metals also being separated as precipita-tion products.

In the Filsulfor process the remaining heavy metals occurring in cationic form are retained by nanofiltration. The sulphuric acid obtained exhibits a high marketable quality. Apart from saving disposal space and cost reductions for the sludge treatment, there is also no need for lime and the space requirement is lower.

Another treatment concept is Gypsulfor, the combination of the sulphide precipitation with the neutralization of the decontaminated sulphuric acid with lime producing pure gypsum usable for a wide range of application purposes.

2 Atlantic Copper: technical gypsum production At the Spanish copper smelting plant, approximately 300,000 tons of copper are produced annually from sulphidic copper ore or concentrates.



2.1 Process stages

The process described below comprises the process stages shown in Figure 1. The process is di-vided into technical gypsum production (Part 1; items 1 to 5) and conventional residuals precipita-tion (Part 2; items 6 to 12).

Figure 1: Flow sheet for weak acid treatment plant with technical gypsum production [1] 1 Microfiltration: Separation of coloured solids for the production of a white gypsum 2 Precipitation stage 0: Pure gypsum precipitation takes place by partial neutralisation of the weak acid down to a pH smaller than 1 3 Vacuum belt filter (VBF): The gypsum slurry from precipitation stage 0 is dewatered and washed to a residual moisture content below 35 % 4 Pure gypsum store 5 Filtrate: Filtrate accumulating from dewatering of the gypsum slurry is routed to precipitation stage 1 6 Precipitation stage 1: Gypsum precipitation, coarse As precipitation and heavy metal precipitation with milk of lime 7 Precipitation stage 2: Final As and heavy metal precipitation as hydroxides 8 Clarifier 1 and 2 9 Sludge holding tank 10 Belt filter press (BFP): Dewatering of dirty gypsum 11 Filter cake store 12 Discharge

Weak acid

Ca(OH)2powdered

FeCl3, HCl

Ca(OH)2liquidMicro-

filtration

Vacuum beltfilter

Sludgeholding tank

Belt filterpress

Filter cakestore

Pure gypsumstore

Securedlandfill

Gypsum forsale toindustry

Discharge

Precipitationstage 1


Polyelectrolyte

Clarifier1

Polyelectrolyte

Polyelectrolyte Poly-electrolyte


Clarifier2

Pure gypsum production Residuals precipitation

1

2

3

4

5

67

8

9

10

11

12

Ante


In fact, approx. 85 % of the produced solids are sold as technical gypsum and only 15 % are to un-dergo costly disposal at a secured landfill [1].

2.2 Disadvantages

In order to obtain marketable gypsum (u. a. < 100 ppm arsenic), a part of the sulphuric acid is re-quired to set a low pH value in the technical gypsum precipitation stage so as to retain the arsenic in soluble form corresponding to the dissociation weight. The residual amount of sulphuric acid is not converted to gypsum until the neutralisation stage together with the heavy metals and the arsenic and must be disposed of cost-intensively as "waste sludge".

Moreover, technical gypsum is a "bulk product" whose use is restricted to consumers located nearby owing to relatively high transport costs. The disposal safety is therefore restricted from the view-point of the producer. Technical gypsum must occasionally be disposed of cost intensively.

Economic reasons mean that application of the technical gypsum process is restricted to weak acids streams with a considerably high content of sulphuric acid and low concentrations of contaminants.

In addition, the heavy metals can be leached from this gypsum contaminated with heavy metals.

Furthermore, the potential recovery of valuable heavy metal hydroxides from the calcium arsenate embedded in a gypsum matrix is technically difficult and therefore not economically feasible.

3 Process development 3.1 Process requirements

Due to these disadvantages BAMAG searched for a new process design.

Our innovative project bases on the following process requirements: Separation of the sulphuric acid from heavy metals and Arsenic

Process with high driving force

Recovery of a technical sulphuric acid for use of low or moderate quality requirements if ever possible

In Table 1 the processes are summarized which were discarded after theoretical evaluation of their principal technical applicability. Some of them were additionally investigated by simple lab tests.



Table 1: Discarded Processes [2] Process Reason for exclusion Adsorption process Iron hydroxide process pH 5-9 Pisolite pH 6.5 Retardation As removal

Ante


Table 2: Some solubility products of metals at 25 C [3, 4] Formula Solubility product Formula Solubility product PbS 3*10-28 Pb(OH)2 4.2*10-15 CdS 5.1*10-29 Cd(OH)2 2*10-14 FeS 3.7*10-19 Fe(OH)2 1.8*10-15 CuS 8*10-45 Cu(OH)2 1.6*10-19 NiS 10-26 Ni(OH)2 1.6*10-16 Ag2S 1.6*10-49 Ag(OH) 2*10-8 ZnS 6.9*10-26 Zn(OH)2 4.5*10-17 SnS 10-20 Sn(OH)2 3*10-27

Figure 2 shows that the residual solubility of the sulphides at low pH values is significantly lower than the corresponding residual solubility of the hydroxides. Above all, the main decontaminate arsenic has a residual solubility below 3 mg/l up to a pH value of 2.

Figure 2: Dependency of the residual solubility on the pH value during H2S precipitation [5] The sulphide precipitation of heavy metals and arsenic is, in principle, possible with Na2S, NaHS and H2S as well as some organic sulphides. The use of Na2S is initially accompanied by neutralisa-tion of the sulphuric acid (see Equation 1): Na2S + H2SO4 ==> Na2SO4 + H2S (1)



This is followed by the actual sulphide precipitation in Equation 2 with the example of arsenic As:

3 H2S + 2 H3AsO3 ==> As2S3 + 6 H2O (2) When using NaHS the available hydrogen equalises the basic effect of the sodium, the pH value only shifting minimally during the addition of NaHS.

The use of gaseous H2S would be highly advantageous from a technical point of view, as excess educt would be trapped and hence reusable. However, this gas is highly toxic and therefore requires extremely high safety standards, not only during application in the process, but also during transport and storage, thereby making its use infeasible [4].

3.2.2 Nanofiltration

The nanofiltration was tested, as it is capable of retaining 2-valent cations at relatively moderate pressures (5-30 bar or rather 5105-30105 Pa) owing to its specific separating effect, while, how-ever, letting water and sulphuric acid through.

Nevertheless, arsenic cannot be separated via nanofiltration because the selectivity is much too low, as 3-valent arseniate is present uncharged or with a single negative charge and can hence pass through the membrane in the same way as sulphuric acid at very low pH values.

A certain degree of Arsenic retention can be explained by the fact that the arsenic molecule together with its hydrate envelope is larger than the sulphuric acid molecule and can hence pass through the membrane.

Furthermore, the arsenic concentration in the example examined is so high that scaling occurs at a retention of 50 % and higher, as the solubility limit of around 20 g/l is exceeded.

The nanofiltration is therefore suitable as an after-treatment stage after the sulphide precipitation in order to clean the remaining heavy metals from the sulphuric acid [2].

4 Investigations by BAMAG All investigations were carried out with a sample of original weak acid from a copper smelter of Chile. All theoretical and practical investigations as well as mass balances were carried out on the basis of the composition of the weak acid of this smelter.

4.1 Sulphide precipitation

In Table 3 some typical precipitation results are summarized.

With these pre-investigations without any optimization the residual concentration of copper, lead, tin and molybdenum met already the requirements, whereas the parameters has to be optimized for

Ante


meeting the maximum values for As before the realization of this process. Nevertheless more than 99.9 % of the As load had been precipitated.

Table 3: Depiction of some analysis of precipitation

Parameter Start value [ppm]

End value [ppm]

Cleaning [%]

Precipitable

Arsenic 11,000 6.9 100 Copper 634 0 100 Lead 86 0.1 100 Tin 430 0.2 100

Molybdenum 109 0.2 100

Partially precipitable

Iron 189 160 15

Not precipitable Aluminum 49 49 0 Zink 219 210 0

Unknown Cadmium n.a. n.a. Chromium < 1 0.2 n.a.

Nickel < 1 0.2 n.a.

Sodium 97 34,320 accumulation

4.2 Nanofiltration

Due to the advances on the field of material quality for membranes since membrane for nanofiltra-tion are actually available allowing the application even for such a critical media as weak acid char-acterized by a negative pH value and a concentration of fluoric acid up to than 3 g/l. Two of these new membranes were investigated which were theoretically resistant to the medium.

The investigations took place in a dead-end batch filtration lab plant with an agitated reactor. The nanofiltration system used was operated using a filter with 36.3 mm diameter and a filling volume of 200 ml [6].



4.2.1 Resistance of the membranes

After 18 days, no significant change could be determined in the clarified water flow, which would have occurred in the case of damage. This result provides a starting point for the acid stability, but does not permit any conclusion regarding the long-term performance.

4.2.2 Removal of heavy metals

The efficiency of the nanofiltration to remove the contaminants of the weak acid was investigated and the results are shown in Figure 3.

Figure 3: Depiction of the retention of heavy metals and sulphuric acid (SA) The retention at 22 C was significantly higher than at 45 C for all heavy metals, as the temperature dependency of the diffusion is considerably greater than the flow.

Fe, Zn, Cu, Mo und Al can be retained well at room temperature (> 95 %). The retention of Pb and Sb is poor.

As the metals Fe, Zn and Al are primarily to be reduced after the sulphide precipitation, the nanofil-tration is ideally for the production of high-quality sulphuric acid through after-cleaning.

-20

0

20

40

60

80

100

Fe Zn Al Cu Mo Sb Pb SA

Compound

Re

ten

tion

[%

]

22 C45 C

Ante


In all tests, the retention increased with the pressure (not shown), as the flow increases through the pressure increases. However, the diffusion speed, by means of which the dissolved contents can pass the membranes, remains constant.

5 Modern design concepts 5.1 Filsulfor

In the subsequent Figure 4 the principle of the new process concept design Filsulfor is shown.

Figure 4: Flow diagram for weak acid treatment plant with sulphide precipitation

The process can be divided into two parts. Part 1 deals with the precipitation of the bulk of heavy metals and arsenic (items 1 to 3) with the sludge handling (items 4 to 5) and part 2 with the subse-quent nanofiltration for the water treatment (processes 6 and 7). 1 Precipitation: Precipitation of Arsenic and the majority of heavy metals with NaHS 2 Clarifier: Separation of the precipitation products from the weak acid

3 Aeration: Elimination of the by-product H2S

4 Belt press: Sludge dewatering

5 Waste sludge basin: Storage of waste sludge

6 Filtration: Protection of the membranes against solids in the overflow of 2

7 Nanofiltration: Separation of remaining heavy metals (concentrate) from the sulphuric acid (permeate)



5.2 Gypsulfor

In the subsequent Figure 5 the principle of the new process concept design Gypsulfor is shown.

Figure 5: Flow diagram for weak acid treatment plant with sulphide precipitation

The process is divided as well into two parts. Part 1 remains the sulphide precipitation with the pre-cipitation of the bulk of heavy metals and arsenic (items 1 to 5) and part 2 is the subsequent pure gypsum precipitation (items 6 and 7) with the handling of the produced pure gypsum. 1 Precipitation: Precipitation of Arsenic and the majority of heavy metals with NaHS 2 Clarifier: Separation of the precipitation products from the weak acid

3 Aeration: Elimination of the by-product H2S

4 Belt press: Sludge dewatering

5 Waste sludge basin: Storage of waste sludge

6 Filtration: Protection of the secondary product against solids in the overflow of 2

7 Pure Gypsum Precipitation: Neutralization of the sulphuric acid with milk of lime

8 Vacuum belt filter: Gypsum washing and dewatering

9 Gypsum storage

NaHS

Weak Acid

Clarifier

Belt

Press

Aeration Precipitation

Waste Sludge

Ca(OH)2powdered

Micro-filtration

Vacuum belt filter

Pure gypsum

store

Gypsum for Sale to Industry

Precipitation stage 0

1 62 3

4

5

7 8 9

Ante


6 Evaluation 6.1 Discussion of the process

In Figure 6 the overall mass balance for Filsulforfor a real copper plant is exemplarily shown and in Figure 7 the mass balance for Gypsulfor.

Figure 6: Overall mass balance for Filsulfor

WWTP

Purified sulfuric acid(for reuse)

Waste sludge1 t/h

contaminated with

heavy metals

(60 % DS)

NaHS1 t/h (DS = 40 %)

Weak acid

V = 20 m3/h As = 300 kg/h Me+= 244 kg/h H2SO4 = 3,940 kg/h

V = 18.8 m3/h As = > 0 kg/h Me+ = 12 kg/h H2SO4 = 3,550 kg/h

V = 2.1 m3/h As = > 0 kg/h Me+ = 167 kg/h (Zn and Fe) H2SO4 = 390 kg/h

Waste water



Figure 7: Overall mass balance for Gypsulfor

7 Outlook 7.1 Filsulfor

Sulphuric acid is anyway a product which is produced as by-product in large quantities by the cop-per smelters. Therefore, the sale of sulphuric acid is a routine process and the number of clients is much higher than for technical gypsum. An additional external client is not necessary.

Another potential use of the dissolved sulphuric acid produced involves the internal application for the leaching process completely avoiding external sale. It therefore safeguards the supply.

7.2 Gypsulfor

The Gypsulfor treatment concept is suitable for sites where the secondary raw product is used on site itself or where the secondary raw product gypsum is sellable. This is given mainly when the copper plant is in vicinity to the sea offering the cost efficient transportation of the bulk product.

WWTP

Pure gypsum(for reuse)

Waste sludge1 t/h

contaminated with

heavy metals

(60 % DS)

NaHS1 t/h (DS = 40 %)

Weak acid

V = 20 m3/h As = 300 kg/h Me+= 244 kg/h H2SO4 = 3,940 kg/h

0.84 t/h As < 1 mg/kg

V = 53 m3/h As < 1 mg/l

Waste water

Ante


The presented design concepts can contribute to the efforts of mankind to recycle secondary by-products and to preserve natural non-renewable and exhaustible sources mainly for gypsum because its winning causes extensive damages to the environment.

7.3 Further steps

For individual projects the cost reduction potential in accordance with local conditions has to be considered such as the reduction of reagent costs of NaHS for the sulphide precipitation, the reduc-tion of the membrane exchange and energy costs for the nanofiltration.

As the economy of the whole treatment plant is strongly dependant from the local conditions and regulations these studies have to be done for each site separately taking into account the particular situation. Mainly the treatment or disposal of the liquid and solid residues of the processes is to be discussed, e.g. the concentrate (10 % of the input volume stream) deriving from the nanofiltration step.

The different process concepts refer to the possible combination of treatment stages. The described sulphide precipitation stages can be realized with different reagents and can be combined either with the nanofiltration or with the technical gypsum precipitation. In the later case it has to be investi-gated if the neutralisation and /or the precipitation with ferrous compound are still necessary to meet the national and international requirements.

References [1] ANTE, A., SCHNBRUNNER, S. (2005): Production of marketable gypsum from waste weak acid

- World of Metallurgy, 2: 75-82; Clausthal-Zellerfeld.

[2] EICHMANN, C. (2007): Trennung von Arsen und Schwermetallen aus Waschsure, master the-sis, Butzbach.

[3] C. E. MORTIMER (2001): Chemie Basiswissen der Chemie, 7. korrigierte Auflage, Georg Thieme Verlag.

[4] HARTINGER, L. (1991): Handbuch der Abwasser und Recyclingtechnik, Wilhelm Ernst & Sohn [5] RAMACHANDRAN V. (2007): Processing of aqueous effluents in the copper industry, One day

short course in Toronto, Canada the 26th of Sep 2007; Toronto.

[6] RGENER, F. (2007): personal information and correspondance, BFI, the 20th of Mar 2007; Dsseldorf.


Feasibility to Profitability with Copper ISASMELT G. R. Alvear F., P. Arthur, P. Partington

Xstrata Technology Level 4, 307 Queen Street Brisbane 4000, Australia

Keywords: Pyrometallurgy, Top Submerged Lance (TSL), ISASMELTTM, copper, southern Peru

Abstract The ISASMELT Top Submerged Lance (TSL) bath smelting process was developed in Mount Isa, Australia by Mount Isa Mines Limited (now a subsidiary of Xstrata plc) during the 1980s. It is now successfully commercialized and has become the technology of choice for many new smelters and smelter modernization projects, being extremely cost effective for smelting both copper concen-trates and secondary materials. Ten copper smelters are now operating the process around the world.1Two new furnaces were commissioned in 2009, while three more furnaces are under con-struction and are scheduled to be commissioned during 2010 and 2011.

Production capacities of more than 330,000 tonnes per year of copper are being achieved through a single ISASMELT furnace with instantaneous feed rates reaching up to 200 t/h.

Process development continues on the commercial scale plants at Mount Isa and elsewhere around the world. By employing the design and operational experience gained by Xstrata over more than 25 years of process development ISASMELT plants can be constructed in remote locations in a relatively short time and achieve rapid ramp up to design capacity with limited technical resource. As the family of ISASMELT licensees grows the members are able to share and capitalize on the knowledge and experience with their peers around the world.

This paper reports on copper ISASMELT projects completed in recent years and how licensees have progressed from feasibility studies to profitable operations using Xstrata Technologys tech-nology transfer process.

1 Introduction It was in 1975 when Mount Isa Mines Limited (MIM) set its sights on a new development occurring at CSIRO in Australia: the Top Submerged Lance (TSL) technology, a new concept for smelting

Alvear, Arthur, Partington


using the Sirosmelt lance. MIM joined forces with CSIRO and participated in lab scale trials of the technology.

At that time, MIM was looking for new technologies that could be applied to its lead and copper smelter operations to reduce operating costs while improving the environmental performance. MIMs Mount Isa lead smelter used a sinter plant and blast furnace for lead bullion production, while the copper smelter used a fluid bed roaster and two reverberatory furnaces to produce copper matte. The matte was then converted to blister copper using Peirce-Smith converters [1]. MIM was seeking alternative smelting processes that would produce off-gases with higher SO2 con-tent so that the smelter gases could be treated and sulphur captured in an acid plant. MIM also needed to find a process with lower operating costs to remain cost effective with the steady decline in real metal prices.

While keeping an eye on the development of other technologies MIM, jointly with CSIRO, devel-oped the concepts of the Lead ISASMELT and Copper ISASMELT processes. These were pi-lot tested on a 250 kg/h test rig in Mount Isa in the early 1980s.

From the completion of the pilot scale tests a long history unfolded involving a multidisciplinary team of visionaries, who saw the technical and business potential that ISASMELT technology could offer. Over the years ISASMELTTM has progressed from a 250 kg/h pilot plant scale to indus-trial facilities that can run up to 200 t/h and treat a variety of materials including nickel, lead and copper concentrates and secondary materials [2-4]. Since the first plant was built at Mount Isa, twenty ISASMELT plants have either been con-structed or are under construction. Figure 1 shows the location of the commercial plants that have been licensed to date.

An important milestone in the market consolidation of the technology was when MIM became part of Xstrata plc in 2003. At that time MIM Process Technologies, the division that was responsible for the commercialization of the technology, became Xstrata Technology (XT). XTs mission was to market the core technologies developed in Xstratas operating sites: IsaMill and Jameson Cell technologies in mineral processing, ISAPROCESS for the electrorefining and electrowinning of copper, the Albion atmospheric leaching process and the ISASMELT and ISACONVERT technologies for the smelting and converting of non-ferrous materials.

Feasibility to Profitability with Copper ISASMELT


Figure 1: Location of ISASMELT plants licensed to date

During 30 years developing and operating ISASMELT technology on large scale plants, signifi-cant technical improvements have occurred in areas such as furnace design, feed preparation sys-tems, off-gas handling, operating and process control strategies, refractory management, operator training and commissioning systems. The combination of experience led to the development of the ISASMELT technology package that is licensed to external clients today [5]. Many of the im-provements implemented by plant operators have been passed on to, and adopted by, other licen-sees. Exchange of ideas and technical improvements occurs through visits to fellow licensee sites and through regular licensee workshops arranged by XT at locations close to the ISASMELTTM in-stallations, the most recent being at Arequipa, Peru in 2008 shown in Figure 2. It included a visit to the Southern Peru Copper Corporation (SPCC) ISASMELTTM plant.



Figure 2: Licensee workshop in Arequipa, Peru, October 2008

2 The ISASMELT principle 2.1 ISASMELT concept

ISASMELT technology is based on the use of an elegant furnace design which is readily enclosed to eliminate emissions to the surrounding environment. It uses submerged lance injection technolo-gy to provide highly efficient mixing and reaction of feed materials in a molten slag bath. The use of an advanced process control system results in the furnace operation being largely automated.1Being a vertical furnace with a small footprint it can be easily retrofitted into existing smelters to either augment or replace existing technology. The furnace concept is shown in Figure 3.

Feasibility to Profitability with Copper ISASMELT


Figure 3: ISASMELT process concept

2.2 Copper ISASMELT reaction mechanism

The Copper ISASMELT process is a slag reaction process, where fresh feed is digested into the molten slag phase. It is in this phase where the main chemical reactions occur and oxidation of the feed takes place.

The oxygen transfer process is achieved through the controlled oxidation of the slag (FeO) and sub-sequent formation of magnetite (Fe3O4) as shown schematically in Figure 4. It is the liquid oxy-gen from the magnetite (Fe2O3FeO) that reacts with the concentrate and fluxes to form copper matte, a fayalite slag and SO2 gas.



Figure 4: Copper ISASMELT reaction mechanism

2.3 Slagmatte separation: the role of the Rotary Holding Furnace

Copper matte and slag generated from the reactions occurring in the Copper ISASMELT furnace are tapped and mechanically settled in a separate furnace. The type of settling furnace will depend on the economics of each operation. XT supplies a proprietary technology known as the Rotary Holding Furnace (RHF). This process was developed at MIM and is cur

Copper Volume 2.pdf

Documents

Transcript of Copper Volume 2.pdf