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We’ve got A Lot To Offer Our Silicates Customers.

OxyChem

Users of Sodium Silicates will recognize the

value and utility of a practical handbook,cov-

ering the proper methods of handling, storing

and using this important chemical. This

information has been prepared to meet the

needs of technical and plant personnel who

require operating data in their

work, with minim um effort required

for its interpretation.

Buyers and other interested

individuals desiring information on

Sodium Silicate Liquids, Sodium Silicate

Glass Briquettes,or Sodium Metasilicates will

find most of their questions answered

in this handbook. For the laboratory person,

basic information has been included on

analytical procedures. If further assistance is

needed pertaining to Sodium Silicates,

OxyChem’s sales,technical service and

tr affic departments are available by

contacting your nearest OxyChem location as

listed on the inside back cover of this hand-

book.

Foreword

OxyChem Silicate Plants

OSHA Star Plant: The highest honor for excellence in safety performance awarded by the Occupational Safety and Health Administration.

1

Plant Locations................................Back CoverIntroduction ...................................................2

Manufacturing Process..................................3

General Applications......................................4

Pr inciple Uses.................................................5

Specific Applications......................................9

Pr inciple Grades

Liquid ........................................................11

Sodium SilicateGlass Briquettes........................................11

Sodium Metasilicates................................12

Safety Procedures...........................................13

Storage and Handling....................................13

Unloading Tank Cars.....................................14

Tank Trucks....................................................15

Steel Drums....................................................15

Storage............................................................16

Pumps,Valves and Piping.............................16

Handling Sodium Metasilicates....................16

Technical Data...............................................18

Methods of Analysis......................................21

IMPORTANT: The information presented herein, while not guaranteed, was prepared by technical personnel and is true and accurateto the best of our knowledge. NO WARRANTY OF MERCHANTABILITY OR OF FITNESS FOR A PARTICULAR PURPOSE, OR WARRANTY OR GUARANTY OF ANY OTHER KIND, EXPRESS OR IMPLIED, IS MADE REGARDING PERFORMANCE, SAFETY, SUITABILITY, STABILITY OR OTHERWISE. This information is not intended to be all-inclusive as to the manner and conditions ofuse, handling, storage, disposal and other factors that may involve other or additional legal, environmental, safety or performance considerations,and Occidental Chemical Corporation assumes no liability whatsoever for the use of or reliance upon this information. While our technicalpersonnel will be happy to respond to questions, safe handling and use of the product remains the responsibility of the customer.No suggestions for use are intended as, and nothing herein shall be construed as, a recommendation to infringe any existing patents orto violate any Federal, State, local or foreign laws.

The OxyChem Sodium Silicates Handbook

Contents

Foreward

Users of Sodium Silicates will recognize the value and utility of a practical handbook,covering the proper methods ofhandling, storing and using this important chemical. This information has been prepared to meet the needs of technicaland plant personnel who require operating data in their work, with minimum effort required for its interpretation.Buyers and other interested individuals desiring information on Sodium Silicate Liquids,Sodium Silicate GlassBriquettes,or Sodium Metasilicates will find most of their questions answered in this handbook. For the laboratoryperson,basic information has been included on analytical procedures. If further assistance is needed pertaining toSodium Silicates,OxyChem’s sales,technical service and traffic departments are available by contacting your nearestOxyChem location as listed on the inside back cover of this handbook.

2

Sodium SilicatesSodium silicate is the generic name for a series ofcompounds derived from soluble sodium silicate glass-es. They are water solutions of sodium oxide (Na2O)and silicon dioxide (SiO2) combined in various ratios. Varying the proportions of SiO2 toNa2O and the solids content results in solutions withdiffering properties that have many diversified industrial applications.

Occidental Chemical Corporation’s standard commercial grades of liquid sodium silicates range inweight ratio of SiO2 to Na2O from 1.6 to 3.3.

In addition to liquid sodium silicates,OxyChemproduces sodium silicate glass briquettes,as well asmetasilicates in granular anhydrous (S-25®) and pentahydrate forms (Uniflo®26). Glass briquettes aredissolved on-site by some large volume consumerswhen freight savings can justify the equipment andlabor costs involved. The sodium metasilicates areprimarily used in cleaning compounds. Special technical bulletins for these compounds are availableon request.

Sodium silicate glass is made by fusing high puritysilica sand and soda ash in open hearth furnaces at1300oC/2400oF. The molten glass is cooled, fractured,and charged into vessels where it is dissolved underpressure by hot water and steam. The various gradesof liquid sodium silicate are produced by varying thealkali/silica ratio and the solids content.

OxyChem’s silicate plants are located throughout theUnited States and are within convenient shipping dis-tances of all major industrial areas.

Introduction

3

Sodium Silicate Manufacturing

Sand Soda Ash

Fuel Furnace 24000F

50%Caustic

SodaWater /Steam Dissolver

Adjust RatioAnd Solids

LiquidSilicateStorage

Dryer

GranularMeta

Silicates

4

General Applications

This list includes both major and minoruses for silicates. The uses noted illus-trate the wide range of applications forsodium silicates.

Abrasive WheelsAbsorbentsAdhesivesAsbestos Products

Bar SoapsBeater Sizing of PaperBleaching Textiles & PaperBoiler CompoundsBrick-MakingBriquetting

CoalGlassOres

Buffering AgentBuilding Materials

Acoustical InsulationBuilding BlocksThermal InsulationWallboard

CementsAcid-ProofChimneyFurnaceRefractorySpark PlugStove

CeramicsCement GroutsChemical GroutingCleaning CompoundsCoagulantCoatings

EnamelsRoofing GranulesWelding Rods

Concrete CleanersConcrete TreatmentCorrosion ControlCorrugated Board

Dairy CleanersDeflocculation of ClaysDehumidifiersDe-inking Paper

Detergent FormulationsDishwashingDrilling Fluids

Mud AdditiveSilicate Base MudsSynthetic Muds

Drum Washing

Earthwork ConstructionEgg Washing

Fiber DrumsFire-Resistant PaintFloor CleanersFly Ash Structural MaterialsFoil LaminatingFoundry

CoresHot TopsMolds

FritsFruit & Vegetable Peeling

Ground Water ControlCanals,Ponds,Waste LagoonsSewer SealingShaft Tunnel & Mine SealingWells,Caissons,Irrigation

Heavy-Duty CleaningHog Scalding

Laminating Metal FoilLaundry OperationsLeather ProcessingLiquid DetergentsLithographic Printing

Magnesium TrisilicateMetal CleaningMolded ArticlesMolecular Sieves

Oil ReclaimingOil Wells

Cementing Casing for Later RecoveryCorrosion ControlFormation CleaningFracture FluidsHeavy ShaleWater ExclusionWorkover Fluids

Ore Flotation

Paint & Rubber FillersPaint RemoversPaintsPaper CoatingPaper Tube WindingPelletizing MineralsPigmentsPolishing Wheel CementPortland CementPoultry Processing

Radiator CompoundsRelease AgentRust Removers

Sealing ContainersSealing Metal CastingsSecondary Oil RecoverySilica Gel

AerogelHydrogelXerogel

Soap ConditionersSoap-MakingSoil SolidificationSolid FiberboardSource for Silica SolsSpace Vehicle PaintSteam Cleaning Synthetic CatalystsSynthetic Detergents

Textile ProcessingTimed FertilizersTire CleanersTitanium Dioxide

Ultramarine

Vegetable Oil Refining

Washing LocomotivesWater Clarif icationWater TreatmentWire Drawing

Zeolite (Synthetic)

Adhesives and Cements

Liquid sodium silicates of suitable con-centration, usually in the weight ratiorange of 2.8 to 3.3 are widely used asadhesives in making fiber drums,papertubes,and miscellaneous materials.Sodium silicate is an excellent adhesivefor sealing fiberboard boxes because itsets quickly and firmly holds the flapstogether. The advantages of solublesilicate adhesive include the easy wet-ting of the surfaces to be joined, con-trolled penetration, suitable viscosity,good setting characteristics,and highstrength.

Sodium silicates are especially valu-able as adhesives because they canchange from a liquid to a semi-solidcondition upon the loss of a smallamount of water. This property resultsin the adhesive taking a quick, initialset - so important in the modern, high-speed machine manufacture of paperproducts.

Sodium silicate solutions of widelyvarying ratios are used for makingmany kinds of cement,including typesfor acid-proof construction,refractoryuses,and binding thermal insulatingmaterials. Cements made with sodiumsilicates are used for lining and layingrefractory units,preparing foundrymolds and cores,laying brick in sulfitedigesters for chemical wood pulps,andconstruction of acid-proof masonry.Cements for stoves,chimneys, fur-naces,coke ovens,spark plugs,and forbinding metal to glass and porcelainare often made using sodium silicates.

There are a number of outstandingadvantages of sodium silicates asbinders in the cement mixtures. Theseinclude resistance of the set cements toacid, to high temperature, and to water.Silicate cements may be set by thereaction of an added substance, causingthe formation of a silica gel or heavymetal silicate.

Other advantages of sodium silicates asbinders in cements are ease of applica-tion, low costs,and a strong bondingaction for many types of surfaces.

Pulp & Paper

Sodium silicates are used for de-inking,sizing, coating, and bleaching of recy-cled paper products in the pulp andpaper industry.

Sodium silicates have long been thestabilizer of choice for hydrogen perox-ide bleaching of cellulose. Hydrogenperoxide is an efficient and economicalbleaching agent when properly stabi-lized against heavy metal ions,enzymes and other process impurities.Optimal efficiency is achieved when thesolution is correctly buffered in the alka-line pH range. Sodium silicates areeffective and economical stabilizers and bufferingagents.

Sodium silicates and hydrogen peroxide are used together for thebleaching of cellulose, in the

following industries:

The Pulp & Paper Industry, where they brighten both soft and hardwoodpulps. They are used mainly with mechanical ground-wood pulps to upgrade newsprint stock, and with whiter goods such as toweling,napkins,magazine stock and better quality printing papers.

The Waste Paper or Paper Recycling Industry, where sodium silicates aid in repulping and de-inking operations. Silicates stabilize and buffer peroxide bleaching steps to provide a whiter recycled pulp.

OxyChem’s Grade 40 liquid sodium silicate is the preferred silicate for wood pulp bleaching operations. Grade 50 is also used in pulp bleach liquor and can achievecost savings in some situations.

As efforts to recycle paper increase,waste paper has become a key rawmaterial. Approximately 25% of thefiber used by paper and board millsnow comes from waste paper, and thisamount continues to increase. Ten tofifteen percent of waste paper is de-inked and bleached to make whitergrades of paper. The balance is used inpaper board products where brightness and cleanliness are not asimportant.

The de-inking process solubilizesand removes nonfibrous materials,suchas inks,from the fiber stock. This isusually accomplished by:

•Mechanical pulping of paper to be recycled.

•Alkaline cook solution to suspend nonfibrous materials (primarily inks).

•Washing and/or flotation to separatede-inked fibers from impurities.

Sodium silicates perform many of theroles in the waste paper reclaimingprocess. They act as buffering agents,regulating the intensity of alkaline

5

Principle Uses of Sodium Silicates

6

Principle Uses of Sodium Silicates

conditions. They also prevent unnecessary degradation of the fiberstock during the alkaline cook Silicatesalso act as dispersing agents,suspendinginks and other undesirable materials,preventing their redeposition onto the fiber.

Detergents & Soaps

Many detergent operations are performed using both the liquid and dry granular forms of sodium silicates.Such operations range from metal clean-ing, textile processing, laundering andde-inking paper, to washing dishes,dairyequipment,bottles,floors,and locomo-tives. For instance, in the textile indus-try, sodium silicates are used withbleaches,soaps,wetting agents,synthetic detergents and other alkalies inoperations such as cleaning and finishing, kier boiling, wool scouring,bleaching and degumming.

A large amount of research has beendone on the principles of cleaning anddetergent processes,helping to establish thevalue of sodium silicates as detergents.

Sodium silicates possess such fundamental properties as low interfacial tension of solutions againstvarious components of dirt, good emulsifying and suspending powers,reserve alkalinity for neutralizing orsaponifying soil materials,and highbuffering power. Buffering enablesdetergent solutions to maintain approxi-mately the same pH value on dilution,oruntil most of the alkalinity has been neu-tralized by acidic materials.

Cleaning with alkaline solutions is theoldest form of commercial metal clean-ing and still the most widely used. Thealkaline, crystalline metasilicates,suchas UNIFLO 26and S-25,are widely usedfor metal cleaning either separately or ascomponents in cleaning formulas. The granular, free-flowing

property of UNIFLO makes it especiallysuitable for dry mixing with other clean-ing agents such as various phosphates,soda ash,caustic soda,and wetting agents. Soak-tank,spray,and electrolytic types of cleaning are carried out using alkaline solutions.Generally, sodium silicates in the metato ortho ratio range are important ingredients in these solutions.Temperatures in alkaline cleaning baths usually vary from around 1600 Ffor the spray-type process to just underthe boiling point for the soak-type andelectrolytic processes.

For well over a century, both liquidsilicates and metasilicates have beenadded to soaps as builders. Liquid silicate of a weight ratio around 3.3 is used in the order of 1% (anhydrousbasis) in bar and toilet soaps to prevent rancidity.

In the commercial and the self-service types of laundries,metasilicatesare used as soap builders. The silicate isused either alone or in combination withother alkalies,and the detergent action isconsiderably enhanced over that of soapalone.

The use of synthetic detergents hasgrown very rapidly. These detergentswere first used alone and later, in combination with phosphates and otherbuilders as the detergent properties weregreatly improved. However, a seriousweakness developed with the introduc-tion of these detergents for householdwashing tasks. It was found that the syn-thetic detergent compositionswere corro-sive to aluminum,zinc, and certain metalalloys used in domestic washers. Therewas also attack on porcelain enamel andoverglaze fine china decorations. Theincorporation of sodium silicate in thecompositions brought these corrosionand alkali attack problems under control.

While many new detergent productshave since been introduced, sodium silicates still perform the same functions in these new products.

Gels, Catalysts andZeolites

Silica gels may be prepared by treatingsodium silicate solutions with acids,washing the precipitated silicic acid toremove soluble salts,drying, and reducingthe resultant product to suitable particlesize range. Siliceous ratio silicates are generally used for makingsilica gels. The end product,a granularglassy material, has an immense internal pore area,giving it the capacityto absorb large quantities of moisture aswell as other substances. This propertymakes gels useful as dehumidifyingagents for air and other gases,and as fil -tering agents to clarify juices and beers.Specially prepared silica gels are usedfor making thermal insulation materials.

7

Principle Uses of Sodium Silicates

Closely related to silica gels are theamorphous silica powders which areused as additives to rubber products toprovide abrasion and wear resistance.Other uses for these silica products arefor thickening agents in inks,plasticsand varnishes,suspending agents inpaints,as well as anti-caking additivesin various compounds,such as dustingpowders and insecticides.

Sodium silicate solutions react withsolutions of many soluble salts to formcomplex gelatinous precipitates. Forinstance, aluminum salts react withsodium silicate solutions to form sodi-um-aluminum silicate gels which canbe processed to make base-exchangematerials particularly suitable for water softening.

Many combinations of silica gelwith other substances are used in mak-ing catalyst materials. One of the mostwidely used of these is the silica-alumina type of catalyst,whichcontains alumina intimately associatedwith the silica gel. With careful andprecise processing, the dried silica-alu-mina catalyst is used in various opera-tions in the petroleum industry, such asthe production of high octane gasoline.Silica gels,with quantities of variouscompounds co-precipitated or depositedafter the siliceous material has solidi-fied, have been used to increase cat-alytic activity in a wide range of reac-tions such as oxidation of organic com-pounds,cracking petroleum hydrocar-bons,and oxidation of sulfur dioxide to sulfur tri-oxide.

Similar in some aspects to silica gelcatalysts are the molecular sieve com-pounds formed by the reaction of sodi-um silicate with various salts,such assodium aluminate.

The molecular sieve compounds arecrystalline in structure and have con-trolled internal pore sizes. This givesthe sieve compounds the remarkableproperty of being able to separate mix-

tures of different sized molecules.Upon passage through a molecularsieve, a particular sized molecule in amixture is retained in and on the pores,thus effecting a separation or screening action.

Foundry Another application of the gel-formingproperties of sodium silicate is in thefoundry industry. Mixtures of sand andsilicate for making both molds andcores in the foundry are given an initialset by forcing CO2 gas under pressurethrough compacted forms. The initialhardening of the silicate-sand mix inthe CO2 process is caused by a chemical reactionbetween the carbon dioxide gas andsodium silicate. The alkali of the latter is partially neutralized, formingan gelatinous silicic acid which bindsthe sand particles together in a stiffmass. Later, as the mix loses moisture,further bond strength is provided.Molds and cores made by this processcan be used immediately and need notbe dried or baked, as required in thecase of oil or resin bonded forms.Sodium silicate solutions in the weightratio range from 3.22 to 2.00 are gener-ally recommended for foundry use.Often certain organic materials,such assugars,are first mixed in the silicate toimpart special properties.

Soil StabilizationThe gel-forming property of sodiumsilicate is used to advantage in soil sta-bilization. Sodium silicate solutions,along with reacting chemicals,havebeen used for the consolidation ofporous soil structures for many years.Soils are solidified and stabilized toincrease their load-bearing capacity, toarrest settlement and lateral movement of foundations,and to control the flow of water inearthwork engineering projects such asdams,mines,tunnels,and

excavations.

The stabilization of porous soils by sodium silicate is brought about byan induced gel formation of a silicatesolution after introduction into the soil.Gelling of the silicate solution resultsin a modified soil structure of increased strength and reduced permeability. The gelling may bebrought about by either immediate or slow reaction.

In the first case, or immediate reaction,separate solutions of untreated sodium silicate and of areacting material are alternately introduced into the same soil formation. Upon contact of the two solutions in the subsurface soil,immediate gelling occurs.

Principle Uses of Sodium Silicates

In the second case, which is the pre-ferred method, reacting chemicals aremixed with the silicate solution,caus-ing a delayed self-hardening action.The delayed gelling solution,or chemi-cal grout,solidifies at a pre-determinedtime after being pumped into a pervioussoil formation. This grout solution maybe varied as to concentration, viscosity,and gel time to meet various mixingand injection requirements. Hardeningof the grout solution in the soil is uni-form and complete. This method ofsingle injection has the additionaladvantage of using only one final solu-tion.

Silica Sols and WaterTreatment

Silica sols of colloidal silica may beprepared in several different ways.Methods of preparation include dialysis,electrodialysis,neutralization of a sodi-um silicate solution by an acid or acid substance, peptizing a silicahydrogel, and passage of a sodium silicate solution through an ionexchanger for sodium removal.

The theory of formation of colloidalsilica in the activated form as used inwater treatment is generally regarded tobe the growth of silica particles fromlow molecular weight silicic acid.Freshly liberated from the sodiumsilicatesolution by neutralization, these acidspolymerize, increasing in molecularsize, and form micelles of polymerizedsilicic acid with a strong negativecharge. After a controlled aging period,the silica sol is diluted to prevent fur-ther polymerization and to stabilize fora relatively short time the activated sili-ca.

Activated silica sols are used inwater purif ication as coagulant aids,flocculating impurities with aluminumand iron salts. In lime softening ofwater, activated silica acts as a primarycoagulant. Activated silica is used inthe treatment of both raw and wastewaters.

Corrosion of iron in water systems maybe controlled by the addition of smallamounts of sodium silicate, usually ofsiliceous ratio, which deposits a thinprotective film of silica on the metal.In alkaline cleaning operations,thepresence of sodium silicate in the deter-gent solution inhibits attack by the alka-li on aluminum and will greatly retardthe attack on zinc. Again,a protectivefilm on the metals derived from thesodium silicate inhibits the action of thealkaline solution.

CoatingsSodium silicate solutions,either unaltered or suitably modified, are usedin making various paints and coatings.Upon losing small amounts of water,thin layers of liquid silicates firstbecame tacky and then change to hardfilms.

Considerable loss of water occurs at ordinary room temperatures,but torender the film more water-resistant,elevated temperatures are necessary fordrying.

If heat is to be used in the drying oper-ation, it is important that silicate filmsand coatings not be exposed to an ini-tial temperature that is too high.

The temperature should first be slow-ly raised to around 210oF and held thereuntil the majority of the water isremoved. Then,the temperaturemay beincreased to the final level desired, suchas in a 300-700oF range. Sudden heat-ing of the wet film to a high tempera-ture is not desirable. Such treatment inmany instances would cause steam for-mation, resultingin blistering and lossof integrity in the dried film. Infra-redheat is suitable for drying silicate films.

Sodium silicates used in coating andpaint formulations vary in ratio fromabout 2.0 to 3.3. The alkaline ratio sili-cates dry somewhat more slowly than

the siliceous liquids. The alkaline ratiosolutions dry to form films that areslightly more flexible than those ofsiliceous ratios.

If high temperatures are not practical,the water resistance of a sodium silicatefilm may be enhanced by reaction withan acid or certain salts,such as boricacid, phosphoric acid, sodium silicoflu-oride, and aluminum phosphate. Suchmaterials may be incorporated in thepaint formula or applied as a solutioninthe form of a second coating or curing treatment.

Two other well-established applications of sodium silicate coatings are for welding rods and roof-ing granules.

8

9

Specific Applications for OxyChem Silicates

Use -Application

GradeSilicate Proper ties Advantages

Abrasive wheels

Acid-proofcement

Adhesive formulations

Briquetting glassbatch and coal

Coating formulations

Coating roofinggranules

Corrosion control in water lines

Deflocculatingclays

De-inking paper

Drilling muds

Engine coolants

Fiber drums

Foundry moldsand cores

Furnace andstove cements

Hardeningconcrete

Hot tops for steelingot molds

Kier boiling textiles

40

40, 42

40, 42, 47

40, 42, 47

40, 47

40, 42, 47, 50

40, 42, 50

40, 42, 47, 50, 52

All grades

40, 42, 50, 52

40, 40 Clear

42

49 FG, 47, 50, 52

50, 52

40, 42

40, 49 FG, 52

JW-25, 40, 42,JW Clear, 30 Clear

Binding

Acid resistance

Binder

Binding

Film formation

Film formation

Film formation

Dispersingaction

DeflocculatingactionColloidal

Corrosioninhibition

Adhesive - Fast set

Binding

Binding

Chemical

Binder

Detergent

Economical binder

Economical - High performance

Strong bondsEconomical

Reduce dusting

Low cost -Fire resistant

Fireproof -Water resistancePigment binder

Reduces rust and lead

More fluid -Power reduction in brickmaking

Whiter pulp

Stabilizing wellbore

Protects radiatorsand water pumps

High strength

Fast set

Plastic - Heat resistance

Dust-proofs _Longer life

Economical binder

Whiter cloth _

Better dyeing

10

Specific Applications for OxyChem Silicates

Use -Application

GradeSilicate Proper ties Advantages

Laminatingpaper and metalfoil

Leak sealingcompounds

Manufacture of gels, catalysts, andmolecular sieves

Manufacture of soaps, detergents andindustrial cleaners

Manufacture oftitanium dioxide

Manufacture ofultramarine

Metal cleaning

Ore flotation

Paper beatersizing

Paper products

Pelletizingminerals

Pulp bleaching

Slurry thinner

Soil stabilization

40, 45, 47, 49 FG

42, 47, 50

40, 42,

40, 42, 49 FG, 50,52, Anhydrous

MetasilicateUNIFLO®

40, 42

40, 42,

AnhydrousMetasilicateUNIFLO®

40, 42, 47, 50, 52UNIFLO®

40, 42

40, 42

40, 42

40, 40 Clear, 50

40

40

Adhesive-Fast set

Film forming

Chemical

Wetting andemulsifyingaction

Coats particles

Coats particles

Wetting andemulsifyingaction

Deflocculatingaction

Formation ofprecipitates

Adhesive-Fast set

Binding

Buffering andsequesteringagent

Transport andhandling

Chemical

High speed operation _

Thin film application

Economical _

Rust inhibitor

Convenientsilica source

Metal protection _

Increased detergency

Acid resistanceReduces chalking

Increased acidresistance of pigment

Increased detergency

Improved separation

Smooth, hardpaper surface

High strengthboard-Ready to useadhesiveImparts some fireresistance

Fast set- Strong bond

Conservesoxygen

Improved transportationeconomics

Increased loadbearing-preventsfoundation settling- preventscave-in during con-struction

11

Principle Grades of OxyChem Sodium Silicates

OxyChem Solid Sodium Silicate Glass Briquettes

Anhydrous GlassPhysical Form _

3.22 ratio

Weight ratio _ typical

Weight per cu. ft._briquettes_approx.

.

A clear glass in briquette or crushedform

Na

2 O : 3.22 SiO2

85 - 90 pounds

Grade %Na2O

%SiO2

%H2O

Weight RatioSiO2/Na2O

Gravityo Be

Viscosity CPS

40

40 Clear

42

JW Clear

JW-25

47

49 FG

52

50

WD-43

30 Clear

20 Clear

9.1

9.1

9.3

10.6

10.6

11.2

12.4

13.9

14.7

13.3

10.6

8.9

29.3

29.3

30.0

26.9

26.9

31.8

32.0

33.4

29.4

23.9

27.0

28.9

61.6

61.6

60.7

62.5

62.5

57.0

55.6

52.7

55.9

62.8

62.4

62.8

3.22

3.22

3.22

2.54

2.54

2.84

2.58

2.40

2.00

1.80

2.55

3.25

41.5

41.5

42.5

42.0

42.0

47.0

49.0

52.0

50.0

43.8

42.3

41.00.4

200

200

400

65

65

650

600

1800

340

60

65

175

Gravity and Viscosity Values at 200 C In addition to the above regular grades,OxyChem makesspecial sodium silicates of different compositions to meetcustomer specifications.

OxyChem Sodium Metasilicates

UNIFLO®

Sodium MetasilicatePentah ydratePhysical Form A white,

free-flowinggranular product

Molecular ratio and hydrate-approx. Na2O-SiO2-5H2O

pH values (3) at room temperatures

0.1% solution 11.51.0% solution 12.45.0% solution 13.0

Total Na2O - typical 29.2%Solids content - typical 58.2%Melting point 72.2OC

Containers NetWeight (Approx.)

Multiwall bags 50 lb.

100 lb. 25 Kg bags

Bulk bags (Super sacks)Bulk Rail CarsBulk Trucks

UsesDairy cleaningLaundry operations Detergent formulationsMetal cleaningDishwashing compounds Paper mill operationsCar washIndustrial cleanersConcrete cleaning

S-25 Anh ydr ous Sodium MetasilicatePhysical Form A white,

free-flowinggranular product

Molecular ratio - approx. Na2O - SiO2

pH values (3) at room temperatures

0.1% solution 11.81.0% solution 12.75.0% solution 13.2

Total Na2O - typical 51.0%Solids content - typical 99.5%

Melting point 1089oC

Containers Net Weight(Approx.)

Multiwall bags 50 lbs.

100 lbs.

25 Kg. bags

Bulk bags (Super sacks)Bulk Rail CarsBulk Trucks

UsesDairy cleaningFloor cleaningDetergent formulationsLaundry operationsDishwashing compounds Metal cleaningIndustrial cleanersSoil stabilization

12

13

Liquid SilicatesSodium silicates are non-flammable,non-explosive, and non-toxic. Theyare, however, alkaline materials andpose hazards to the skin and eyes. Thephysiological effects of contact varywith the alkalinity of the silicateinvolved, and range from causing irrita-tion to causing chemical burns.

While the liquid grades of sodiumsilicate of greater than 1.6 weight ratioare not strongly alkaline, they shouldbe handled with care. If there is anyrisk of silicate solution splashing in theeyes,goggles should be worn. It isalso recommended that appropriateprotective clothing and gloves be wornto prevent silicate solutions from com-ing into contact with the skin.Additionally, the use of oil-based coldcream or petroleum jelly on skin areasthat could possibly come in contactwith the silicate would also be benefi-cial. Under no circumstances shouldliquid sodium silicates be taken inter-nally.

Prior to using any liquid silicate,carefully read and comprehend thematerial safety data sheet specific forthe grade of silicate being used.

MetasilicatesThe granular metasilicates are alsonon-flammable and non-explosive but are highly alkaline. The compoundsthemselves,as well as water solutionsof the metasilicates,may cause chemicalburns to the skin and eyes. Appropriateeye protection,as well as protectiveclothing and gloves,must be wornwhen handling sodium metasilicates.

Consult the specific material safetydata sheet for detailed handling instruc-tions and recommended first-aidproce-dures prior to use.

Safety Procedures in Handling Sodium Silicates

Storage and Handling

The various grades of liquid sodiumsilicates are supplied in quantities vary-ing up to 16,000 gallon lots. The smallest quantity normally shippedis in 55 gallon steel drums. Largershipments are made in tank trucks andrailroad tank cars,by pipelines,and inlarge, synthetic rubber, collapsible containers.

Tank truck shipments of silicates inorder of 3,000-4,000 gallon quantitiesare usually made for deliveries to customers requiring less than tank carquantities. Larger shipments are ordinarily made in 16,000 gallon and10,000 gallon railroad tank cars.

In those instances where a customer’s plant is located near a sodium silicate plant and the silicate requirements are large,it is sometimes economical to construct a pipeline between the two plants and make silicate deliveries through the line.

Unloading Tank Cars

Sodium silicate tank cars may be unloadedby gravity flow (if the top of the receivingtank is lower in level than the outlet of thetank car),by pumping, or by air pressure.Arrangement of the unloading mechanismvaries somewhat with different tank cars.

Figure 1gives a sectional sketch of atank car showing one arrangement of theunloading mechanism. The outlet (9) onthe tank car is a special 4 inch fittingwhich is usually reduced to a 2 or 3 inchsize for capping or plugging. In any case,the outlet line of the tank car should beconnected to a 3 inch line leading to thestorage tank. Some cars are equipped witha gate valve and plug, instead of a valvecap assembly with plug as shown in theillustration. The cars are usually equippedwith steam coils for warming or thawingthe sodium silicate in cold weather.

Referring to Figure 1,instructions arenoted below for unloading sodium silicate from tank cars.

1.Set handbrake and block wheels aftercar is properly spotted. Caution signsshould be placed at both ends of the carbeing unloaded to warn persons,as well asswitching crews,that the tank car is con-nected. Derail attachments are sometimes advised for the open end of thesiding. Goggles or face masks should be worn to guard against eye injury.

2.Remove the dome cover (1),and try outthe foot valve (6) to make certain it is inthe closed position.

3.Remove valve cap assembly (10) at thebottom of the outlet (9),and attach tankcar angle connection and hose or pipe tostorage tank. If it is convenient to use the2 inch opening, remove the 2 inch plugand bush to 3 inch for connection to therubber hose or pipe.

4.Return to the dome and open the footvalve (6) by turning the valve rod handle(3). Leave dome cover off unless unload-ing with air pressure. If unloading with apump,start the pump after the foot valve isopened. With gravity flow unloading, thesilicate will start to flow when the footvalve is opened.

5. If air is employed for unloading, use thefollowing procedure. After opening the

foot valve, replace the dome cover using agasket and tighten. Then attach an airpressure line at the connection provided on the dome cover. When air is turned on the silicate will start to flowfrom the car. Care should be taken not to use air pressures greater than about 25 psig since the safety valve (2) is set torelease at 25 to 30 psig. For safety, thereshould be installed in the air line to thedome a gauge and a safety valve set torelease at 25 psig.

6. If necessary to heat the silicate withsteam,first loosen dome cover. Thenremove the caps or plugs from the steamcoil inlet (8) and outlet (7) connections,and attach a steam line to the inlet connec-tion (8). Introduce steam slowly into theline until the pipes are heated, and steamand condensate emerge from the coil outlet (7). Steam may then be somewhat increased, but care should be exercised to prevent rupture of the steamheater pipes. Since prolonged use ofsteam is not desirable, turn off the steamand unload as soon as the silicate is warmenough to flow readily. Low pressuresteam at 5-15 psig should preferably beused to prevent possible deposits on thecoils.

In any case, turn the steam off before thesilicate has dropped below the level of theheating coils inside the car. After the car isunloaded, any condensate remaining in thecoils should be blown out using com-pressed air. This is to prevent possible freezing and bursting of

the pipes. The caps or plugs should thenbe replaced on the steam inlet and outletconnections.

7.After all the silicate has been unloadedfrom the tank car, close the foot valve (6)by turning the valve rod handle (3),andremove the connecting ribbed rubber hoseand angled fittings. Screw on the pipe plugor cap to the car outlet connection.Then,add about 50 gallons of water to the car toprevent hardening of the silicate around the foot valve, and replacethe dome cover (1). Any other connectionsthat have been made should be disconnected.

8.After the car is empty, precautionsshould be taken to insure that the unloadingline is drained or thoroughly flushed.Otherwise, the silicate may harden orfreeze in the line. It is good practice tomake the flexible connection on theunloading line removable so it can be disconnected and soaked in water to prevent hardening of silicate in the threadsor joints. If unloading is by gravity, the unloading line may be clearedby blowing with air or steam from the tankcar end of the line. If a pump is used, theline should be pumped dry and the valveclosed on the pump inlet. Then,the lineshould be blown back from this point. Thepump is usually left full of silicate. Thetank car end of the line should then becapped to minimize drying of any remaining silicate.

14

15

Tank truck shipments of liquid sodiumsilicate are made in quantities ofapproximately 3,500 gallons.

The unloading of a tank truck is han-dled by the truck driver using a pumpor air compressor mounted on thetruck. Normally, 10 and 20 footlengths of heavy rubber hose are car-ried on the truck for connecting to theline provided by the customer andleading to the storage facility, or tank.

The unloading line to the storage tankshould be 3 inch steel pipe and locatedinside to the extent possible to preventfreezing. The connecting end shouldbe threaded and capped to prevent thesetting up and hardening of liquid sili-cate. A plug type valve should be inthis line close to the capped end.

Tank Trucks

Steel Drums

Drum shipments of liquid sodium silicate are made in 55 gallon non-returnable steel drums.

Air pressure should never be used onsilicate drums in emptying them. Thedrums are not built as pressure vessels,and could rupture under pressure causing a serious accident.

Shipments of sodium silicate indrums require an unloading dock formoving the drums in and out of themotor truck or railroad boxcar. Formoving, handling, and emptying drumsof silicate in the plant,use is ordinarilymade of such equipment as drum handtrucks, fork lift trucks,hoists,and drumcradles. Drum cradles are useful in handling and hold-ing drums for dispensing small quanti-ties of silicate.

In using a drum cradle for partialwithdrawals of silicate, the drumshould first be upended with the endhaving a 3/4 inch plug on top. Theplug is removed, and replaced with a3/4 inch gate valve drum spigot. Thedrum is then placed in a horizontalposition on the drum cradle with the 2 inch plug on top. As silicate is with-drawn, the 2 inch plug should be slight-ly opened to allow air to enter thedrum. After finishing a withdrawal ofsilicate, this plug should be screweddown to close the opening.

Drums should be stored in a dry, andin winter a reasonably warm, ware-house. If allowed to become coldenough to freeze, which occurs a little below 32OF, liquid grades ofsodium silicate, upon thawing,separate into layers of different

composition. To restore to the originaluniform composition,a thorough mixing is required which is difficult toaccomplish in drums. Therefore, toavoid a mixing operation, it is recom-mended that the silicate not be allowedto freeze. Furthermore, if the silicate iskept at ordinary room temperatures emp-tying from the drum is more easilyaccomplished by avoiding the higher vis-cosities due to lower temperatures. Onthe other hand, drums of silicates shouldnot be stored in places where the temper-ature is extremely high such as next to afurnace or heater. In general, tempera-tures under 90OF are desirable since pro-longed storage at higher temperatures may cause gradual thermal decomposition.

16

Storage

The general rule for storage capacity is1.5 times the normal shipment volume.Tanks may be constructed of 1/4”mildsteel but 3/8” gauge is preferred. Plastictanks made from alkali resistant polyeth-ylene or polypropylene may also be used.Silicate storage tanks should be coveredand provided with a manhole for inspection. Storage tanksshould also be provided with a vent andinlet and outlet lines. If tank car shipments are to be received, the storage tank should preferably have acapacity of not less than about 20,000gallons.

Location of storage tanks inside a heat-ed building is desirable to minimize coldweather troubles. Outside storage tanksshould be insulated (1 1/2” thick insula-tion is usually adequate) and provided with heating coils in most areas.External heating coils are recommended, since internal heating,except of the mildest type, probably will result in “baking” the silicate on the heating unit. Furthermore, internalheating may cause undue concentrationof the silicate solution,and the formationof an excessivequantity of sludge or “bot-toms” in the tank.

Long storage or storage at elevatedtemperatures should be avoided.

Foreign materials of all types should bekept out of silicate storage tanks,andinspection made at regular intervals tonote any accumulation of sediment onthe bottom of the tanks. Formation ofsediment,or “bottoms,” should becleaned from tanks as necessary.

Pumps, Valves and Piping

For handling the various grades of liquid sodium silicate, rotary or centrifugal type pumps have been found satisfactory depending upon the job to be performed. Flooded suction is required for centrifugal pumps,but such pumps normally require lessmaintenance since the packing gland is not subjected to full dis-charge pressure. Rotary pumps are used for services requiring positiveaction,and are self-priming. All ir onconstruction is satisfactory for silicatepumps,and standard steel pipe meets the

usual piping requirements. For most silicate installations,rubberdiaphragm or plug type valves are satisfactory. Gate valves are often used, but globe valves are generally to be avoided. The use of brass,bronze, copper, or aluminum on wetted parts should be avoided.

A special OxyChem Technical Bulletinon storing and handling liquid sodiumsilicates is available for those desiringmore detailed information.

Handling Sodium Metasilicates

Bulk truck shipments have been foundpractical for UNIFLO® sodium metasilicatepentahydrate, and anhydrous sodiummetasilicate. In particular, this is truewhere the distances involved are not greatand the consumption is not large enoughto justify rail delivery. Through bulk han-dling sodium metasilicates,a savings canbe realized in raw material costs and intra-plant handling.

A tank-type trailer is available for this ser-vice and is equipped with a build-onunloading system which pneumaticallyunloads the metasilicate into the storagebin. The unloading operation is carriedout by the truck driver, thus making acomplete delivery.

In the bulk storage and handling ofsodium metasilicates,the following pre-cautions should be observed:

1. Avoid moisture pickup in the storage bin with a desiccator breather.

2. Schedule shipments of material toavoid prolonged periods of storage.

3. The discharge opening of the storage bin should have a slope of atleast 60 degrees.

17

Handling Sodium Metasilicates cont’d

EquipmentThere is shown in Figures 2 and 3 adrawing illustrating a typical storagefacility for UNIFLO® sodium metasili-cate pentahydrate. A description of theequipment required follows:

1. Unloading line For receiving material from the self-

unloading truck, a transmission linemade with 4”standard pipe is required.

An adapter, OPW Kamlok No. 633A,is required on the 4”line to make theflexible hose connection to the trailer.A cap is needed on the open pipe tokeep the bin airtight and free of mois-ture.

To allow for a 5’radius bend in theflexible hose, the fixed transmissionline inlet should be 5’above groundlevel.

2. Storage binA 9’ diameter cylindrical, 60O cone

bottom bin with a capacity of about1200 cubic feet is suggested. This sizebin will hold approximately 30 tons ofUNIFLO® sodium metasilicate pen-

tahydrate. Prefabricated bins,suitable for metasilicate storage, aremanufactured by several companies.Generally, these bins afford consider-able savings over the custom-builtinstallations.

An unloading auger can be purchasedwith the bin. The standard 6” augerwill give a discharge rate of about 750cubic feet per hour.

3. Vent pipingAn 8” vent pipe connection from the

dust filter and desiccator is required.Slide gates should be provided toinsure having the vent open to the bagfilter during unloading.

4. Bag filterSince less volume of air is used in

this system than in a conventionalpneumatic system,the air separation isrelatively simple. A bag filter over the8” air outlet is all that will be required.We suggest using a resin-treatedDacron* cloth for the bag. The clothstyle #702-50 is used successfully inself-unloading truck installations. Thiscloth has a permeability rating of 20CFM per square foot at the 15 psi oper-

ating pressure. The bag is 4’in diame-ter and 6’long, or a total cloth area of75 sq. ft. This allows for more thanthree times the volume of air to bevented from the tank.75 sq. ft. x 20 CFM/sq. ft. = 1500 CFMcapacity 1500 CFM capacity - 450 CFM(truck compressor rating) = 3.3

* Reg. T.M. of E.I. du Pont de Nemours

5. DesiccatorTo avoid moisture laden air entering

the storage bin,a desiccator is recom-mended for the bin vent. The desicca-tor will contain a desiccant such as cal-cium sulfate, calcium chloride,silica gel, or a prepared mixture.

Changes in atmospheric temperatureand pressure will cause some passageof air in and out of the bin. However,most air will enter as material is beingevacuated. The desiccator size is deter-mined then by the flow rate from thebin auger. A 6” auger, for example,will have a flow rate of 750 cubic feetper hour. The desiccator should besized to handle that volume of air.

Technical Data

This section presents tables and charts giving chemical and physical data on sodium silicates.

Viscosity Change with Temperature - There is a rather large change in viscosity val-ues with change in temperature for the relatively viscous sodium silicate solutions.Chart 1,gives curves showing the change inviscosity with temperature change for the mostcommon grades of OxyChem sodium silicate.

Table 1 gives pH values of commercial con-centrations of selected OxyChem grades of liq-uid sodium silicate.

Gravity Correction for Temperature is shownin Table 2. The standard temperature used formeasuring gravity and viscosity values of sodium silicate solutions is 20oC.However, it is sometimes desired to convertgravity figures obtained at temperatures otherthan 20oC to approximate values at 20oC.

Table 3 shows the relationship betweenSpecific Gravity and Degrees Baumé,as wellas the lbs. per gallon equivalents.

Solids Content - Chart 2,gives the solids con-tent for different Baumé values at 20oC of sodium silicate solutions of the principalweight ratios that are made by OxyChem.Gravity Viscosity Relationships - Chart 3,

gives the gravity-viscosity relationship for theprincipal ratios of OxyChem liquid sodium sil-icates. Viscosity values were obtained using aStormer viscometer, an instrument commonlyemployed in the soluble silicate industry. Theunit of Stormer seconds used in Chart 3 has aconversion factor to absolute viscosity unitsover an approximate range of 80 to 950 cen-tipoises (equivalent to 29 to 345 Stormer sec-onds) as follows:

Stormer seconds x 2.75 = centipoises

The Stormer seconds unit as defined, whilean arbitrary one, is standard in OxyChem sodi-um silicate plants and for this reason is includ-ed along with centipoise values in this chart.In using Chart 3,viscosity values outside the range noted should be consideredonly approximate. The composition of a liquid sodium silicate may be estimated fromthe gravity and viscosity values.

Example: A sodium silicate solution has agravity of 41.2O Baumé and viscosity of 65 Stormer seconds,both at 20OC. Estimate the composition.

Solution: Using Chart

3, it is seen that the gravity and viscosity values correspond to a 3.2 ratio. From Chart 2,a solids content of 38.0% is given for a 3.22 ratio sodium silicate of 41.2O Baumé. Then,

% Solids contentwt. ratio + 1

= % Na2O

Or, 38.04.22 = 9.0% Na2O, and

38.0 - 9.0 = 29.0% SiO2

Thus,the estimated composition of the sodium silicate is:

9.0% Na2O29.0% SiO262.0% H2O

18

2.84Ratio

2.84Ratio

The information that follows is intended todescribe the various analytical proceduresused for sodium silicates in general terms.If more specific details are needed, pleasecontact your nearest sales office.

A. The sodium oxide content of sodiumsilicate is determined by a chemical titration of a sample with standardhydrochloric acid topH 4.3 using either apH meter or a suitable indicator such asmethyl orange. The usual procedure is toaccurately weigh a 25 gram sample of thesilicate and dilute to 500 ml with deionized water. A 50 ml aliquot is thentitrated with 0.2 N HCI. For highly alkaline grades,a 15 gram sample is suggested.

Calculations:

% Na2O = ml HCIxNormality x 3.1sample weight

B. Viscosity

The viscosity of liquid sodium silicatesolutions may be determined by either aStormer or a Brookfield Viscometer. Theinstruments must be standardized againstBureau of Standard oils in the viscosityrange of the material being measured.OxyChem’s standard temperature forreporting viscosity data is at 68

oF.

Readings may be taken at other temperatures and extrapolated to 68

oF

by referring to Chart 1. Data may bereported as either Stormer Seconds orCentipoises.

The conversion factor we use for converting Stormer Seconds to Centipoisesis 2.75 (Stormer Seconds x 2.75 =Centipoises.) The single most importantfactor in obtaining satisfactory results,besides careful instrument calibration, is a precise determination of the temperature of the silicate solution.

The accuracy of the thermometer shouldbe within 0.3

oF. Digital thermometers

have proven to be more accurate thanglass-stem mercury thermometers.

Gravity Determination

The gravity of liquid sodium silicates isusually measured at 68

oF using a Baumé

hydrometer standardized against a Bureauof Standards certified hydrometer.Measurements may be taken at tempera-tures other than 68

oF and extrapolated to

68oF for reporting purposes by referring to

Table 2.

The relationship between degrees Bauméand Specific Gravity is:

Degrees Baumé = 145 - 145/ Specific Gravity

Specific Gravity = 145/ (145 - degrees Baumé)

Total Solids

The total solids of liquid silicates is theresidue remaining after careful ignition ofa small sample in a muffle furnace. Theprocedure consists of accurately weighinga 1 to 2 gram sample into a tared,previously fired, porcelain crucible andigniting to 1050

oC for one half hour.

A few drops of 30% hydrogen peroxideshould be added to prevent spattering.After cooling in a desiccator, reweigh thecrucible. The weight of the residue is the% solids and is reported to the nearest0.01%.

Silicon Dioxide

For all but the most critical situations,the SiO2 content may be calculated by subtracting the % sodium oxide from the % total solids as determined by the previously described procedures. For moreprecise purposes,a weighed sample

is diluted with deionized water and acidified with dilute hydrochloric acid. After evaporating to dryness on a hot plate,the resultant silica gel is rinsed free ofchlorides. The residue is ignited in a muf-fle furnace in a carefully weighed crucible.After cooling and weighing,the residue is calculated directly as SiO2.

Ratio

Sodium silicates are often described by theweight ratio of the silicon dioxide to thesodium oxide, with the sodium oxide asunity. It may be calculated directly bydividing the % SiO2 (determined fromeither one of the above described procedures) by the % Na2O that has been chemically determined. A morerapid, but still quite accurate, method con-sists of carefully measuring the gravity and viscosity at 68

oF. By

referring to Chart 3, the ratio of theSiO2/Na2O ratio can be determined.

Chart 2,shows the interrelationships of the ratio, gravity, and the solids contentfor the various liquid sodium silicates.

Methods of Analysis

21

Occidental Chemical CorporationOccidental Tower, 5005 LBJ FreewayP.O. Box 809050, Dallas, TX 75380-9050972/404-3800

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Basic ChemicalsSilicates

58-2211 / 97 2.5M