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  • Handbook K2CO3 1

    In 1986, two strong manufacturersin the chemical industry combinedin a joint venture to form theArmand Products Company theleading producer and marketer ofpotassium carbonate and potassiumbicarbonate in the world.

    From the Occidental ChemicalCorporation came the manufactur-ing capability for the production ofthe highest quality chemicals, withmarketing and technical serviceexpertise for product support.

    From the Church & Dwight Co.,Inc. came the sales and R&D func-tions to maintain the high level ofcustomer service that our customersrequire.

    As a market leader, the ArmandProducts Company provides thefacilities and manpower needed tomeet the requirements of our cus-tomers. Our two plants and fourreactors run in the continuousmode, assuring an uninterruptedsupply of potassium carbonate. Anadditional reactor is dedicated tothe production of potassium bicar-bonate. This manufacturing facilityis located in Muscle Shoals, AL.

    Armand Products Company hasfull integration with a dedicatedproduction source of potassiumhydroxide, the key raw material formaking potassium carbonate.Potassium bicarbonate is producedby further carbonation of potassiumcarbonate. The Tennessee ValleyAuthority (TVA), one of the largest

    electricity generators in the UnitedStates, supplies power to the MuscleShoals facility at a reasonably stablecost.

    Current capacity is 108,000 shorttons/year for potassium carbonateand 5,000 short tons/year for potas-sium bicarbonate. This placesArmand Products as the largestdomestic and international sourceof potassium carbonate, as well asthe only producer of potassiumbicarbonate in the U.S.

    In order to meet the require-ments of the many diverse applica-tions, each product is available inseveral different grades. Variouspackage forms are also available,ranging from bags to railcars.Smaller packages are availabledirectly from the plant or at manywarehouse and distribution pointsacross the country.

    Armand Products commitmentto quality and consistent perfor-mance is shown in its continuedgood standing as an ISO 9002 certi-fied and OSHA Star facility.

    Potassium Carbonate Handbook

    Background

  • Armand Products Company

    2 K2CO3 Handbook

    PageBackground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1l. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3ll. Markets and Uses of Potassium Carbonate . . . . . . . . . . . . . . . . . . . 4lll. Manufacturing Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6lV. Grades of Potassium Carbonate . . . . . . . . . . . . . . . . . . . . . . . . . . . 8V. Materials of Construction

    A. Anhydrous Potassium Carbonate . . . . . . . . . . . . . . . . . . . . . 9B. Liquid Potassium Carbonate . . . . . . . . . . . . . . . . . . . . . . . . 10

    Vl. Shipping Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Vll. Precautions in Handling Potassium Carbonate . . . . . . . . . . . . . . 13Vlll.Handling of Anhydrous Potassium Carbonate

    A. Bag, Drum and Bulk Handling . . . . . . . . . . . . . . . . . . . . . . 15B. Mechanical Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16C. Pneumatic Conveying . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18D. Bulk Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

    lX. Handling of Liquid Potassium CarbonateA. Shipping Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22B. Unloading Tank Cars

    Placement, Precautions and Cold Weather . . . . . . . . . . 22Unloading Through Bottom Valve . . . . . . . . . . . . . . . . . 24Top Unloading with Air Pressure . . . . . . . . . . . . . . . . . 26Preparing Car for Return . . . . . . . . . . . . . . . . . . . . . . . . 26

    C. Unloading from Tank TrucksMethods and Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . 27Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

    D. Dilution of Potassium Carbonate Solution . . . . . . . . . . . . . 30E. Dissolving Anhydrous Material . . . . . . . . . . . . . . . . . . . . . 31F. Solution Storage with Dry Bulk Delivery . . . . . . . . . . . . . . . 31

    X. Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33XI. Methods of Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

    All recommendations and suggestions appearing in this booklet concerningthe use of our products are based upon tests and data believed to be reliable.However, as the actual use of our products by others is beyond our control,no guarantee, expressed or implied, is made as to the effects of such use, orthe results to be obtained, whether or not any use of our products is made inaccordance with recommendations or suggestions contained in this hand-book or otherwise. Furthermore, information on the use of our products isnot to be construed as recommendation to use such products in the infringe-ment of any patent. These suggestions should not be confused either withstate, municipal, or insurance requirements, or with national safety codes.

    Table of Contents

  • Armand Products Company

    Handbook K2CO3 3

    Potassium carbonate is one of themost important inorganic com-pounds used in industry eventhough it is as old as recorded histo-ry. Potassium carbonate was leachedfrom ashes in Pompeii and mixedwith slaked lime for soapmaking.The increase in the use of this alkaliparalleled the growth of westerncivilization. So much wood wasconsumed in the production ofpotassium carbonate that the forestsof Europe were threatened. At thetime of the French Revolution,LeBlancs invention allowed sodiumcarbonate to be substituted on ageneral basis.

    The potassium carbonate thatwas recovered from ashes becamethe prime potassium compoundbefore 1870. During these earlytimes, potassium hydroxide (KOH,caustic potash) was made frompotassium carbonate by reactionwith calcium hydroxide. However,the recovery of potassium chloridein 1860 from rubbish salt in theStrassfurt, Germany salt mineschanged this methodology. Todaypotassium hydroxide is producedthrough the electrolysis of potassi-um chloride brine. Subsequently,the KOH is carbonated with carbondioxide to form potassium carbon-ate.

    K2CO3 is the chemists short-wayof representing potassium carbonateor PotCarb as it is commonly calledtoday. Although it is known by sev-eral other names, the chemical for-mula is the most definitive way toconfirm this compound. Some ofalternate nomenclature that may beused includes: PC, carbonate ofpotash, pearl ash and carbonic acid,dipotassium salt.

    In everyday chemical technolo-gy, the choice between potassiumand sodium carbonate is decided on

    the economics or some desiredphysical / chemical property. Theprincipal reasons to utilize potassi-um carbonate are:

    t source of potassium iont buffered alkalinityt greater solubility for potassi-

    um vs. sodium carbonatet potassium ion is more reactive

    than sodium iont replacement for sodium sensi-

    tive applicationst enhances fluxing properties of

    glasst depresses freeze point of

    water, allowing cold tempera-ture applications

    In the past, the use of a hydratedpotassium carbonate (16% water)was preferred to the more deliques-cent anhydrous form. Technologyhas since spurred improvements inseveral areas, thereby fostering theacceptance of the anhydrous granu-lar form of potassium carbonate.These improvements include thedevelopment of other PotCarbprocesses and enhancements in theareas of packaging, dry bulk han-dling and storage facilities.

    One commonly used methodproduces a calcined PotCarb thatrequires several additional process-ing steps after its liquid phase reac-tion between caustic potash andcarbon dioxide. The final step beinga heat treatment where the temper-ature is raised sufficiently to driveoff the water of crystallization. Twodifferent ion exchange methodseach employ a multi-step processthat requires several raw materialsand also yields several by-products.A more practical approach for sup-porting the use of anhydrous potas-sium carbonate is the developmentof the fluidized bed reactor. This

    l. Introduction

  • Armand Products Company

    4 K2CO3 Handbook

    process allows the direct, one-stepmanufacturing of an anhydrousmaterial that needs no furtherrefinement. Typically there is muchgreater customer demand for drymaterial, however, since PotCarb itis readily soluble, aqueous solutionsdo not present a challenge. ArmandProducts is well positioned to meetthe demands of todays customerswith its four state-of-the-art flu-idized bed reactors and its liquidPotCarb capabilities.

    The potassium carbonate market isdivided between the glass industryand other numerous applications.Product is shipped throughout theUnited States and into internationalregions.

    Video glass accounts for 44% ofpotassium carbonate usage, whilespecialty glass and ceramics use10%. The main reason that relative-ly expensive potassium carbonate isused in place of soda ash in glassapplications is that it is more com-patible with the required lead, bari-um and strontium oxides. Thesespecialty glasses possess theimproved properties of greater elec-trical resistivity, higher index ofrefraction, greater brilliance or lus-ter, lower softening point and awide temperature working range. Inaddition, potassium carbonateallows improved behavior of manycolorants in glass.

    Potassium carbonate has a widevariety of uses outside of the glassindustry. Major applications thataccount for 46% of the PotCarbproduced include but are not limit-ed to: potassium silicate, pharma-ceuticals, food, detergents andcleaners, photographic chemicals,agricultural, gas purification, rubberadditives, polymer catalysts, potassi-um bicarbonate, cement and tex-tiles.

    A more complete summary ofthe various uses of potassium car-bonate is given in the followingtable:

    Markets and Uses ofPotassium Carbonatell.

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    Armand Products Company

    Handbook K2CO3 5

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  • Armand Products Company

    6 K2CO3 Handbook

    Armand Products PotassiumCarbonate is manufactured in a flu-idized bed reactor at its productionfacility in Muscle Shoals, AL. Thisresults in a product that is anhy-drous, making it unnecessary toperform any further processing toeliminate hydrated water (calcin-ing). Armand Products PotassiumCarbonate (PotCarb) is a white,dense, free-flowing granular materi-al which is easy to handle andstore.

    The process starts with potassiumchloride, obtained from theCanadian province ofSaskatchewan. Through an elec-trolytic conversion of the KCl salt,potassium hydroxide (causticpotash, KOH), chlorine (Cl2) andhydrogen (H2) are produced. Thehydrogen is a fuel source while thechlorine has numerous importantand varied applications. Liquidcaustic potash and carbon dioxideare the only raw materials requiredfor producing PotCarb.

    The dry potassium carbonate caneasily be dissolved in water to forma liquid solution. Typically a 47%solution is recommended as thiscapitalizes on the highest concen-tration with the lowest freezingpoint (3F). This minimizes han-dling problems during colderweather.

    The chemical equation for thisprocess is simply:

    2 KCl + 2 H2O 2 KOH + H2 + Cl2

    2 KOH + CO2 K2CO3 + H2O

    The favorable logistics of this pro-duction facility cover a wide spec-trum of advantages:

    t Largest domestic facility, uti-lizing four reactors in twoplants;

    t Dry and liquid forms availablein various packaging units;

    t Vertically integrated with on-site production of liquid caus-tic potash (KOH), the key rawmaterial;

    t Geographical location in prox-imity to Gulf and Easterncoast ports, allowing for time-ly export shipments;

    t Electric power for raw materialconversion and plant opera-tions is readily available froma nearby TVA plant.

    As a side note, potassium carbon-ate cannot be made by the Solvayprocess used for sodium carbonate(Na2CO3).

    The flow diagram for the manu-facturing process is shown on thenext page:

    lll. Manufacturing Process

  • Armand Products Company

    Handbook K2CO3 7

    Flow Chart of Manufacturing Process

  • Armand Products Company

    8 K2CO3 Handbook

    Armand Products produces potassi-um carbonate in granular and liq-uid form to satisfy the requirementsof its customers. Each material con-forms to the high standards ofchemical purity and physical prop-erties essential for our extensive andvaried customer base. ArmandProducts anhydrous potassium car-bonate is white, dustless, dense,free-flowing granular product.Several grades of dry PotCarb thatdiffer in their typical granulationranges are available. In addition, awater solution in the form of a 47%solution is typically provided.

    Requests can be made through theArmand Products Technical Servicestaff for the following literature:

    Sales Specificationproduct grade sheets listing para-meters and their limits

    Technical Informationdata sheets covering chemicaland physical properties

    TThhee cchheemmiiccaall ppaarraammeetteerrss iinncclluudd--eedd iinn tthhee ssttaannddaarrdd ssaalleess ssppeecciiffii--ccaattiioonnss ffoorr AAnnhhyyddrroouuss PPoottaassssiiuummCCaarrbboonnaattee aarree::

    K2CO3 KOHKCl H2ONa K2SO4As FeHg NiHeavy Metals (as Pb)

    PPhhyyssiiccaall PPrrooppeerrttiieess::(not specification items)

    Particle SizeTypically material is between 18and 80 mesh for granular andthrough 325 mesh for groundmaterial.

    Bulk Density75 - 84 lb/ft3 (granular, varies bygrade); 37 lb/ft3 (extra fine)

    Melting Point891C

    Solubility in Water112 grams in 100 grams water at20C

    AppearanceWhite, granular, free-flowing

    Grades of Potassium CarbonateIV.

  • Armand Products Company

    Handbook K2CO3 9

    Iron, steel, stainless steel, rubberlined steel or phenolic lined steel isrecommended. If heated to 120F, the potential foriron contamination exists.Polyethylene drums can be used forliquid storage and handling atambient temperatures.Aluminum, zinc, brass, bronze, andcopper are NOT recommended dueto the potential for a reaction.

    Experience with the various poly-meric materials of construction islimited. Additional data based oncustomers own experiences shouldbe considered. The weight of thePotCarb must be factored into thestructural constraints of polymericmaterials. The following informa-tion is therefore offered as a startingpoint:

    t Polyethylene and propylenecan be used if not exposed totemperatures beyond that rec-ommended for each polymer.Possible deformation of poly-mer surface may occur.Caution is advised duringprocesses that generate heat,e.g., solubilization of drypotassium carbonate.

    t Polyester is NOT recommend-ed.

    t Polyvinyl chloride (PVC) hasbeen reported to be acceptablebut caution is advised for pos-sible embrittlement. Regularinspection and proper usageprocedures may allow goodservice from this material.

    A. ANHYDROUS POTASSI-UM CARBONATE

    PPiippiinnggPneumatic systems require 4 inchminimum piping with four footradius curves. Gravity feed systemsshould be 6 inch diameter or larger.

    VVaallvveessButterfly or slide gate valves are typ-ical, however, the butterfly type arepreferred for humid conditions.

    BBlloowweerrssPneumatic unloading requires blow-ers that are generally 500 - 600 CFMand operate at 10 lbs. of pressure. Inhumid conditions, the transfer airshould be pulled through a desic-cant bed to provide dry transfer air.The dryer should be checked peri-odically and replaced as needed.

    SSttoorraaggee SSiilloossCapacity should hold at least 1.5times the size of a normal ship-ment. A dry air purge in wet humidconditions will ease the handling ofproduct. A 45 slope to the silo bot-tom is recommended. A bag houseis recommended for filtering outdust from the transfer air during thepneumatic unloading of product.Storage silos should be steel, linedsteel or stainless. A more thoroughdiscussion of the recommendationsfor bulk storage can be found insection VIII.D.

    Materials of ConstructionV.

  • Armand Products Company

    10 K2CO3 Handbook

    B. LIQUID POTASSIUMCARBONATE

    PPiippeelliinneessA two inch minimum pipeline

    with a 3 inch minimum on the suc-tion side of the pump is recom-mended. Long sections of outdoorpiping should be heat traced andinsulated. Experience has demon-strated that flanged connectionswith alkali-resistant gaskets willminimized the potential for leaks.All piping should be installed witha slight slope to ensure completedrainage. Loops and pockets are tobe avoided.

    PPuummppssCentrifugal and rotary types with

    all iron construction may be used. Adeep packing gland is desired toprevent leakage at the pump shaft.Graphite/asbestos packing materialis recommended for potassium car-bonate solution service.

    VVaallvveessGlobe, angle, gate, and plug

    valves may be employed to controlflow rates and for line shutoffs.Valve construction of cast iron,steel, and stainless steel (Type 316and 304) is recommended.

    SSttoorraaggee TTaannkkssFabrication specifications require

    at least 3/8 inch wall thickness forunits larger than 10,000 galloncapacity and a 1/4 inch wall forsmaller capacities. The withdrawalpipe connection should be a fewinches above the bottom of thetank. To facilitate tank cleaning, adrain connection should beinstalled at the lowest point in thetank.Rubber or phenolic based epoxiescan be used for lining steel storagetanks where prevention of iron con-

    tamination is critical. However, rub-ber does not withstand high tem-peratures.

    Storage tanks in cold climatesshould be insulated with 2 inchesof polyurethane insulation to main-tain pumpable conditions andshould have an internal or externalheat source to make temperatureadjustments.

    Some plastics are also acceptablefor small tank construction (gener-ally less than 10,000 gallons). Poly-propylene, polyethylene, PVC,CPVC and FRP can be used. Poly-propylene is the most commonlyused plastic for storage tanks.

    Further discussion with ourTechnical Service staff on the appro-priate materials of construction andequipment for handling potassiumcarbonate is encouraged.

  • Armand Products Company

    Handbook K2CO3 11

    SHIPMENT OF POTASSIUM CARBONATEPotassium carbonate can be shippedin various types and sizes of packag-ing. Armand Products TechnicalService is available to discuss allpossible options and can assist thecustomer in determining the mostadvantageous method to receivethis product. Examples of the typi-cal containers available are:

    t 50 and 100 pound multiwallpaper bags

    t 400 pound fiber drumst 2000 pound bulk bagst hopper and pneumatic truckst hopper and pneumatic railcars

    Factors that determine the typeof package include the quantity tobe used, as well as the customerslocation, unloading system andstorage facilities. Since bulk ship-ments can be made in trucks andrailcars, it is better to determine themost advantageous delivery methodthrough an economic survey foreach individual case.

    BAG AND DRUMSHIPMENTThe multiwall kraft bags used byArmand Products are constructedwith a polyethylene moisture barri-er to better protect product qualityduring storage. Fiber drums can befurnished with a polyethylene linerupon request. Bag and drum specifi-cations are available from ArmandProducts Technical Service depart-ment.

    Although receipt of the materialin bags or drums may not offer theeconomic advantage of bulk, thereare other factors which may promptthe choice of this type of packaging.

    The use of bags or drums simplifiesdistribution when potassium car-bonate is used in small quantities atseveral locations. Individual pack-ages also eliminate the necessity ofbatch weighing potassium carbon-ate for various requirements. Noexpensive or elaborate equipment isneeded to unload or handle baggedor drummed potassium carbonateshipments. The use of drums andbags makes potassium carbonateavailable to even the smallest indus-trial consumer.

    Trucks and rail cars for this serviceare checked internally for the pres-ence of moisture, previously loadedmaterial, and general surface deterio-ration.

    BULK BAG SHIPMENTThis larger form of individual packag-ing offers a unique advantage forthose that meet the space require-ments but do not have the capabilityto unload and store truck or rail carshipments. Typically each bag isfilled with 2,000 pounds of potassi-um carbonate. For truckload quanti-ties however, different weights can befilled to meet the customers batchrequirements. These bulk bags aremade of a woven polypropylene fab-ric with a polyethylene liner as amoisture barrier. This is considered aone trip package to ensure the safehandling integrity of the bag and tomaintain product quality. Bulk bagsfilled with a metric ton (2205pounds) of product have become thepreferred package for export ship-ments.

    Shipping PackagesVl.

  • Armand Products Company

    12 K2CO3 Handbook

    BULK SHIPMENTBulk quantities of potassium car-bonate may be shipped in coveredhopper cars, pneumatic unloadingcars, hopper trucks, or self-unload-ing pneumatic trucks. The choicedepends on the quantity used, aswell as the customers location,unloading system and storage facili-ties. Details of the various optionscan be discussed with TechnicalService personnel.

    Covered hopper cars are speciallydesigned to handle products such aspotassium carbonate and providethe most satisfactory method ofbulk shipment. These self-discharg-ing cars are equipped with weather-proof hatches and three or four bot-tom outlet gates which provide pro-tection from outside contamina-tion. The bottom outlets are nor-mally of the Enterprise or slidinggate type, measuring 13 x 24 or 13x 42 inches, with a clearance of 6 to9 inches over the rail that will varywith car design. Hopper cars, nor-mally available in 70 and 95 toncapacities, can be readily adapted tomechanical unloading systems.

    Pressure differential (PD) railroadcars are available to customers whohave an appropriate pneumatic sys-

    tem in place to handle unloading.Those who have a potential interestin receiving PD bulk railcar ship-ments are invited to discuss thisoption with Armand ProductsTechnical Service.

    Motor truck shipments havebeen found practical for bulk potas-sium carbonate, particularly wherethe distance is not excessive andthe customers consumption orlocation will not allow rail deliver-ies. The amount of material thatcan be carried is usually restrictedby the road limitations of the statesthrough which the haul is made,with a typical maximum weight of45,000 pounds. Truck designs canvary but hopper bottom dischargeor self-unloading pneumatic trucksare typical.

    The development of self-unload-ing trailers now enables consumers ofas little as 100 tons per year toreceive potassium carbonate in bulkwithout the necessity of providingcostly unloading equipment. Thetank-type trailer available for this ser-vice carries a self-contained unload-ing system which blows the materialinto the customers bin. (Figure 1,Page 15) It is operated by the dri-ver, who makes the complete deliv-ery. The receiving equipmentrequired by the customer is relativelysimple in structure and is easy toinstall. It consists of a vertical trans-mission line made with a four inchstandard pipe and four foot radiusbends with a tank vent through a fil-ter system to remove dust.

    Since shipments of potassiumcarbonate will be 20-23 tons by thisservice, a minimum storage capacityof 30-35 tons will usually be ade-quate for most plants. Conven-tional silos, tanks or existing storagefacilities can easily be adapted forthis system. The facility must bemoisture-tight and requires a stor-age tank vent dryer.Anhydrous and liquid forms of