ASTM_C_867_-_94_2014.pdf

Designation:C86794(Reapproved 2014)Standard Test Method forSoluble Sulfate in Ceramic Whiteware Clays(PhotometricMethod)1This standard is issued under the fixed designation C867;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of solublesulfate ions present in water or a filtrate by means of aphotometer measuring the turbidity of precipitated bariumsulfate.A method of standardizing the photometer for this testmethod is also given.1.2 Soluble sulfate ions may be removed from clays orclay-water slurries by leaching with water during mixing andsubsequent filter pressing.To remove all the sulfate ions wouldrequire an impractical number of washings;therefore,this testmethod should be considered a control test and not a quanti-tative analysis for SO4ions.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C324 Test Method for Free Moisture in Ceramic WhitewareClaysD1193 Specification for Reagent Water2.2 American Chemical Society Document:Specification for Reagent Chemicals33.Apparatus3.1 Balance,accurate to 0.0001 g.3.2 High-Speed Mixer.3.3 Filter Press,capable of operating at 690 kPa(100 psi).3.4 Glass Beakers,Erlenmeyer Flasks.3.5 Transfer Pipets.3.6 Spectrophotometer and accessories.3.7 Measuring Spoon,to hold approximately 0.2 g of BaCl2or THQ Cup.3.8 Other usual laboratory equipment,including timers,etc.4.Reagents4.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused,provided it is first ascertained that the regent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.4.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean Type IV Grade reagentwater as defined in Specification D1193.4.3 Barium Chloride(BaCl2H2O)crystals,20 to 30 mesh.4.4 Salt-Acid ReagentHowever,it can be prepared from:23.6 ml HCl,253.0 gm NaCl,976.4 ml distilled water.Thissolution should be stored in an automatic pipettor for accuratemeasurement.4.5 Glycerine Reagenta mixture of equal volumes of c.p.glycerine and reagent grade water or it may be purchased froma laboratory supply house.This solution should be stored in anautomatic pipettor for accurate measurement.4.6 Standard Sulfate Solutiona solution of c.p.sodiumsulfate in reagent grade water at a concentration which containsexactly 100 ppm of sulfate ion.1This test method is under the jurisdiction ofASTM Committee C21 on CeramicWhitewares and Related Products and is the direct responsibility of SubcommitteeC21.04 on Raw Materials.Current edition approved Jan.1,2014.Published February 2014.Originallyapproved in 1977.Last previous edition approved in 2007 as C867 94(2007).DOI:10.1520/C0867-94R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American Chemical Society,1155 16th Street,NW,Washington,DC 20036.4Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the testing of reagents notlisted by the American Chemical Society,see Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmaceutical Convention,Inc.(USPC),Rockville,MD.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Standardization of Apparatus5.1 It should be noted that the instrument requires about 30min to warm up.Keep a blank cell in the instrument when asample is not in the holder.For SO4determination,the filterwavelength should be set at 550 nm.5.2 Using the appropriate pipettes,measure 25 ml of thestandard 100 ppm solution into a 125 ml Erlenmeyer flask.Add5 ml of glycerine reagent and 2.5 ml of salt-acid reagent andstir thoroughly.5.3 Fill a clean transmission cell with the prepared solution.Be sure to wipe off any droplets of water or solution on theoutside of the cell since this may interfere with the readings.5.4 Insert the cell into the cell holder.Put the 550 nm filterin place and adjust the transmission to read 100.0 percent.5.5