ASTM_D_2350_-_90_2015.pdf

Designation:D235090(Reapproved 2015)Standard Test Method forAntimony Oxide in White Pigment Separated From Solvent-Reducible Paints1This standard is issued under the fixed designation D2350;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers the determination of the totalantimony oxide in white pigment separated from solvent-reducible paints.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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:2D1193 Specification for Reagent WaterD2371 Test Method for Pigment Content of Solvent-Reducible Paints3.Summary of Test Method3.1 The pigment is dissolved in hydrochloric acid(HCl).Sulfuric acid(H2SO4)is added.The mixture is titrated withpotassium permanganate(KMnO4)and calculated to antimonyoxide(Sb2O3)which gives antimony in the ous condition.3.2 The pigment is dissolved in H2SO4with potassiumsulfate(K2SO4)and reduced.Sodium sulfite(Na2SO3)is addedand sulfur dioxide gas(SO2)is expelled.The solution is dilutedand HCl added after which the solution is titrated with KMnO4,which gives total antimony calculated to Sb2O3.3.3 Sb2O3from ous condition is subtracted from total Sb2O3and residual Sb2O3is calculated to Sb2O5.3.4 The procedure is also described for antimony oxide inpresence of large amounts of iron.4.Significance and Use4.1 Antimony trioxide is often used in fire-retardant paints,so it is useful to formulators and users to be able to monitor theamount of this compound in whole paints.5.Reagents5.1 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.3Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean Type II reagent gradewater in accordance with Specification D1193.5.3 Hydrochloric Acid(sp gr 1.19)Concentrated HCl.5.4 Hydrogen Sulfide(H2S).5.5 Potassium Permanganate,Standard Solution(0.1 N)Dissolve 3.2 g of pure potassium permanganate(KMnO4)in 1L of water,let stand 8 to 14 days,and siphon off the clearsolution(or filter through a glass filter).For use in determiningantimony,the KMnO4solution is best standardized as follows:To 0.25 g of pure metallic antimony in a 500-mLresistant-glassErlenmeyer flask,add 12 to 15 mL of H2SO4(sp gr 1.84)and1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved June 1,2015.Published June 2015.Originallyapproved in 1965.Last previous edition approved in 2010 as D2350 90(2010).DOI:10.1520/D2350-90R15.This standard has been approved for use by agencies of the Department ofDefense to replace Method 7016 of Federal Test Method Standard No.141.Consultthe DoD Index of Specifications and Standards for the specific year of issue whichhas been approved by the Department of Defense.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.3Reagent 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.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 10 to 12 g of K2SO4.Heat until all the antimony is dissolved,cool,dilute to 100 mLwith water,add 1 to 2 g of sodium sulfite(Na2SO3),and boil until all the SO2is expelled.This expulsionis evident when no blue color is obtained with starch-iodatepaper(5.7).The volume will be reduced about one half.Diluteto 250 mLwith water,add 20 mLof HCl(sp gr 1.19)and t