ASTM_D_715_-_86_2014.pdf

Designation:D71586(Reapproved 2014)Standard Test Methods forAnalysis of Barium Sulfate Pigment1This standard is issued under the fixed designation D715;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 These test methods cover the analysis of barium sulfatepigment.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 This standard does not purport to address the safetyconcerns associated with its use.It is the responsibility of theuser of this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2.Referenced Documents2.1 ASTM Standards:2D185 Test Methods for Coarse Particles in PigmentsD280 Test Methods for Hygroscopic Moisture(and OtherMatter Volatile Under the Test Conditions)in PigmentsD1193 Specification for Reagent WaterD1208 Test Methods for Common Properties of CertainPigmentsE832 Specification for Laboratory Filter Papers3.Significance and Use3.1 These test methods are used to determine the purity ofbarium sulfate and to determine the concentration of knownimpurities.This information is useful to producers and users asan aid in the manufacture of coatings.4.Purity of Reagents4.1 Reagent grade chemicals shall be used in all tests.Unless otherwise indicated,it is intended that all reagents shallconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society,where suchspecifications are available.3Other grades may be used,pro-vided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.4.2 Unless otherwise indicated,references to water shall beunderstood to mean reagent water conforming to Type II ofSpecification D1193.BARIUM SULFATE5.Reagents5.1 Ammonium Hydroxide(sp gr 0.90)Concentrated am-monium hydroxide(NH4OH).5.2 Ammonium Sulfate(NH4)2SO4).5.3 Hydrochloric Acid(sp gr 1.19)Concentrated hydro-chloric acid(HCl).5.4 Hydrochloric Acid(1+1)Mix equal volumes of con-centrated HCl(sp gr 1.19)and water.5.5 Methyl Red Indicator SolutionDissolve 0.2 g ofmethyl red in 100 mL of methanol,ethanol,or isopropanol.5.6 Sodium Carbonate Solution(30 g/L)Dissolve 30 g ofNa2CO3in water and dilute to 1 L.6.Procedure6.1 Weigh to 0.1 mg approximately 0.5 g of the sample intoa platinum crucible,add 3 g of Na2CO3,mix thoroughly,andfuse until the melt is clear.Allow the melt to cool and thenleach in a platinum dish with hot water until it is entirelydisintegrated.Filter on a close-texture paper and wash thor-oughly with hot Na2CO3solution(30 g/L).6.2 Transfer the filter paper containing the insoluble carbon-ates to a 250-mL beaker and acidify with concentrated HCl(spgr 1.19).Wash the fusion crucible with HCl(sp gr 1.19)so thatno barium is lost.Boil the solution,filter into a 600-mL beaker,and wash well with water.Add methyl red indicator solution,1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Committee D01.31 on Pigment Specifications.Current edition approved Dec.1,2014.Published December 2014.Originallyapproved in 1943.Last previous edition approved in 2008 as D715 86(2008).DOI:10.1520/D0715-86R14.2For 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 and add NH4OH(sp gr 0.90)until the solution is slightlyalkaline.Add 6 mL of HCl(1+1),and dilute to 300 mL.6.3 Heat the solution to boiling,and add 5 g of(NH4)2SO4dissolved in 40 mL of water.If low-grade material is beinganalyzed,the(NH4)2SO4solution should be added drop bydrop from a buret to minimize inclusion.If the barytes is arather pure product(95 to 99%BaSO4),this is not necessary,since the only nonvolatile constituents of the solution will bebarium salts.Allow the precipitate of BaSO4to digest for 4 hor overnight,and filter through a close-texture paper.Wash theprecipitate with as little cold water as possible(consistent withthe purity of the precipitate),ignite in an oxidizing atmosphere,and w