1、Designation:D184586(Reapproved 2014)Standard Test Methods forChemical Analysis of Strontium Chromate Pigment1This standard is issued under the fixed designation D1845;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last r
2、evision.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 These test methods cover the chemical analys
3、is ofstrontium chromate pigment.1.2 The analytical procedures appear in the following order:SectionsStrontium by the Strontium Sulfate Method7 to 10Chromium by the Thiosulfate Method11 to 14Chloride Content15Sulfate Content16Moisture and Other Volatile Matter17Coarse Particles18Mass Color and Tintin
4、g Strength191.3 This values stated in SI units are to be considered thestandard.The values given in parentheses are for informationonly.1.4 This standard does not purport to address the safetyconcerns associated with its use.It is the responsibility of theuser of this standard to establish appropria
5、te 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 PigmentsD
6、387 Test Method for Color and Strength of ChromaticPigments with a Mechanical MullerD444 Test Methods for Chemical Analysis of Zinc YellowPigment(Zinc Chromate Yellow)D1193 Specification for Reagent Water3.Significance and Use3.1 These test methods may be used to confirm the statedstrontium oxide an
7、d chromium oxide content of strontiumchromate.4.Apparatus4.1 Gooch crucible.4.2 Electric Furnace,capable of 800C.5.Purity of Reagents5.1 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
8、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.5.2 Unless otherwise indicated
9、,references to water shall beunderstood to mean Type II of Specification D1193.6.Preparation of Sample6.1 Mix the sample thoroughly.Take a sufficient quantityfor chemical analysis and pass it through a No.325(4-m)sieve.STRONTIUM BY THE STRONTIUM SULFATEMETHOD7.Reagents7.1 Acetic Acid(glacial).7.2 Am
10、monium Hydroxide(1+3)Mix 1 volume of concen-trated ammonium hydroxide(NH4OH,sp gr 0.90)with 3volumes of water.1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Subcommittee D01.31 on Pigmen
11、t Specifications.Current edition approved Dec.1,2014.Published December 2014.Originallyapproved in 1961.Last previous edition approved in 2008 as D1845 86(2008).DOI:10.1520/D1845-86R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.o
12、rg.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 Soci
13、ety,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 7.3
14、Ethyl Alcohol,conforming to Formula No.2B or No.30of the U.S.Bureau of Alcohol,Tobacco,and Firearms.7.4 Hydrochloric Acid(1+1)Mix equal volumes of con-centrated hydrochloric acid(HCl,sp gr 1.19)and water.7.5 Sulfuric Acid(1+19)Mix 1 volume of concentratedsulfuric acid(H2SO4,sp gr 1.84)with 19 volume
15、s of water.8.Procedure8.1 Weigh to 0.1 mg about 0.5 g of the sample into a400-mL beaker.Add 40 mL of HCl(1+1)and heat the solutionto dissolve the pigment.Add 40 mL of ethyl alcohol until thechromium is reduced,as this is indicated by a dark colorationof the solution.Add to the solution 100 mL of wat
16、er andsufficient NH4OH(1+3)to form a slight persistent precipitate.8.2 Add HCl dropwise until the precipitate just redissolves(Note 1).Heat the solution to just under boiling and add 20 mLof H2SO4(1+19).Add 100 mL of ethyl alcohol and allow theprecipitate to settle for several hours or overnight.NOTE1For a cleaner precipitate,add HCl until a pH of 2.0 is reached,instead of adding HCl dropwise until the precipitate is just dissolved.Thenadd 25 mL of acetic acid to minimize the tendency of the sul
