1、Designation: D 715 86 (Reapproved 2008)Standard Test Methods forAnalysis of Barium Sulfate Pigment1This standard is issued under the fixed designation D 715; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、. 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 l
4、imita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:2D 185 Test Methods for Coarse Particles in PigmentsD 280 Test Methods for Hygroscopic Moisture (and OtherMatter Volatile Under the Test Conditions) in PigmentsD 1193 Specification for Reagent WaterD 1208 Test Methods for Common Prop
5、erties of CertainPigmentsE 832 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 manufactur
6、e 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.3O
7、ther 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 ofSpecific
8、ation D 1193.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
9、 water.5.5 Methyl Red Indicator SolutionDissolve 0.2 g of me-thyl 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, add3g
10、ofNa2CO3, 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 inso
11、luble 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,and add NH4OH (sp gr 0.90) until the
12、 solution is slightlyalkaline. Add 6 mL of HCl (1+1), and dilute to 300 mL.1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibility of CommitteeD01.31 on Pigment Specifications.Current edition appr
13、oved Feb. 1, 2008. Published February 2008. Originallyapproved in 1943. Last previous edition approved in 2003 as D 715 86 (2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informat
14、ion, 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 LaboratoryChemi
15、cals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.3 Heat the solution to boiling,
16、 and add5gof(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
17、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 weigh as BaSO4.7. C
18、alculation7.1 Calculate the percent of BaSO4as follows:BaSO4,%5 P/S1! 3 100 (1)where:P = BaSO4,g,andS1= sample used, g.FERRIC OXIDE8. Apparatus8.1 Colorimetric ApparatusNessler type or other similar100-mL colorimetric tubes.9. Reagents9.1 Ammonium Thiocyanate Solution (76.1 g/L)Dissolve76 g of ammon
19、ium thiocyanate (NH4CNS) in water and diluteto1L.9.2 Iron, Standard Solution (100 mL = 0.00002 g Fe)Dilute and divide a ferric solution of known iron content so asto obtain 0.4 mg of iron. Dilute the solution to 2 L with watercontaining 200 mL of iron-free H2SO4.9.3 Potassium Permanganate Solution (
20、0.1 g/L)Dissolve0.1 g of potassium permanganate (KMnO4) in water and diluteto1L.9.4 Standard Color SolutionMix thoroughly 10 parts byvolume of NH4CNS and 90 parts by volume of standard ironsolution (100 mL = 0.02 mg Fe). One hundred millilitres of thesolution will thus contain 0.000018 mg of Fe.9.5
21、Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).9.6 Sulfuric Acid (1+1)Carefully mix 1 volume of con-centrated H2SO4(sp gr 1.84) with 1 volume of water.10. Procedure10.1 Dissolve the soluble portion of a 1-g specimen inH2SO4(1+1), filter, and wash, keeping the volume of thesolution under
22、 100 mL. Oxidize any iron present in the filtrateby adding potassium permanganate (KMnO4) until a faint pinkcolor is obtained. Dilute the solution to 100 mL and pour intoa buret graduated in 0.1-mL divisions.10.2 Pour 100 mL of the standard color solution into a100-mL colorimetric tube. Into a secon
23、d colorimetric tube pour10 mL of concentrated H2SO4(sp gr 1.84) and 10 mL ofNH4CNS, dilute to 60 or 70 mL and then add the test solutionfrom the buret until the depth of color thus produced ondilution to 100 mLexactly matches that of the standard. Recordthe number of millilitres required.11. Calcula
24、tion11.1 Calculate the percent of Fe2O3as follows:Fe2O3,%5 I 3 1.4298!/S2# 3 100 (2)where:I = iron in standard, g,1.4298 = Fe2O3Fe25159.694111.694, andS2= sample used, g.HYDROGEN ION CONCENTRATION12. Procedure12.1 Determine the pH in accordance with Test MethodsD 1208.MATTER SOLUBLE IN WATER13. Proc
25、edure13.1 Determine the amount of water soluble materialpresent in accordance with Test Methods D 1208.MOISTURE AND OTHER VOLATILE MATTER14. Procedure14.1 Determine the moisture and other volatile matter inaccordance with Test Methods D 280.COARSE PARTICLES(Total Residue Retained on No. 325 (45-m) S
26、ieve)15. Procedure15.1 Determine the coarse particles in accordance with TestMethods D 185.FREE SILICA16. Reagent16.1 Heavy Liquid (sp gr 2.9)Dissolve 4 parts by weightof potassium iodide (KI) in 6 parts of warm water, and add,while stirring constantly, 5 parts of mercuric iodide (HgI2).Evaporate ov
27、er a hot plate or gas flame, protected by screencloth, until a light crystalline scum forms. Cool, and filterthrough heavy paper. The solution will be a clear, deep, ambercolor of about 3.2 specific gravity. All filter washings showinga yellow color should be saved and evaporated. Determine the3.2 s
28、pecific gravity accurately by means of a specific gravitybottle, and correct the solution to a specific gravity of 2.9 atroom temperature by adding water. Prepare approximately 200mL of the solution.17. Procedure17.1 Carefully weigh 10 g of the finely ground dry bariumsulfate pigment and transfer to
29、 a carefully dried 125-mL clearglass separatory funnel of the long narrow type. Add 100 mLof the heavy liquid (sp gr 2.9), stopper, and shake well toliberate any air bubbles that might adhere to the particles, andD 715 86 (2008)2also to break up all agglomerates. Set the separatory funnelaside and a
30、llow to stand in a perpendicular position for 2 h, orfor a sufficient time for the particles to rise or sink.17.2 Draw off the heavy particles through the stopcock intoa beaker along with 75 mL of the liquid. Add 50 mL of freshheavy liquid (sp gr 2.9) to the float particles and liquidremaining in th
31、e separatory funnel and repeat the procedure asdescribed in 17.1.17.3 Draw off the heavy particles along with 75 mL of theliquid and add to those drawn off in accordance with 17.1,leaving the float particles in the funnel. Wash the particlesremaining in the funnel with fresh heavy liquid (sp gr 2.9)
32、,filter through a No. 2/0 paper (see Specification E 832), andwash free of solution with warm water.17.4 Transfer the filter paper and silica to an ignition cup,dry, and ignite carefully in an electric furnace or over a flameto keep mechanical loss at a minimum. Weigh the floatedmaterial, and transf
33、er to a tared platinum dish or crucible. Add20 mL of hydrofluoric acid (HF) and 3 drops of H2SO4(1+1),evaporate to dryness, and ignite carefully to expel all fumes.Cool and weigh. The loss in weight represents the free silica inthe floated material.18. Calculation18.1 Calculate the percent of free S
34、iO2as follows:Free SiO2,%5 A/S3! 3 100 (3)where:A = SiO2,g,andS3= sample used, g.19. Precision and Bias19.1 The precision and bias of these test methods has notbeen determined.20. Keywords20.1 analysis of pigment; barium sulfate; barium sulfatecontent; barium sulfate pigment; ferric oxide in barium
35、sulfate;free silica in barium sulfateASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the ri
36、skof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of th
37、is standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake
38、 your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 715 86 (2008)3
