1、Designation: D2351 90 (Reapproved 2010)Standard Test Method forSulfide in White Pigment Separated from Solvent-ReduciblePaints1This standard is issued under the fixed designation D2351; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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 sulfidesulfur in white pigment separated from solvent-redu
3、ciblepaints.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 es
4、tablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D215 Practice for the Chemical Analysis of White LinseedOil Paints3D1193 Specification for Reagent WaterD2371 Test Method for Pigment Co
5、ntent of Solvent-Reducible Paints3. Summary of Test Method3.1 The extracted pigment is placed in a flask with mossyzinc. The hydrogen sulfide generated by addition of HCl reactswith lead nitrate in an absorption flask forming lead sulfide.The lead sulfide is dissolved with nitric acid (HNO3) and the
6、lead determined as lead sulfate in accordance with TestMethods D215.3.2 A rapid method is also described.4. Significance and Use4.1 Sulfide containing pigments such as lithopone have beenused in paints in varying degrees in the past years. As such itis useful to formulators and users to be able to m
7、onitor 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 Soci
8、ety,where such specifications are available.4Other 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 unders
9、tood to mean reagent grade waterconforming to Type II of Specification D1193.5.3 Ammoniacal Cadmium Chloride or Zinc SulfateSolutionDissolve8gofcadmium chloride (CdCl22H2O) in200 mL of water and add 200 mL of ammonium hydroxide(NH4OH, sp gr 0.90); or, dissolve 200 g of zinc sulfate(ZnSO47H2O) in 108
10、0 mL of water and 920 mL of NH4OH(sp gr 0.90).5.4 Hydrochloric Acid (sp gr 1.19)Concentrated HCl.5.5 Lead Nitrate, Alkaline Solution Into 100 mL ofpotassium hydroxide (KOH) solution (56 g in 140 mL ofwater) pour a saturated solution of lead nitrate (Pb(NO3)2) (250g in 500 mL of water) until the prec
11、ipitate ceases to redissolve,stirring constantly while mixing. Let settle, filter through aglass filter, and dilute the clear filtrate with an equal volume ofwater. About 3 volumes of the Pb(NO3)2solution will berequired for 1 volume of the KOH solution.5.6 Mossy Zinc.1This test method is under the
12、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, 2010. Published June 2010. Originallyapproved in 1965. Last previous
13、 edition approved in 2005 as D2351 90 (2005).DOI: 10.1520/D2351-90R10.2For 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
14、 website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see A
15、nalar Standards for LaboratoryChemicals, 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 State
16、s.5.7 Nitric Acid (1+4)Mix 1 volume of concentratedHNO3, (sp gr 1.42) with 4 volumes of water.5.8 Potassium Iodate, Standard SolutionDissolve 3.6 g ofpotassium iodate (KIO3) and 39 g of potassium iodide (KI) in1 L of water. For general work the theoretical sulfur titer of thissolution should be used
17、; for special work the solution may bestandardized against similar material, such as a lithopone ofknown sulfide sulfur content. The theoretical titer is based onstandard sodium oxalate (Na2C2O4) and is obtained as follows:To 300 mL of water in a 600-mL flask, preferably glass-stoppered, add 10 mL o
18、f HCl (sp gr 1.19) and1gofKI.Cooland add 10 mL of 0.1 N potassium permanganate (KMnO4)solution which has been standardized against Na2C2O4. Swirlgently, stopper, and let stand for 5 min. Titrate the liberatediodine with standard sodium thiosulfate (Na2S2O3) solutionuntil the color fades. Then add 10
19、 mL of starch solution andcontinue the titration until the blue color is destroyed. Repeatthe titration, except substitute 10 mL of the KIO3for theKMnO4solution. Calculate the normality of the KIO3solutionas follows.5.8.1 Standardization Calculation for Theoretical SulfurTiter:B 5v13 NV2(1)where:B =
20、 normality of KIO3,V1= standard Na2S2O3solution, mL, required to titrate 10mL of KMnO4solution,N = normality of standardized KMnO4solution, andV2= standard Na2S2O3solution, mL, required to titrate 10mL of KIO3solution.5.8.2 Standardization Against Known Pigment:C 5 A 3 S!/V 3 100! (2)where:A = sulfu
21、r in known pigment, %C = sulfide equivalent of the KIO3solution, g/mL,S = pigment, g, andV = KIO3solution required to titrate known pigment, mL.5.9 Starch Indicator (for Sulfur Titration)To1Lofboiling water add a cold suspension of6gofstarch in 100 mLof water and boil vigorously for 5 min. Cool the
22、solution, add6 g of zinc chloride (ZnCl2) dissolved in 50 mL of cold water,thoroughly mix, and set aside for 24 h. Decant the clearsupernatant liquid into a suitable container, add3gofKI,andmix thoroughly.5.9.1 (Optional) Prepare an emulsion of6gofsolublestarch in 25 mL of water, add a solution of1g
23、ofsodiumhydroxide (NaOH) in 10 mL of water, and stir the solution untilit gels. Dilute to 1 L with water, add3gofKI,andmixthoroughly.6. Preparation of Sample6.1 Separate and prepare the pigment for this determinationin accordance with Test Method D2371.7. Procedure7.1 Place 0.5 to1gofthepigment in a
24、 flask with about 10g of “feathered” or mossy zinc and add 50 mL of water; inserta stopper carrying a separatory funnel and an exit tube. Run in50 mL of HCl (sp gr 1.19) from the funnel, having previouslyconnected the exit tube to two absorption flasks in series; thefirst flask containing 100 mL of
25、alkaline lead nitrate solution,the second flask, 50 mL of the same solution as a safety device.After all of the acid has run into the evolution flask, heatslowly, finally boiling until the first appearance of steam in thefirst absorption flask.7.2 Disconnect, let the lead sulfide (PbS) settle, filte
26、r, andwash with cold water, then with hot water until neutral tolitmus paper and until the washings give no test for lead.Dissolve the PbS precipitate in hot HNO3(1+4) and determinethe lead as lead sulfate (PbSO4) in accordance with TestMethod D215.7.3 For very rapid work, the evolved hydrogen sulfi
27、de (H2S)may be absorbed in an ammoniacal CdCl2or ZnSO4solution(5.3) contained in two flasks connected in series, the contentsof the absorption flasks washed into a vessel with cold waterand diluted to about 1 L, acidified with HCl (sp gr 1.19), andtitrated with standard KIO3solution using starch ind
28、icator(5.9).8. Calculation8.1 Calculate the percent of sulfide sulfur, E, as follows:NOTE 1The percent of sulfide sulfur can be calculated from thepercent of total zinc and zinc soluble in acetic acid (2 to 3 %), assumingthe sulfide to be zinc sulfide (ZnS). See section on Total Zinc of TestMethod D
29、215.E 5 P 3 0.1054!/S 3 10C (3)where:P = PbSO4formed, g, andS = sample used, g.E 5 AV/S! 3 100 (4)where:A = sulfide equivalent of the KIO3solution, g/mL,V = KIO3solution required for titration of specimen, mL,andS = sample used, g.9. Precision9.1 Data are not available to determine the precision of
30、thistest method. There are no plans at present to obtain such data.This test method has been in use for several years and isconsidered acceptable.10. Keywords10.1 sulfide; white pigmentD2351 90 (2010)2ASTM International takes no position respecting the validity of any patent rights asserted in conne
31、ction 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 riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsi
32、ble technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful co
33、nsideration 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 your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100
34、 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D2351 90 (2010)3
