1、Designation: D2350 90 (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
2、 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
3、 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 thesaf
4、ety 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
5、 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 antim
6、ony 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 calculate
7、d 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
8、 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 Analytic
9、al 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 indi
10、cated, 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 (KM
11、nO4)in1L 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(s
12、p 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 20
13、15. 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 an
14、d 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 Documen
15、t 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.
16、, 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 States110 to 12 g of K2SO4. Heat until all the antimony is dissolved,cool, d
17、ilute to 100 mL with water, add 1 to2gofsodium 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 mL with water, add 20 mL of HCl (sp gr 1.19) and titra
18、teto a faint pink tint with 0.1 N KMnO4solution.NOTE 1For normal routine control work, the reduction with sodiumsulfite may be eliminated. The material may be diluted to 250 mL, 20 mLof HCl added, and titrated immediately after cooling the sulfuric acid-potassium sulfate digestion.5.6 Potassium Sulf
19、ate (K2SO4).5.7 Starch-Iodate PaperImpregnate filter paper with asolution obtained by heating2gofstarch with 100 mL ofwater, and, after solution, adding 0.2 g of potassium iodate(KIO3) dissolved in 5 mL of water.5.8 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).5.9 Tartaric Acid.6. Pre
20、paration of Sample6.1 Separate and prepare the pigment in accordance withTest Method D2371.7. Procedure7.1 Transfer 0.3 g of a straight Sb2O3pigment, or 0.5 g ofa mixed pigment, to a 500-mL resistant-glass Erlenmeyer flask,add 15 mL of water and 25 mL of HCl (sp gr 1.19). Cover witha watch glass, wa
21、rm on the steam bath for 10 to 15 min todissolve the antimony oxide, wash off the cover, add 250 mLof water, and 15 mL of H2SO4(sp gr 1.84). Boil 2 min, cool to10 to 15C, and titrate to a faint pink tint with 0.1 N KMnO4solution. Calculate to Sb2O3.7.2 The procedure described in 7.1 gives only the a
22、ntimonyin the ous conditions. The following method gives the totalantimony (ous and ic forms): Transfer 0.3 g of a straight Sb2O3pigment, or 0.5 g of a mixed pigment, to a 500-mL resistant-glass Erlenmeyer flask, and add 15 mL of H2SO4(sp gr 1.84),10gofK2SO4, and a 9-cm filter paper (to furnish carb
23、on to actas a reducing agent). Place a funnel in the neck of the flask andheat until the solution becomes colorless. Cool, wash off thefunnel, dilute to 100 mL with water, add 1 to2gofNa2SO3,and boil until all the SO2is expelled. This expulsion is evidentwhen no blue color is obtained with starch-io
24、date paper (5.7).The volume will be reduced about one half. Dilute to 250 mLwith water, add 20 mL of HCl (sp gr 1.19), and titrate to a faintpink tint with 0.1 N KMnO4solution (Note 1).7.2.1 Calculate total antimony to Sb2O3. Subtract the Sb2O3found using the procedure given in 7.1 from the total Sb
25、2O3and calculate the residual Sb2O3to Sb2O5(multiply by thefactor 1.1098).7.3 Procedure in Presence of Appreciable Amounts of Iron:7.3.1 Treat1gofthemixed pigment, or 0.3 g of a tintedSb2O3pigment, in a covered 250-mL beaker with 5 mL ofwater and 20 mL of HCl (sp gr 1.19). Heat on the steam bathfor
26、15 min, cool, wash off the cover, add3goftartaric acid and100 mL of hot water, and digest a few minutes. Filter, catchingthe filtrate in a 500-mL resistant-glass Erlenmeyer flask. Washthoroughly with hot water, dilute to 300 mL with hot water, andpass in H2S until the precipitation is complete. (If
27、the samplecontains no insoluble matter, dissolve directly in a 500-mLresistant-glass Erlenmeyer flask, add tartaric acid, dilute, andpass in H2S.)7.3.2 Filter, wash with water containing H2S until free fromHCl, return paper and precipitate to the Erlenmeyer flask, add15 mL of H2SO4(sp gr 1.84) and 1
28、0 g of K2SO4, place a funnelin the neck of the flask, and heat until the solution is colorless.Cool, wash off the funnel, dilute to 100 mL with water, add 1to2gofsodium sulfite (Na2SO3), and boil until all the SO2isexpelled. This expulsion is evident when no blue color isobtained with starch-iodate
29、paper (5.7). The volume will bereduced about one-half. Dilute to 250 mL with water, add 20mL of HCl (sp gr 1.19), and titrate to a faint pink tint with 0.1N KMnO4solution (Note 1).8. Calculation8.1 Calculate the percent antimony, B,asSb2O3as follows:B 5AVS3100 (1)where:A =Sb2O3equivalent of the KMnO
30、4solution, g/mL,V = KMnO4solution required, mL, andS = sample used, g.9. Precision9.1 Data are not available to determine the precision of 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.
31、1 antimony oxide; white pigmentD2350 90 (2015)2ASTM 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,
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