1、Designation: D 3989 01 (Reapproved 2006)Standard Test Method forTotal Rare Earth Metals in Paint Driers by EDTA Method1This standard is issued under the fixed designation D 3989; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. 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 This test method covers the titrimetric determination ofrare earth metals in liquid rare earth metal driers a
3、nd utilizesthe disodium salt of ethylenediaminetetraacetic acid dihydrate(EDTA).1.2 This test method is limited to the determination of therare earth metal content of a liquid rare earth metal drier thatdoes not contain other drier elements. The method is notapplicable to drier blends.1.3 This test
4、method has been tested in concentrations of6 % cerium and 6 % rare earth metals, but there is no reason tobelieve that it is not suitable for higher or lower drier metalconcentrations provided specimen size is adjusted accordingly.1.4 The values stated in SI units are to be regarded as thestandard.
5、The values given in parentheses are for informationonly.1.5 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 establish appro-priate safety and health practices and determine the applica-bilit
6、y of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 600 Specification for Liquid Paint DriersD 1193 Specification for Reagent WaterE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty ChemicalsE 300 Practi
7、ce for Sampling Industrial Chemicals3. Summary of Test Method3.1 A diluted solution of the drier is complexed with anexcess of EDTA, the pH adjusted to 5.0, and then titrated withzinc chloride solution to a xylenol orange end point.4. Significance and Use4.1 This test method may be used to confirm t
8、he statedcontent of a pure, liquid rare earth metal drier manufactured foruse in the coatings industry.5. Interferences5.1 Calcium does not interfere at low pH.5.2 All other cations that can be titrated with EDTAin acidicmedia will interfere and must not be present in the drier.6. Reagents6.1 Purity
9、 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 Society,where such specifications are available.3Other grades may beused, p
10、rovided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water conformingto Type II of Specification D 1193.
11、6.3 Ammonium ChlorideAmmonium Hydroxide BufferSolutionAdd 350 mL of concentrated ammonium hydroxide(NH4OH) to 54 g of ammonium chloride (NH4Cl), and diluteto 1 L with water.6.4 Ammonium Hydroxide (NH4OH), (1+1).6.5 Ascorbic Acid.6.6 Eriochrome Black T IndicatorMix and grind thor-oughly in a mortar a
12、 mixture of 0.2 g of Eriochrome Black Tand 100 g of sodium chloride. Store the mixture in a tightlystoppered bottle where it is stable indefinitely.6.7 EDTA, Standard Solution (0.01 M)Weigh about 3.73g of disodium salt of ethylenediaminetetraacetic acid dihydrateto the nearest 0.01 g, dissolve in wa
13、ter, and dilute to approxi-mately 1 L in a glass-stoppered bottle.6.8 Hydrochloric Acid (HCL), (1+1).6.9 Isopropyl Alcohol (99.5 %).1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommit
14、tee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1981. Last previous edition approved in 2001 as D 3989 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Serv
15、ice 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
16、 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Cons
17、hohocken, PA 19428-2959, United States.6.10 Sodium Acetate-Acetic Acid Buffer SolutionDissolve82 g of sodium acetate in water and dilute to 1 L. Adjust pH to5.0 with glacial acetic acid using a pH meter.6.11 Xylenol Orange IndicatorDissolve 0.2 g in 100 mLof water. Prepare fresh daily as required.6.
18、12 Zinc Chloride Solution, Standard (0.01 M)Weighabout 0.65 g of zinc ribbon (Note 1) to the nearest 5 mg on aglazed paper. Transfer to a 1-L volumetric flask and add 25 mLof dilute hydrochloric acid (1 + 3). Warm if necessary on asteam bath to dissolve the material completely. Cool, dilute tothe ma
19、rk with water, and mix thoroughly.NOTE 1Store the zinc ribbon in a tight container to prevent thesurface of the zinc from oxidizing.7. Sampling7.1 Take a small sample of liquid drier from bulk using theprocedure in Practice E 300 appropriate for the size of thecontainer, Section 19 for tanks and tan
20、k cars or Section 23 fordrums and cans.NOTE 2Liquid driers are normally homogeneous so that only simplephysical tests, such as specific gravity or solids content, on top and bottomsamples from tanks are required to confirm that separation has notoccurred. Agitate the drums in accordance with the sec
21、tion on ThiefSampling of Practice E 300.7.2 Examine the sample of drier for sediment or suspendedmatter which if present is evidence of noncompliance with thesection on Chemical and Physical Requirements of Specifica-tion D 600.7.3 If the sample is homogeneous keep it in a stopperedvessel to prevent
22、 solvent evaporation prior to analysis.8. Standardization8.1 Zinc Chloride Solution, Standard (0.01 M)Calculatethe molarity, M1, of the zinc chloride (ZnCl2) solution asfollows:M15 S1/65.37 (1)where:M1= molarity of ZnCl2solution,S1= grams of zinc used, and65.37 = grams of zinc per litre to producea1
23、Msolution.8.2 EDTA Solution, Standard (0.01 M)Transfer 40.00 mLof this solution from a buret into a 250-mL assay beaker orwide-mouth flask. Add 50 mL of isopropyl alcohol, 10 mL ofammonium chloride-ammonium hydroxide buffer solution, andabout 0.2 g of Eriochrome Black T indicator mixture (Note 3).Mi
24、x thoroughly by swirling. Titrate with the standard ZnCl2solution to the first permanent appearance of a red color.NOTE 3If the end point is overstepped, add 1.0 mL of the EDTAsolution to the mixture and titrate again with standard ZnCl2solution. Usetotal volume of each solution for the calculation.
25、8.2.1 Calculate the molarity, M2, of the EDTA solution asfollows:M25 V1M1/V2(2)where:V1= volume of ZnCl2solution, mL,M1= molarity of ZnCl2solution,V2= volume of EDTA solution, mL, andM2= molarity of EDTA solution.9. Procedure9.1 Check the clarity of the drier. If not clear, centrifuge aportion of th
26、e sample until it is clear, keeping the centrifugetube stoppered to prevent solvent evaporation.9.2 Place a few grams of the drier in a 50-mL Erlenmeyerflask fitted with a cork, through which passes a dropping tubeand a rubber bulb (or medicine dropper) and obtain the totalweight. Into a 400-mL beak
27、er weigh by difference to thenearest 0.5 mg the following specimen sizes: (a) 0.5 to 0.7 gfor 6 % rare earth metals or cerium, (b) 0.25 to 0.35 g for 12 %rare earth metals, and (c) proportionate amounts for more orless rare earth metals or cerium.9.3 Add about 5 mL of isopropyl alcohol and 2 mL of d
28、iluteHCl. Warm on a hot plate until the specimen dissolves.9.4 While still warm, add 0.4 to 0.5 g of ascorbic acid toreduce Ce (IV) and warm until any yellow color disappears.Add 70 mL of isopropyl alcohol and 40.0 mL of EDTAsolution.9.5 Place on the magnetic stirrer and add a stirring bar andthe el
29、ectrodes from the pH meter. Adjust the pH to approxi-mately 4.0 with 1 + 1 NH4OH, add 25 mL of sodium acetatebuffer, and adjust pH to 5.0 with 1 + 1 NH4OH or 1 + 1 HCl.9.6 Add approximately 1 mL of xylenol orange solution andtitrate with standardized zinc chloride solution from a yellow toorange end
30、 point.NOTE 4Use a good titration light to assist in detecting the end point.10. Calculation10.1 Calculate the percent total rare earth metals, T, presentas follows:T 5 V3M22 V4M1!14.0/S2(3)where:V3= volume of EDTA solution, mL,M2= molarity of EDTA solution,V4= volume of ZnCl2solution, mL,M1= molari
31、ty of ZnCl2solution,14.0 = millimolar weight of rare earth metals 3 100, andS2= grams of specimen used.11. Precision and Bias411.1 PrecisionThe precision estimates are based on aninterlaboratory study in which one operator in five differentlaboratories analyzed in duplicate on two different dayssamp
32、les of 6 % rare earth metal drier and 6 % cerium drier. Thedriers were commercially supplied. The results were analyzedstatistically in accordance with Practice E 180 and the within-laboratory coefficient of variation was found to be 0.4 %4Supporting data have been filed at ASTM International Headqu
33、arters and maybe obtained by requesting Research Report RR: D01-1030.D 3989 01 (2006)2relative at 10 df and the between-laboratory coefficient ofvariation was 1.6 % relative at 8 df. Based on these coeffi-cients, the following criteria should be used for judging theacceptability of results at the 95
34、 % confidence level:11.1.1 RepeatabilityTwo results, each the mean of dupli-cate determinations, obtained by the same operator on differentdays should be considered suspect if they differ by more than1.25 % relative.11.1.2 ReproducibilityTwo results, each the mean of du-plicate determinations, obtai
35、ned by operators in different labo-ratories should be considered suspect if they differ by morethan 5.3 % relative.11.2 BiasBias cannot be determined because there are noaccepted standards for rare earth metals in paint driers.12. Keywords12.1 analysis rare earth drier; EDTA; paint driersASTM Intern
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39、ards, 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 3989 01 (2006)3
