1、Designation: D3970 05 (Reapproved 2017)Standard Test Method forCerium in Paint Driers by Oxidimetric Determination1This standard is issued under the fixed designation D3970; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、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 titrimetric determination ofcerium in liquid cerium and rare earth paint driers and uti
3、lizesferrous ammonium sulfate.1.2 This test method is not applicable to dryer blends.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associate
4、d 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. For a specifichazard statement, see Section 7.1.5 This international standard was developed in accor-dan
5、ce with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Sta
6、ndards:2D444 Test Methods for Chemical Analysis of Zinc YellowPigment (Zinc Chromate Yellow)D600 Specification for Liquid Paint DriersD1193 Specification for Reagent WaterE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals (Withd
7、rawn 2009)3E300 Practice for Sampling Industrial Chemicals3. Summary of Test Method3.1 The organic constituents of the liquid drier specimen areeliminated by treatment with nitric, sulfuric, and hydrochloricacids, and the cerium is converted to cerous sulfate. The ceroussulfate is oxidized to ceric
8、sulfate with sodium bismuthate andtitrated with standard ferrous ammonium sulfate.4. Significance and Use4.1 This test method may be used to confirm in the presenceof rare earths the stated cerium content of liquid pure cerium orrare earth driers manufactured for use in the coatings industry.5. Inte
9、rferences5.1 This test method is specific for cerium in the presence ofrare earth metals. Other drier metals with more than onevalence may interfere and should be absent.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended tha
10、tall reagents purchased or prepared shall conform to thespecifications of the Committee on Analytical Reagents of theAmerican Chemical Society, where such specifications areavailable.4Other grades may be used, provided it is firstascertained that the reagent is of sufficiently high purity topermit i
11、ts use without lessening the accuracy of the determi-nation.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Type II of Specification D1193.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Co
12、atings, Materials, andApplications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved July 1, 2017. Published July 2017. Originally approvedin 1980. Last previous edition approved in 2011 as D3970 05 (2011). DOI:10.1520/
13、D3970-05R17.2For 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 website.3The last approved version of this historical sta
14、ndard is referenced onwww.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 Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K
15、., 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 StatesThis international standard was developed in accordance with internat
16、ionally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.16.3 Ceric Sulfate Solution, Standard (0.1 N)Standar
17、dized0.1 N solutions of ceric sulfate (Ce(SO4)2)in1N sulfuric acidmay be purchased or prepared.56.4 Ferroin Indicator (0.025 M)Orthophenanthroline fer-rous complex indicator.66.5 Ferrous Ammonium Sulfate Solution, Standard (0.1M)Standardized ferrous ammonium sulfate (FeSO4(NH4)2SO4), 0.1 M, may be p
18、urchased or prepared in thefollowing manner. Dissolve 39.2 g of ferrous ammoniumsulfate in 250 mL of distilled water and add 20 mL ofconcentrated sulfuric acid with stirring. Dilute to 1 L in avolumetric flask and standardize as follows:6.5.1 Pipet duplicate 20.0-mL portions of standard 0.1 Nceric s
19、ulfate solution into 400-mL beakers and add 200-mL of1.5 N sulfuric acid. Titrate with 0.1 N ferrous ammoniumsulfate solution as described in 6.6. Calculate the molarity, M,of this approximately 0.1 M solution as follows:M 5 V2N/V1(1)where:V2= ceric sulfate solution, mL,N = normality of ceric sulfat
20、e solution, andV1= ferrous ammonium sulfate solution, mL.6.6 Ferrous Ammonium Sulfate Solution, Standard (0.01M)Transfer 100 mL of the standardized 0.1 M ferrousammonium sulfate solution from a volumetric flask to a 1-Lvolumetric flask and dilute with distilled water. This 0.01 Mferrous ammonium sul
21、fate solution is designated as M2.Alternatively, 0.2 N ferrous ammonium sulfate solution (seeTest Methods D444) may be used and diluted to 0.01 M inaccordance with 6.5.6.7 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).6.8 Nitric Acid (sp gr 1.42)Concentrated nitric acid(HNO3).6
22、.9 Sodium Bismuthate (NaBiO3)7The grade required is ayellow powdery solid. If it is any other color it has decomposedand fresh material should be obtained.6.10 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).6.11 Sulfuric Acid (1 + 49, 2 %)Dilute 10 mL of theconcentrated sulfuric acid (H
23、2SO4) to 500 mL with water.6.12 Sulfuric Acid (1.5 N)Dilute 16.7 mL of concentratedsulfuric acid (H2SO4) to 400 mL with water.7. Precautions7.1 Use only a rubber bulb aspirator for pipetting liquids.8. Sampling8.1 Take a small sample of liquid drier from bulk using theprocedures in Practice E300 app
24、ropriate for the size of con-tainer: Bottle Sampling section for tanks and tank cars or TubeSampling section for drums and cans.NOTE 1Liquid driers are normally homogeneous so that only simplephysical tests, such as specific gravity or solids content, on top and bottomsamples from tanks are required
25、 to confirm that separation has notoccurred. Agitate drums in accordance with the Tube Sampling section ofPractice E300.8.2 Examine the sample of drier for sediment or suspendedmatter which, if present, is evidence of noncompliance with thePhysical Appearance requirements section of SpecificationD60
26、0.8.3 If the sample is homogeneous keep it in a stopperedvessel to prevent solvent evaporation prior to analysis.9. Procedure9.1 For the analysis use 1.0 g for 6 % of cerium and 2.0 g ormore for materials containing proportionally less cerium. Rareearth driers are generally 45 to 50 % cerium. Thus i
27、n theanalysis of 6 % rare earth driers, containing cerium, use 2.0 g.Weigh the specimen from a weighing bottle or syringe bydifference, to 0.5 mg, transferring the specimen to a 250-mLErlenmeyer flask.9.2 Place the flask on a hot plate and warm to volatilizesolvent (Note 2). Cool the flask.NOTE 2It
28、is easier to volatilize the solvent than to destroy it with acid.9.3 Under a hood, add 10 mL of HNO3and 10 mL of HClto the specimen in the flask. Add boiling aids, heat strongly ona hot plate, and boil down to 2 to 3 mL. Repeat the acidaddition and boiling down.NOTE 3Sulfuric acid is not added at th
29、e beginning of the digestionbecause it carbonizes the material making it more difficult to digest.9.4 Add 10 mL of concentrated H2SO4(Note 3), and 10 mLof HNO3, and heat strongly on the hot plate until the evolutionof brown fumes ceases and white fumes appear. At this pointsalt precipitation causes
30、a tendency to bump which may beavoided by mixing while heating until the salt dissolves. Cool.All HCl must be removed before proceeding to 9.5. If thickfumes appear the HCl has been removed.9.5 Add 100 mL of 2 % H2SO4, and 1.0 g of NaBiO3, andbring to a boil. Cool.9.6 Vacuum filter through a medium
31、fritted-glass filter, rinseflask and filter with 2 % H2SO4, and wash the filter with anadditional 150 mL of 2 % H2SO4. The filter may be used forseveral determinations without cleaning. When it plugs, it canbe cleaned easily with HCl.9.7 Dilute the solution to approximately 400 mL with waterand titr
32、ate with 0.01 M ferrous ammonium sulfate until the5The sole source of supply of reagent grade 0.1 N solution of ceric sulfate in 1N sulfuric acid, known to the committee at this time is G. Frederick Smith Co. If youare aware of alternative suppliers, please provide this information to ASTMInternatio
33、nal Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.6The sole source of supply of 0.025 M ferroin indicator, known to the committeeat this time is G. Frederick Smith Co. If you are aware of alternative suppliers,
34、please provide this information to ASTM International Headquarters. Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.7The sole source of supply of reagent grade sodium bismuthate, known to thecommittee at this time is Mallinck
35、rodt Co. If you are aware of alternative suppliers,please provide this information to ASTM International Headquarters. Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.D3970 05 (2017)2yellow color is barely perceptible. Add 1
36、drop of 0.025 Morthophenanthroline ferrous complex indicator and completethe titration. The color change is from clear to orange.10. Calculation10.1 Calculate the percent of cerium present, A, as follows:A 5V3M214.0!S(2)where:V3= ferrous ammonium sulfate solution, mL,M2= molarity of ferrous ammonium
37、 sulfate solution,14.0 = millimolar weight of cerium 100, andS = weight of specimen used, g.11. Precision811.1 The precision estimates are based on an interlaboratorystudy in which one operator in seven different laboratoriesanalyzed in duplicate on two different days samples of ceriumand rare earth
38、 driers containing 6 and 3 % cerium. Both werecommercially supplied drier solutions. The results were ana-lyzed statistically in accordance with Practice E180 and afterdeletion of one laboratorys results the within-laboratory coef-ficient of variation was found to be 0.75 % relative at 12 df andthe
39、between-laboratory coefficient of variation was 2.63 %relative at 10 df. Based on these coefficients, the followingcriteria should be used for judging the acceptability of resultsat the 95 % confidence level:11.1.1 RepeatabilityTwo results, each the mean of dupli-cate determinations, obtained by the
40、 same operator on differentdays, should be considered suspect if they differ by more than2.3 % relative.11.1.2 ReproducibilityTwo results, each the mean of du-plicate determinations, obtained by operators in different labo-ratories should be considered suspect if they differ by morethan 8.3 % relati
41、ve.12. Bias12.1 Bias cannot be determined for this method becausethere are no accepted standards for cerium in paint driers.13. Keywords13.1 cerium drier; drier analysis; ferrous ammonium sulfate;paint driers; rare earth driersASTM International takes no position respecting the validity of any paten
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