1、Designation: D 3970 05Standard Test Method forCerium in Paint Driers by Oxidimetric Determination1This standard is issued under the fixed designation D 3970; 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 This test method covers the titrimetric determination ofcerium in liquid cerium and rare earth paint driers and utilizesferrous am
3、monium 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, associated with its use.
4、 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 7.2. Referenced Documents2.1 ASTM Standards:2D 444 Test Methods for Chemica
5、l Analysis of Zinc YellowPigment (Zinc Chromate Yellow)D 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 ChemicalsE 300 Practice for Sampling Industrial Chemicals3. Summa
6、ry 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 sulfate with sodium bismuthate andtitrated with standard ferrous a
7、mmonium 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. Interferences5.1 This test method is specific for cerium in the presen
8、ce 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 thatall reagents purchased or prepared shall conform to thespecificat
9、ions of the Committee on Analytical Reagents of theAmerican Chemical Society, where such specifications areavailable3. Other grades may be used, provided it is firstascertained that the reagent is of sufficiently high purity topermit its use without lessening the accuracy of the determi-nation.6.2 P
10、urity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Type II of Specification D 1193.6.3 Ceric Sulfate Solution, Standard (0.1 N)Standardized0.1 N solutions of ceric sulfate (Ce(SO4)2)in1N sulfuric acidmay be purchased or prepared.46.4 F
11、erroin Indicator (0.025 M)Orthophenanthroline fer-rous complex indicator.56.5 Ferrous Ammonium Sulfate Solution, Standard (0.1M)Standardized ferrous ammonium sulfate (FeSO4(NH4)2SO4), 0.1 M, may be purchased or prepared in thefollowing manner. Dissolve 39.2 g of ferrous ammoniumsulfate in 250 mL of
12、distilled water and add 20 mL ofconcentrated sulfuric acid with stirring. Dilute to 1 L in avolumetric flask and standardize as follows:1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubco
13、mmittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved Jan. 1, 2005. Published February 2005. Originallyapproved in 1980. Last previous editions approved in 1999 as D 3970 80 (1999).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact AS
14、TM Customer Service 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 reage
15、nts notlisted by 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.4The sole source of supply of reagent grade 0.1 N solution o
16、f 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 ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical co
17、mmittee,1which you may attend.5The 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,please provide this information to ASTM International Headquarters. Your com-ments will receive careful consid
18、eration at a meeting of the responsible technicalcommittee,1which you may attend.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.5.1 Pipet duplicate 20.0-mL portions of standard 0.1 Nceric sulfate solution into 400-mL beakers and a
19、dd 200-mL of1.5 N sulfuric acid. Titrate with 0.1 N ferrous ammoniumsulfate solution as described in 9.9. 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 sulfate solution, andV1= ferrous ammonium sulfa
20、te 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 sulfate solution is designated as M2. Alter-
21、natively, 0.2 N ferrous ammonium sulfate solution (see TestMethods D 444) 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).6.9 Sodium Bismuthate (NaBiO3)6The grad
22、e 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 (H2SO4) to 500 mL with water.6.12 Sulfur
23、ic 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 E 300 appropriate for the size ofcontainer: Bo
24、ttle Sampling section for tanks and tank cars orTube Sampling 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 to confirm that separation has notoccu
25、rred. Agitate drums in accordance with the Tube Sampling section ofPractice E 300.8.2 Examine the sample of drier for sediment or suspendedmatter which, if present, is evidence of noncompliance with thePhysical Appearance requirements section of SpecificationD 600.8.3 If the sample is homogeneous ke
26、ep 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 in theanalysis of 6 % rare earth drier
27、s, 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 is easier to volatilize the solvent t
28、han 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 the beginning of the digestionbecause i
29、t 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 a tendency to bump which may beavoide
30、d 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 fritted-glass filter, rinseflask and
31、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 titrate with 0.01 M ferrous ammonium sulf
32、ate until theyellow color is barely perceptible. Add 1 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 ammoniu
33、m sulfate solution, mL,M2= molarity of ferrous ammonium sulfate solution,14.0 = millimolar weight of cerium 3 100, andS = weight of specimen used, g.11. Precision711.1 The precision estimates are based on an interlaboratorystudy in which one operator in seven different laboratoriesanalyzed in duplic
34、ate on two different days samples of ceriumand rare earth driers containing 6 and 3 % cerium. Both were6The sole source of supply of reagent grade sodium bismuthate, known to thecommittee at this time is Mallinckrodt Co. If you are aware of alternative suppliers,please provide this information to AS
35、TM International Headquarters. Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.7Supporting data are available from ASTM International Headquarters. RequestRR:D01-1032.D3970052commercially supplied drier solutions. The results
36、 were ana-lyzed statistically in accordance with Practice E 180 and afterdeletion of one laboratorys results the within-laboratory coef-ficient of variation was found to be 0.75 % relative at 12 df andthe between-laboratory coefficient of variation was 2.63 %relative at 10 df. Based on these coeffic
37、ients, 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 same operator on differentdays, should be considered suspect if they differ by more than2.3 %
38、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 % relative.12. Bias12.1 Bias cannot be determined for this method becausethere are no accepted standard
39、s 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 patent rights asserted in connection with any item mentionedin this standard. Users of this standard
40、 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 responsible technical committee and must be reviewed every five years andif n
41、ot 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 consideration at a meeting of theresponsible technical committee, which
42、 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 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).D3970053
