1、Designation: D126 87 (Reapproved 2012)Standard Test Methods forAnalysis of Yellow, Orange, and Green Pigments ContainingLead Chromate and Chromium Oxide Green1This standard is issued under the fixed designation D126; the number immediately following the designation indicates the year oforiginal adop
2、tion or, in the case of 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 Department of Defense.1.
3、Scope1.1 These test methods cover procedures for the chemicalanalysis of yellow, orange, and green pigments containing leadchromate and chromium oxide green.1.2 The analytical procedures appear in the following order:SectionsCHROME YELLOW,CHROME ORANGE, AND MOLYBDATE ORANGEORGANIC COLORS AND LAKES 7
4、MOISTURE AND OTHER VOLATILE MATTER 8MATTER SOLUBLE IN WATER 9LEAD CHROMATE 10 AND 11TOTAL LEAD 12SULFATE 13 AND 14CARBON DIOXIDE 15MOLYBDENUM 16 AND 17EXTENDERS 18-22Calculation of Substances Other than Insoluble LeadCompounds 23 and 24PURE CHROME GREEN AND REDUCED CHROME GREENORGANIC COLORS AND LAK
5、ES 25MOISTURE AND OTHER VOLATILE MATTER 26MATTER SOLUBLE IN WATER 27IRON BLUE 28LEAD CHROMATE 29 AND 30BARIUM SULFATE AND INSOLUBLE SILICEOUS MATERIAL 31TOTAL LEAD 32SULFATE 33CALCIUM OXIDE SOLUBLE IN ACID 34 AND 35EXTENDERS 36CALCULATION OF INSOLUBLE LEAD COMPOUNDS37CHROMIUM OXIDE GREENORGANIC COLO
6、RS AND LAKES 38MOISTURE AND OTHER VOLATILE MATTER 39MATTER SOLUBLE IN WATER 40TOTAL CHROMIUM AS CHROMIUM OXIDE 411.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety
7、problems, 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. Specific hazardstatements are given in Note 3.2. Referenced Documents2.1 ASTM
8、 Standards:2D280 Test Methods for Hygroscopic Moisture (and OtherMatter Volatile Under the Test Conditions) in PigmentsD521 Test Methods for Chemical Analysis of Zinc Dust(Metallic Zinc Powder)D1013 Test Method for Determining Total Nitrogen inResins and Plastics (Withdrawn 2007)3D1193 Specification
9、 for Reagent WaterE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Summary of Test Methods3.1 Chrome Yellow, Chrome Orange, and Molybdate Or-ange:3.1.1 Organic colors and lakes are determined qualitativelyby boiling the sample in water, then ethyl alcohol, and finallychloroform.3.1
10、.2 Moisture and other volatile matter are determined inaccordance with Test Method A of Test Methods D280.3.1.3 Matter soluble in water is determined by boiling inwater and filtering.3.1.4 Lead chromate is determined by dissolving the samplein dilute HCl, filtering and titrating potentiometrically w
11、ithFeSO4solution after addition of HClO4.3.1.5 Total lead is determined by precipitation as leadsulfide solution with H2SO4and final precipitation as leadsulfate.3.1.6 Sulfate is determined by dissolving the sample inacetic acid, neutralizing with sodium carbonate, plus addition1These test methods a
12、re under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibility of Subcommittee D01.31 on Pigment Specifications.Current edition approved June 1, 2012. Published August 2012. Originallyapproved in 1922. Last previous edition
13、approved in 2006 as D126 87 (2006).DOI: 10.1520/D0126-87R12.2For 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.3
14、The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1of HCl to an aliquot followed by addition of BaCl2toprecipitate as barium sulfate.3.1.7 Carbon dioxide
15、is determined by evolution.3.1.8 Molybdenum is determined by precipitation as thesulfide, solution in HNO3and H2SO4, addition of NH4OH andH2SO4. The solution is reduced in a Jones reductor, collectedunder Fe2(SO4)3solution and titrated with KMnO4solution.3.1.9 Extenders are either:3.1.9.1 Calcium ca
16、rbonate, calcium sulfate, magnesium car-bonate or;(a) The compounds in 3.1.9.1 are determined qualitativelyby precipitation with ammonium solution.(b) If chromium is present, it is reduced and the lead saltsdissolved in dissolving solution. Hydroxides and hydrousoxides are precipitated by addition o
17、f HCl and NH4OH andfiltered. CaC2O4is precipitated with calcium oxalate solutionand filtered, ashed and weighed as CaO. Alternatively, theprecipitate is dissolved in H2SO4and titrated with KMnO4.Magnesium is determined on the filtrate from calcium deter-mination by precipitation as the phosphate wit
18、h ammoniumphosphate solution.3.2 Chromium Oxide Green:3.2.1 Organic colors and lakes are determined qualitativelyby boiling the sample in water, then ethyl alcohol, and finallycholoroform.3.2.2 Moisture and other volatile matter are determined inaccordance with Test Method A of Test Methods D280.3.2
19、.3 Matter soluble in water is determined by boiling inwater and filtering.3.2.4 Total chromium as chromium oxide is determined bydissolving the sample in dilute HCl, filtering and titratingpotentiometrically with FeSO4solution after addition ofHClO4.4. Significance and Use4.1 These test methods are
20、for analysis designed as an aid inquality of yellow, orange, and green pigments containing leadchromate and chromium oxide green. Some sections may beapplicable to analysis of these pigments when extracted fromwhole paints.5. Purity of Reagents and Water5.1 ReagentsUnless otherwise indicated, it is
21、intendedthat all reagents shall conform to the specifications of theCommittee on Analytical Reagents of the American ChemicalSociety, where such specifications are available.4Other gradesmay be used, provided it is first ascertained that the reagent isof sufficiently high purity to permit its use wi
22、thout lesseningthe accuracy of the determination.5.2 WaterUnless otherwise indicated, references to waterfor use in the preparation of reagents and in analyticalprocedures shall be understood to mean reagent water con-forming to Type II of Specification D1193.6. Preparation of Sample6.1 Mix the samp
23、le thoroughly and take a representativeportion for analysis. Reduce any lumps or coarse particles to afine powder by grinding. Grind extracted pigments to pass aNo. 80 (180-m) sieve (Note 1). Discard any skins that do notpass through the sieve. Thoroughly mix the finely groundpigment and preserve in
24、 stoppered and suitably identifiedbottles or containers.NOTE 1Detailed requirements for this sieve are given in SpecificationE11.6.2 Moisten the weighed portions of extracted pigmentswith a small amount of suitable wetting agent (Note 1) beforeadding reagents for analysis.NOTE 2A 0.1 % solution of s
25、odium dioctylsuccinosulfonate has beenfound satisfactory. (This material is sold under the trade name of AerosolOT.) Wetting agents containing mineral salts, sulfates, or sulfonates whichmay be hydrolyzed to sulfates, should be avoided; the use of alcohol isalso undesirable because of its tendency t
26、o reduce chromates.NOTE 3Warning: As the National Institute for Occupational Safetyand Health has stated that hexavalent chromium compounds are hazardousto health, care should be exercised in preparation of the sample. Thewearing of a respirator and rubber or synthetic gloves are recommended.If hexa
27、valent chromium materials come in contact with the skin, washthoroughly with soap and water.CHROME YELLOW, CHROME ORANGE, AND MOLYBDATE ORANGE(Primrose, Lemon, and Medium Yellows; Chrome Oranges; Lead Molybdate or Basic Lead Chromate; Molybdate Orange)ORGANIC COLORS AND LAKES7. Procedure7.1 Boil 2 g
28、 of the sample 2 min with 25 mL of water, letsettle, and decant the supernatant liquid. Similarly, boil theresidue with 25 mL of ethyl alcohol (absolute or 95 %) anddecant as before. Likewise boil with 25 mL of chloroform andagain decant. If any one of the above solutions is colored,organic colors a
29、re present. If all solutions remain colorless,organic colors are presumably absent. The presence of organiccolors resistant to the above reagents is unlikely, but may betested for by reference to procedures given in standard refer-ence works.54Reagent Chemicals, American Chemical Society, Specificat
30、ions, 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., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention
31、, Inc. (USPC), Rockville,MD.5Reference may be made to the following: Payne, H. F., “Organic CoatingsTechnology,” Vol II, John Wiley then add 5mL of HCl (sp gr 1.19) slowly, dilute to 500 mL, and pass arapid current of H2S into the solution until precipitation iscomplete. Settle, filter, and wash wit
32、h water containing H2S.12.2 Rinse the precipitate from the filter (Note 5) into abeaker containing 25 mL of HNO3(1+3) and boil until all PbShas dissolved. Add 10 mL of H2SO4(1+1) and evaporate tostrong fumes of SO3. Cool and add 50 mL of water and 50 mLof ethyl alcohol (95 %) (Note 6). Let stand 1 h
33、; then filter ona tarred Gooch crucible. Wash with ethyl alcohol (95 %), dry,ignite at 500 to 600C, and weigh as PbSO4.NOTE 5If a trace of sulfide remains on the paper, the stained portionof the paper may be separately treated with bromine water, the paperfiltered off, and the filtrate added to the
34、body of the solution.NOTE 6Any sulfur remaining from decomposition of the sulfides maybe mechanically removed as a globule of solidified sulfur at this point.SULFATE613. Reagents13.1 Barium Chloride SolutionDissolve 117 g of BaCl22H2O in water and dilute to 1 L.13.2 Dissolving SolutionSee 10.1.13.3
35、Sodium Carbonate Solution (saturated)Prepare asolution containing excess Na2CO3at laboratory temperature,and free of SO4. Decant the clear solution for use as required.14. Procedure14.1 Digest 1.25 g of the sample with 100 mL of dissolvingsolution at 100C for 5 min. Add 25 mL of glacial acetic acida
36、nd 15 mL of ethyl alcohol and heat gently for 10 min toreduce chromium, as indicated by the green color of thesolution. Cool. Neutralize with saturated Na2CO3solution andadd a slight excess. Transfer to a 250-mL volumetric flask,dilute to the mark with distilled water, and mix. Filter withoutwashing
37、 through a dry filter paper, discarding the first 10 to 15mL.14.2 Take a 200-mL aliquot of the filtrate, neutralize withHCl (1+1), and add 10 mL excess. Heat to boiling and boil for5 min. To the gently boiling solution, add 15 mL of BaCl2solution dropwise with constant stirring. Digest on a steambat
38、h for 2 h. Filter through an ignited tarred Gooch crucible,6Sections 23 and 24 under “Calculation of Substances Other than Insoluble LeadCompounds” should be read carefully before proceeding with the analyses describedin Sections 10 to 22.D126 87 (2012)3wash with HCl (1+99), and finally with hot wat
39、er. Dry at 105to 110C, ignite at 900C, and weigh.CARBON DIOXIDE615. Procedure15.1 Determine CO2by the evolution method on 2.5 g of thesample, using dilute HNO3free of NO or NO2and absorbingthe CO2in soda lime or in KOH solution.MOLYBDENUM616. Reagents16.1 Ferric Sulfate SolutionDissolve 20 g of Fe2(
40、SO4)3(NH4)2SO4 24H2O in 200 mL of water to which has beenadded 50 mL of H2SO4(sp gr 1.84) and 20 mL of H3PO4(85 %), and dilute to 1 L.16.2 Jones ReductorThe reductor shall contain at least a35-cm column of amalgamated zinc, prepared by shaking 20 to30-mesh zinc free of iron or carbon with HgCl2solut
41、ion (20g/L) in sufficient quantity to produce an amalgam containing 1to 5 % of mercury, and supported by a suitable inert pad ofasbestos, glass wool, or other inert material.16.3 Potassium Permanganate, Standard Solution (0.1 N)Dissolve 3.16 g of KMnO4in water and dilute to 1 L. Let stand8 to 14 day
42、s, siphon off the clear solution (or filter through amedium porosity fritted disk), and standardize against theNational Bureau of Standards standard sample No. 40 ofsodium oxalate (Na2C2O4) as follows: In a 400-mL beakerdissolve 0.2500 to 0.3000 g of the Bureau of Standards sodiumoxalate in 250 mL o
43、f hot water (80 to 90C) and add 15 mL ofH2SO4(1+1). Titrate at once with KMnO4solution, stirring theliquid vigorously and continuously. The KMnO4must not beadded more rapidly than 10 to 15 mL/min, and the last 0.5 to1 mL must be added dropwise with particular care to alloweach drop to be fully decol
44、orized before the next is introduced.The solution shall not be below 60C by the time the end pointhas been reached. (More rapid cooling may be prevented byallowing the beaker to stand on a small asbestos-covered hotplate during the titration. The use of a small thermometer(non-mercury type) as a sti
45、rring rod is most convenient.) Keepthe KMnO4solution in a glass-stoppered bottle painted blackto keep out light, or in a brown glass bottle stored in a darkplace.17. Procedure17.1 Dissolve1gofthesample as described in Section 11.Add 5 mL of ethyl alcohol (95 % or absolute) and boil untilchromium is
46、reduced. Filter if any insoluble residue is present,retaining the filtrate and washings. Add NH4OH (sp gr 0.90)cautiously until a faint precipitate begins to form, then add 15mL of H2SO4(sp gr 1.84) and dilute to 300 mL. Heat toboiling, pass in a rapid stream of H2S for 15 min, and dilutewith 300 mL
47、 of hot water. Pass in H2S for 10 min, boil for 3min, and cool. Pass in H2S for 10 min, and let stand at roomtemperature for 1 h. Filter and wash with H2SO4(1+99)saturated with H2S.17.2 Rinse the sulfide precipitate into the original beakerand add 20 mL of HNO3(sp gr 1.42) and 5 mL of H2SO4(spgr 1.8
48、4) (see Note 5). Cover and heat to fumes. Cool, add 10mL of HNO3(sp gr 1.42), and again fume. Repeat thisoperation if necessary until a light-colored solution is obtained.Wash the cover and inside of the beaker and fume again toremove all HNO3. Dilute to 200 mL and add NH4OH (1+4)until neutral; then
49、 add 10 mL of H2SO4(sp gr 1.84).17.3 Cool the solution and reduce by passing through aJones reductor at a rate not exceeding 100 mL/min, collectingthe effluent under 200 mL of Fe2(SO4)3solution. Titrate withKMnO4solution. A blank determination should also be made.EXTENDERS618. General Considerations18.1 Extenders fall into two groups, depending on theirsolubility or insolubility in the dissolving solution described inSection 10, as follows:A. Extenders Soluble in Dissolving SolutionCalcium sul-fate (gypsum), calcium carbonate (whiting), and magnesiumcarbonate
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