1、Designation: D50 90 (Reapproved 2011)Standard Test Methods forChemical Analysis of Yellow, Orange, Red, and BrownPigments Containing Iron and Manganese1This standard is issued under the fixed designation D50; the number immediately following the designation indicates the year of originaladoption or,
2、 in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () 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. Scope1.1
3、 These test methods cover procedures for the chemicalanalysis of yellow, orange, red, and brown pigments containingiron and manganese. The test methods apply specifically to thefollowing pigments: synthetic hydrated yellow iron oxide,yellow ocher, red and brown iron oxides, raw and burnt umber,raw a
4、nd burnt sienna, and venetian red.1.2 The analytical procedures appear in the following order:ASTMMethodRefer-Dry Pigments Sections encesMoisture and Other Volatile Matter 6 D280Loss on Ignition 7Coarse Particles 8 D185Matter Soluble in Water 9 D1208Organic Coloring Matter 10Iron Oxide 11 and 12Calc
5、ium Compounds (Reported as CaO) 13 and 14Sulfates Soluble in Hydrochloric Acid 15 and 16Lead Chromate (in Ochers) 17Calcium Carbonate (in Venetian Red) 18 C25Manganese (in Siennas and Umbers) 19 and 20Pigment Pastes in OilPigment Content 21 D1208Moisture and Other Volatile Matter 22 D1208Nonvolatile
6、 Matter in Vehicle 23Moisture by Distillation 24 D1208Coarse Particles and Skins 25 D185Consistency (Stormer) 26 D5621.3 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 thesaf
7、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:2C25 Test Methods for Chemical A
8、nalysis of Limestone,Quicklime, and Hydrated LimeD185 Test Methods for Coarse Particles in PigmentsD280 Test Methods for Hygroscopic Moisture (and OtherMatter Volatile Under the Test Conditions) in PigmentsD562 Test Method for Consistency of Paints MeasuringKrebs Unit (KU) Viscosity Using a Stormer-
9、Type Viscom-eterD1193 Specification for Reagent WaterD1208 Test Methods for Common Properties of CertainPigmentsE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Significance and Use3.1 These test methods compile in one place, recommendedprocedures for analyzing inorganic colored pi
10、gments. Thesepigments are used extensively in paints, and for this reasontheir compositions are important to the formulators and user.4. Preparation of Sample4.1 Mix the sample thoroughly and take a representativeportion for analysis. Reduce any lumps or coarse particles to afine powder by grinding.
11、 Grind extracted pigments to pass aNo. 80 (180-m) sieve (see Specification E11 for detailed1These test methods are 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.
12、Current edition approved June 1, 2011. Published June 2011. Originallyapproved in 1917. Last previous edition approved in 2005 as D50 90 (2005). DOI:10.1520/D0050-90R11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annua
13、l Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.requirements). Discard any skins that do not pass through thesieve. Mix the f
14、inely ground pigment thoroughly.5. Purity of Reagents5.1 Purity of ReagentsUnless otherwise indicated, it isintended that all reagents shall conform to the specifications ofthe Committee onAnalytical Reagents of theAmerican Chemi-cal Society, where such specifications are available.3Othergrades may
15、be used, provided it is first ascertained that thereagent is of sufficiently high purity to permit its use withoutlessening the accuracy of the determination.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean Type II reagent waterconforming to Specification
16、 D1193.DRY PIGMENTSMoisture and Other Volatile Matter6. Procedure6.1 Determine moisture and other volatile matter in accor-dance with Method A of Test Methods D280.Loss on Ignition7. Procedure7.1 Weigh accurately approximately1gofpigment into apreviously weighed and ignited porcelain crucible (Note
17、1).Cover and ignite to constant weight over a bunsen or Mekerburner or in an electric furnace at a temperature of approxi-mately 900C. Cool in a desiccator, weigh, and calculate thepercent loss on ignition. This figure may include combinedwater, carbon dioxide (CO2), organic matter, and some sulfuri
18、coxide (SO3) if much calcium sulfate (CaSO4) is present. TheCO2may be determined on a separate portion if desired.NOTE 1It is inadvisable to use platinum unless it is known thatattacking substances are absent.Coarse Particles8. Procedure8.1 Determine coarse particles in accordance with TestMethods D
19、185.Matter Soluble in Water9. Procedure9.1 Determine matter soluble in water in accordance withTest Methods D1208.Organic Coloring Matter10. Procedure10.1 Boil2gofthesample with 25 mL of water, let settle,and decant the supernatant liquid. Boil the residue with 25 mLof ethyl alcohol (95 %) and decan
20、t as before. Boil the residuewith 25 mL of 1 N alcoholic sodium hydroxide (NaOH)solution and again decant. Boil another 2-g portion of thesample with 25 mL of chloroform, let settle, and decant thesupernatant liquid. If any one of the above solutions is colored,organic coloring matter is indicated (
21、Note 2). If the solutionsremain colorless, organic colors are probably absent, but maybe tested for by reference to procedures given in standardreference works, taking into account the nature of the pigmentinvolved.4NOTE 2With this class of pigments indication of presence of anorganic color may ofte
22、n be noted by the characteristic odor given off onignition.Iron Oxide11. Reagents11.1 Stannous Chloride Solution (SnCl22H2O)Dissolve50 g of SnCl22H2O in 300 mL of hydrochloric acid (HCl) (spgr 1.19) and dilute with water to 500 mL. Keep the clearsolution in a tightly stoppered bottle containing some
23、 metallictin.11.2 Mercuric Chloride Solution (HgCl2)Prepare a satu-rated solution of HgCl2(60 to 100 g/L).11.3 Sulfuric-Phosphoric Acid MixtureMix 150 mL ofsulfuric acid (H2SO4) (sp gr 1.84) with 150 mL of phosphoricacid (H3PO4) (85 %) and dilute with water to 1 L.11.4 Diphenylamine IndicatorDissolv
24、e1gofdiphe-nylamine in 100 mL of H2SO4(sp gr 1.84).11.5 Standard Potassium Dichromate Solution(K2Cr2O7)(0.1 N)Dissolve 4.904 g of K2Cr2O7in water and dilute to 1L. Standardize against the National Institute of Standards andTechnology standard sample No. 27 of Sibley iron ore.11.6 Potassium Ferricyan
25、ide Solution (K3Fe(CN)6)Optional. Dissolve approximately 0.01 g of K3Fe(CN)6in 50mL of water. This solution must be made fresh when wantedbecause it does not keep.12. Procedure12.1 According to the amount of iron in the pigment, weigh0.3 to 1.0 g of the pigment and ignite in a porcelain crucible ata
26、 dull red heat to destroy organic matter. Transfer to a 400-mLbeaker and add 25 mL of HCl (sp gr 1.19). Cover with awatchglass and digest just short of boiling (80 to 90C) until nodark specks can be seen in the insoluble residue. The additionof a few drops of SnCl2solution after adding the acid grea
27、tlyassists dissolving of the iron. When the residue is light in color,the solution of iron may be considered complete. This may takefrom 15 min to 1 h, or longer.12.2 Add 25 to 50 mL of water and heat to gentle boiling(avoid vigorous prolonged boiling). Slowly add SnCl2solutiondropwise until the las
28、t drop makes the solution colorless or freefrom any tinge of yellow, then add 1 or 2 drops in excess. It isbest to keep the watchglass on the beaker while adding theSnCl2solution, with agitation of the hot iron solution after eachaddition. If too much SnCl2is added by mistake, add potassium3Reagent
29、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., and the United States Pharmacopeiaand Nat
30、ional Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.4Reference may be made to the following: Payne, H. F., “Organic CoatingsTechnology,” Vol II, John Wiley then add all at once with vigorousstirring 15 mL of HgCl2solution. Let stand 3 to 4 min. A slightwhite precipitate should
31、form. If none, or a heavy grayishprecipitate forms, the determination should be discarded andrepeated.12.3 Add 15 mL of H2SO4-H3PO4mixture and 3 drops ofdiphenylamine indicator solution. Titrate with K2Cr2O7solu-tion, taking the sudden change of the dark green color to ablue-black color as the end p
32、oint.12.4 If preferred, K3Fe(CN)6may be used as an externalindicator. In this case omit the addition of the H2SO4-H3PO4mixture and the diphenylamine indicator. Titrate with theK2Cr2O7solution as in 12.3, except toward the end take out avery small drop of the solution being titrated and touch this to
33、a drop of the K3Fe(CN)6solution, best placed on a paraffinedsurface. Toward the end point the blue is replaced by abluish-green coloration, perceptible at the junction of the twosolutions. Take as the end point when no trace of the bluish-green coloration can be detected.12.5 CalculationCalculate th
34、e percent of iron oxide(Fe2O3), A, as follows:A 5 FV/S! 3 100 (1)where:F =Fe2O3equivalent of the K2Cr2O7solution, g/mL,V =K2Cr2O7solution required, mL, andS = sample used, g.Calcium Compounds (Reported as CaO)13. Reagents13.1 Ammonium Oxalate Saturated SolutionHeat to boil-ing 5 g powdered ammonium
35、oxalate (NH4)2C2O4H2O and100 mL of water. Allow to cool.13.2 Hydrogen Peroxide (H2O2) (30 %).13.3 Potassium Permanganate, Standard Solution(KMnO4) (0.1 N)Dissolve 3.16 g of KMnO4in water anddilute to 1 L. Let stand 8 to 14 days, siphon off the clearsolution (or filter through a medium-porosity fritt
36、ed disk), andstandardize against the National Institute of Standards andTechnology (NIST) standard sample No. 40 of sodium oxalate(Na2C2O4) as follows: In a 400-mL beaker dissolve 0.2500 to0.3000 g of the NIST Na2C2O4in 250 mL of hot water (80 to90C) and add 15 mL of H2SO4(1 + 1). Titrate at once wi
37、thKMnO4solution, stirring the liquid vigorously and continu-ously. The KMnO4must not be added more rapidly than 10 to15 mL/min, and the last 0.5 to 1 mL must be added dropwisewith particular care to allow each drop to be fully decolorizedbefore the next is introduced. The solution shall not be below
38、60C by the time the end point has been reached. (More rapidcooling may be prevented by allowing the beaker to stand ona small hot plate during the titration.) The use of a smallthermometer (nonmercury type) as a stirring rod is mostconvenient. Keep the KMnO4solution in a glass-stopperedbottle painte
39、d black to keep out light, or in a brown glass bottlestored in a dark place.13.4 Calculate the calcium oxide (CaO) value of the solu-tion as follows:C 5 W13 V1! 3 0.4185 (2)where:C = CaO equivalent of the KMnO4solution, g/mL,W1= sodium oxalate used, g, andV1= KMnO4solution required for the titration
40、, mL.0.4185 5 CaO/Na2C2O45 56.08 / 134.01 (3)14. Procedure14.1 Weigh 2.5 g of sample, transfer to a porcelain crucible,and ignite at a dull red heat to destroy organic matter. Cool,transfer to a 600-mL beaker, and add 100 mL of HCl (1 + 1).Digest just short of boiling until no dark specks can be see
41、n inthe insoluble residue. Add ammonium hydroxide (NH4OH) (spgr 0.90) in slight excess and about 2 mL of H2O2(30 %). Cool,transfer to a 500-mL graduated flask, and dilute to 500 mL.Mix thoroughly and filter through a dry paper.14.2 Take 100 mL of the filtrate (corresponding to 0.5 g ofsample), add a
42、 few drops of NH4OH, heat to boiling, and addan excess of saturated ammonium oxalate solution. Continuethe boiling until the precipitate becomes granular. Let standabout 30 min, filter, and wash three times with 20-mL aliquotsof hot water until free of ammonium oxalate.14.3 Place the beaker in which
43、 precipitation was madeunder the funnel, pierce the apex of the filter with a stirring rod,and wash the precipitate into the beaker with hot water. Pourwarm H2SO4(1 + 4) through the paper and wash a few times.Add about 30 mLof H2SO4(1 + 4) and dilute to about 250 mL.Heat to 90C and titrate at once w
44、ith KMnO4solution. (Thetemperature of the solution should not be below 60C when theend point is reached.)14.4 CalculationCalculate the percent of calcium com-pounds, A, in terms of CaO, as follows:A 5 V2C/0.5! 3 100 (4)where:V2= KMnO4solution required by the specimen, mL, andC = CaO equivalent of th
45、e KMnO4solution, g/mL.Sulfates Soluble in Hydrochloric Acid15. Reagent15.1 Barium Chloride SolutionDissolve 117 g of bariumchloride (BaCl22H2O) in water and dilute to 1 L.16. Procedure16.1 Weigh1gofthesample and add 30 mL of HCl (sp gr1.19). Boil 10 min, add about 50 mL of water, boil, filter, andwa
46、sh with hot water. Heat the solution to boiling, add NH4OHin excess, filter, and wash the precipitate several times with hotwater. Dissolve the precipitate in hot HCl (1 + 1), reprecipitatewith NH4OH, and wash well with hot water.16.2 Combine the united filtrates and make distinctly acidwith HCl, bo
47、il, and add dropwise, while stirring, an excess ofBaCl2solution. Boil about 10 min. The BaSO4precipitateshould normally stand for 2 to 4 h before filtering in order tocoagulate the precipitate. If the pad is thick enough on theD50 90 (2011)3Gooch crucible and filtrate is free of sulfate, then standi
48、ng maynot be necessary. Filter on a Gooch crucible, and wash with hotwater. Ignite at 900C, and weigh as barium sulfate (BaSO4).16.3 CalculationCalculate the percent of SO3, A,asfollows:A 5 P 3 0.343!/S 3 100 (5)where:P = weight of BaSO4,g,andS = weight of original sample, g.0.343 = SO3/BaSO4= 80.06
49、/233.42Lead Chromate (in Ochers)17. Procedure17.1 Test for lead by any standard method of qualitativeanalysis. The following method is suggested: Dissolve a smallportion of the pigment in cold nitric acid (HNO3) (1 + 5),stirring vigorously. Add a few millilitres of potassium iodide(KI) solution (100 g/L). The appearance of yellow crystalsindicates the presence of lead.Calcium Carbonate (in Venetian Red)18. Procedure18.1 Determine carbon dioxide (CO2) in accordance withTest Methods C25.18.2 CalculationCalculate the percent of calcium carbon-ate
