1、Designation: C 560 88 (Reapproved 2005)e1An American National StandardStandard Test Methods forChemical Analysis of Graphite1This standard is issued under the fixed designation C 560; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 the 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.e1NOTEReplaced the word “asbestos” in 25.7 editorially in August 2005.1. Scope1.1 These test methods cover the chemi
3、cal analysis ofgraphite.1.2 The analytical procedures appear in the following order:SectionsSilicon by the Molybdenum Blue (Colorimetric) Test Method 8 to 14Ironbytheo-Phenanthroline (Colorimetric) Test Method 15 to 21Calcium by the Permanganate (Colorimetric) Test Method 22 to 28Aluminum by the 2-Q
4、uinizarin Sulfonic Acid Test Method 29 to 35Titanium by the Peroxide (Colorimetric) Test Method 36 to 43Vanadium by the 3,38-Dimethylnaphthidine (Colorimetric) TestMethod 44 to 51Boron by the Curcumin-Oxalic Acid (Colorimetric) Test Method 52 to 591.3 The preferred concentration of sought element in
5、 thefinal solution, the limits of sensitivity, and the precision of theresults are given in Table 1.1.4 The values stated in SI units are to be regarded as thestandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of
6、 the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. See 56.1 forspecific caution statement.2. Referenced Documents2.1 ASTM Standards:2C 561 Test Method for Ash in a Graphite SampleD 1193 Specificati
7、on for Reagent WaterE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications3. Significance and Use3.1 These test methods provide a practical way to measurethe concentration of certain trace elements in graphite. Manyend uses of graphite require that it be f
8、ree of elements whichmay be incompatible with certain nuclear applications. Otherelemental contamination can affect the rate of oxidative deg-radation.3.2 These test methods allow measurement of trace amountsof contaminants with a minimal amount of costly equipment.The colorimetric procedures used a
9、re accessible to mostlaboratories.4. Reagents4.1 Purity 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 s
10、pecifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.4.2 When available, National Institute of Standards andTechnology (NIST) certified reagents shoul
11、d be used as stan-dards in preparing calibration curves.4.3 Unless otherwise indicated, references to water shall beunderstood to mean reagent water conforming to SpecificationD 1193.1These test methods are under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and are the
12、direct responsibility of Subcommit-tee D02.F0 on Manufactured Carbon and Graphite Products.Current edition approved May 1, 2005. Published May 2005. Originallyapproved in 1965. Last previous edition approved in 1998 as C 560 88 (1998).2For referenced ASTM standards, visit the ASTM website, www.astm.
13、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.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the
14、 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. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.TABLE 1 Concentration of Elements, Limits
15、of Sensitivity, andReproducibilityElementConcentrationRange, g/mLSolutionSensitivity Limit,g/mL SolutionReproducibility,Relative, %(s/x 3 100)Silicon 10 to 100 g/100 mL 1 g/100 mL 64Iron 100 to 600 g/100 mL 40 g/100 mL 65Calcium 600 to 3000 g/100 mL 50 g/100 mL 65Aluminum 10 to 100 g/100 mL 2 g/100
16、mL 60.1Titanium 600 to 3000 g/100 mL 200 g/100 mL 62Vanadium 10 to 130 g/50 mL 5 g/50 mL 65Boron 0.5 to 1.4 g/50 mL 0.1 g/50 mL 6201Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.4 National Institute of Standards and Technology cer
17、tifiedreagents specified in certain steps of this procedure may nolonger be available. If NIST reagents are not available, then thehighest purity reagent grade shall be substituted.5. Sampling5.1 The entire sample of graphite should be crushed andground to pass a No. 60 (250-m) sieve in a roll crush
18、er. Thesample may have been reduced in size initially by drilling thetest bar with silicon carbide-tipped drills.6. Rounding Calculated Values6.1 Calculated values shall be rounded to the desired num-ber of places in accordance with Practice E29.7. Precision and Bias7.1 No statement is being made ab
19、out either the precision orbias of these test methods. At this time Committee C05 isinvestigating new standard methods of chemical analysis ofgraphite that will eventually replace these test methods. Forthis reason, no statistical study of these test methods has beenplanned.7.2 The relative reproduc
20、ibility data in Table 1 has nosupportive research report on file and does not conform toASTM precision and bias standards.SILICON BY THE MOLYBDENUM BLUE TESTMETHOD8. Summary of Test Method8.1 Silicomolybdic acid is formed by adding ammoniummolybdate to soluble silicates in acid solution. The heterop
21、olyacid is reduced with stannous chloride to form a deep bluecolloidal solution. Photometric measurement is made at 765nm. Regular classical gravimetric methods for silica usingsodium carbonate fusion followed by hydrofluoric acid vola-tilization may be suitable for use.9. Stability of Color9.1 The
22、blue colored solution should be disposed of and thedetermination repeated if a period of 12 h has elapsed betweencolor development and measurements.10. Interferences10.1 There is no interference from the ions usually presentin graphite.11. Reagents11.1 Ammonium Molybdate (50 g/L)Dissolve 50 g ofammo
23、nium molybdate (NH4)6-Mo7O244H2O) in water anddilute to 1 L.11.2 Hydrochloric Acid (HCl) (1+1)Mix equal volumesof concentrated HCl, sp gr 1.19 and water.11.3 Silicon, Standard Solution (1 mL = 1 mg Si)Dissolve10.1 g of sodium silicate (Na2SiO39H2O) in water and diluteto 1 L in a volumetric flask. St
24、ore in a polyethylene bottle.Determine exact concentration by the standard gravimetricprocedure.11.4 Silicon, Working Solution (1 mL = 0.01 mg Si)Dilute10 mL of standard silicon solution (1 mL = mg Si) to 1 L in avolumetric flask. Transfer to a polyethylene bottle.11.5 Sodium Carbonate Solution (100
25、 g/L)Dissolve 100 gof sodium carbonate (Na2CO3) in water and dilute to 1 L. Storein a polyethylene bottle.11.6 Stannous Chloride SolutionDissolve 2.5 g of stan-nous chloride (SnCl22H2O) in 5 mL of hot concentrated HCl(sp gr 1.19) and dilute to 250 mL with water. Prepare a freshsolution every 2 weeks
26、.11.7 Sulfuric Acid (H2SO4) (1+3)Carefully mix 1 volumeof concentrated H2SO4, sp gr 1.84 with 3 volumes of water.12. Preparation of Calibration Curve12.1 Calibration SolutionsTransfer 0, 1.0, 3.0, 5.0, 7.0,and 10 mL of silicon working solution (1 mL = 0.01 mg Si) to100-mL volumetric flasks. Add 5 dr
27、ops of H2SO4(1+3) anddilute to approximately 10 mL.12.2 Color DevelopmentAdd 2.5 mL of (NH4)6Mo7O24solution to each flask and let stand 5 min. Then add 5.0 mL ofH2SO4(1+3), mix well, and add 5 drops of SnCl2solution.Dilute to volume and let stand 5 min.12.3 PhotometryTransfer a suitable portion of t
28、he reagentblank solution to a 1-cm absorption cell and adjust thephotometer to the initial setting, using a wavelength of 765 nm.While maintaining this photometer adjustment, take the pho-tometric readings of the calibration solutions.12.4 Calibration CurvePlot the photometric readings (ab-sorbance)
29、 of the calibration solution against micrograms ofsilicon per 100 mL of solution.13. Procedure for Carbonate Fusion13.1 Sample SolutionRinse the ash (from a 50 to 75-g ashsample) from the platinum dish into a mullite mortar with three0.5-g portions of Na2CO3passing a No. 100 (150-m) sieve(see Test M
30、ethod C 561). Grind the resulting mixture to pass aNo. 200 (75-m) sieve to ensure intimate contact of the ashwith the flux. Then transfer the mixture to a platinum crucible(containing 0.5 g of Na2CO3) with three 0.5-g rinses ofNa2CO3. Add sufficient Na2CO3to bring the total Na2CO3content to 6 g. Cov
31、er the crucible, and fuse gently over abunsen burner.13.1.1 When fusion is complete (usually 30 min to 1 h),remove the crucible from the burner, swirl to distribute the melton the sides of the crucible, and allow to cool. Then place thecrucible and contents in a 200-mL high-form beaker and add25 mL
32、of water. Cover the beaker with a watch glass, andcautiously add HCl (1+1) to decompose the melt. Whensolution of the melt is complete, boil for several minutes on ahot plate and cool.13.1.2 Transfer to a 100-mL volumetric flask, dilute tovolume, and mix. Transfer a suitable aliquot of this solution
33、 toa 100-mL volumetric flask.13.2 Color DevelopmentAdjust the pH of the aliquot to 6to 8 with Na2CO3solution, then proceed in accordance with13.2.13.3 PhotometryProceed in accordance with 12.3.C 560 88 (2005)e1213.4 CalibrationConvert the photometric reading of thesample solution to micrograms of si
34、licon by means of thecalibration curve.14. Calculation14.1 Calculate the parts per million (ppm) of silicon in theoriginal sample as follows:Silicon, ppm A 3 B!/Wwhere:A = silicon per 100 mL of solution found in the aliquotused, g,B = aliquot factor = original volume divided by aliquottaken for anal
35、ysis, andW = original sample weight, g.IRON BY THE ORTHO-PHENANTHROLINE(PHOTOMETRIC) TEST METHOD15. Summary of Test Method15.1 After suitable dilution of an aliquot from the carbonatefusion is adjusted to a pH of 3.0, the iron is reduced withhydroxylamine hydrochloride. The ferrous ortho-phenanthrol
36、ine complex is formed, and its absorption is mea-sured at a wavelength of 490 nm.16. Stability of Color16.1 The color becomes stable within 15 min and does notchange for at least 48 h.17. Interferences17.1 No interfering elements are normally present in graph-ite.18. Reagents18.1 Ammonium Hydroxide
37、(NH4OH) (1+1)Mix equalvolumes of concentrated NH4OH, sp gr 0.90 and water.18.2 Bromine WaterAdd 10 mL of bromine to 1 L ofwater. Allow to stand for 24 h.18.3 Hydrochloric Acid (HCl) (1+1)Mix equal volumesof concentrated HCl, sp gr 1.19 and water.18.4 Hydroxylamine Hydrochloride SolutionDissolve 10g
38、of hydroxylamine hydrochloride (NH2OHHCl) in water anddilute to 100 mL. Discard the solution if color develops onstanding for long periods of time.18.5 Iron, Standard Solution (1 mL = 0.1 mg Fe)Into a100-mL beaker, weigh 0.1000 g of iron wire. Dissolve the wirein 50 mL of HCl (1+1). Add 1 mL of brom
39、ine water to oxidizethe iron to the ferric state. Boil the solution to expel the excessbromine and dilute to 1 L in a volumetric flask.18.6 Iron Wire, primary standard, over 99.9 % pure.18.7 o-PhenanthrolineDissolve2gof1,10-phenanthroline in ethyl alcohol and dilute to 250 mL with ethylalcohol in a
40、volumetric flask. Discard this solution if colordevelops upon long standing.19. Preparation of Calibration Curve19.1 Calibration SolutionsTransfer 0.0, 1.0, 2.0, 3.0, 4.0,5.0, and 6.0 mL of iron solution (1 mL = 0.1 mg Fe) to 100-mLvolumetric flasks. Add NH4OH (1+1) until the brown hydrousprecipitat
41、e of ferric hydroxide (Fe(OH)3) is just visible. Thenadd HCl (1+1) drop-wise, while stirring, until the precipitatejust dissolves. Bring the pH of the solution to 3.0 by adding 2additional drops of HCl (1+1). Then add 2 mL of NH2OHHClsolution.19.2 Color DevelopmentHeat the solutions in the flasksalm
42、ost to boiling. Add 1 mL of o-phenanthroline solution andallow the solutions to cool. Then dilute to the mark with water.19.3 PhotometryTransfer a suitable portion of the reagentblank solution to a 1-cm absorption cell, and adjust thespectrophotometer to the initial setting using a wavelength of490
43、nm. While maintaining this photometer adjustment, takethe photometric readings of the calibration solutions.19.4 Calibration CurvePlot the absorbance of the calibra-tion solution against micrograms of iron per 100 mL ofsolution.20. Procedure20.1 Sample SolutionProceed in accordance with 13.1.20.2 Co
44、lor DevelopmentProceed in accordance with 19.2.20.3 PhotometryProceed in accordance with 19.2.20.4 CalibrationConvert the photometric reading of thesample solution to micrograms of iron by means of thecalibration curve.21. Calculation21.1 Calculate the ppm of iron in the original sample asfollows:Fe
45、, ppm A 3 B!/Wwhere:A = iron per 100 mL of solution in the aliquot used, g,B = aliquot factor = original volume divided by aliquottaken for analysis, andW = original sample weight, g.CALCIUM BY THE PERMANGANATE(COLORIMETRIC) TEST METHOD22. Summary of Test Method22.1 Calcium is precipitated as the ox
46、alate, filtered off, anddissolved in sulfuric acid. The acid solution is added to a dilutepotassium permanganate solution, and the decrease in absorp-tion is measured at a wavelength of 528 nm.23. Stability of Color23.1 Potassium permanganate solution is decomposed rap-idly by exposure to air or lig
47、ht. Photometric readings should bemade at once.24. Interferences24.1 Ashed graphite samples are normally free of significantconcentrations of possible interfering ions.25. Reagents25.1 Ammonium Hydroxide (NH4OH2) (1+6)Mix 1 vol-ume of concentrated NH4OH2, sp gr 0.90 with 6 volumes ofwater.C 560 88 (
48、2005)e1325.2 Ammonium Oxalate SolutionPrepare a saturated so-lution of ammonium oxalate (NH4)2C2O42H2O).25.3 Bromocresol Green Indicator SolutionUse the watersoluble sodium salt. Dissolve 0.040 g in water and dilute to 100mL. Store in a glass-stoppered brown bottle.25.4 Formate Buffer Solution (pH 3
49、.7)Dissolve 31.5 g ofammonium formate in about 200 mL of water and transfer to a1-L volumetric flask. Add 20.8 mL of formic acid, dilute tovolume, and mix well.25.5 Hydrochloric Acid (HCl) (1+1)Mix equal volumesof concentrated HCl, sp gr 1.19 and water.25.6 Oxalate, Standard Solution (1 mL = 0.125 mg Ca)Dry approximately2gofsodium oxalate (Na2C2O4) at 105Cfor 1 h, and cool in a desiccator. Weigh accurately 0.2090 g intoa 250-mL beaker, dissolve in boiled water, and dilute to 500mL in a volumetric flask.25.7 Potass
