1、Designation: C560 15 An American National StandardStandard Test Methods forChemical Analysis of Graphite1This standard is issued under the fixed designation C560; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods cover the chemical analysis ofgraphite.1.2 The analytical procedures appear in the following order:Section
3、sSilicon 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-Quinizarin Sulfonic Acid Test Method 29 to 35Titanium by the Peroxide (Colorimetric) Test Me
4、thod 36 to 43Vanadium by the 3,3-Dimethylnaphthidine (Colorimetric)Test Method44 to 51Boron by the Curcumin-Oxalic Acid (Colorimetric) Test Method 52 to 591.3 The preferred concentration of sought element in thefinal solution, the limits of sensitivity, and the precision of theresults are given in T
5、able 1.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establi
6、sh 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:2C561 Test Method for Ash in a Graphite SampleD1193 Specification for Reagent WaterE29 Practice for Us
7、ing Significant Digits in Test Data toDetermine Conformance with Specifications3. Terminology3.1 Definitions:3.1.1 calibration curve, ngraphical or mathematical rep-resentation of the relationship between known concentrationsof an element in a series of standard calibration solutions andthe measured
8、 response from the measurement system.3.1.2 calibration solutions, nsolutions of accuratelyknown concentrations of the chemical element to be deter-mined using the calibration curve method.3.1.3 colorimetric analysis, nphotometric analysismethod of using absorption of monochromatic light in thevisib
9、le spectrum.3.1.4 photometric analysis, nanalytical chemistry methodfor quantitative chemical analysis based on the relationshipbetween solution concentrations and the absorption of mono-chromatic light, as expressed by the Beer law.4. Significance and Use4.1 These test methods provide a practical w
10、ay to measurethe concentration of certain trace elements in graphite. Manyend uses of graphite require that it be free of elements whichmay be incompatible with certain nuclear applications. Otherelemental contamination can affect the rate of oxidative deg-radation.4.2 These test methods allow measu
11、rement of trace amountsof contaminants with a minimal amount of costly equipment.The colorimetric procedures used are accessible to mostlaboratories.4.3 Other instrumental analysis techniques are available,capable of simultaneous quantitative analysis of 76 stableelements in a single run, with detec
12、tability limits in the partsper million range. Standards are currently being developed forelemental analysis of impurities in graphite using glow dis-charge mass spectrometry (GDMS), inductively coupledplasma optical emission spectroscopy (ICP-OES), combustionion chromatography (CIC).5. Reagents5.1
13、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,1These test methods are under the jurisdiction of ASTM Commit
14、tee D02 onPetroleum Products and Lubricants and are the direct responsibility of Subcommit-tee D02.F0 on Petroleum Products, Liquid Fuels, and LubricantsCurrent edition approved Oct. 1, 2015. Published November 2015. Originallyapproved in 1965. Last previous edition approved in 2010 as C560 88 (2010
15、)1.DOI: 10.1520/C0560-15.2For 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.*A Summary of Changes section appear
16、s at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit i
17、ts use without lessening theaccuracy of the determination.5.2 When available, National Institute of Standards andTechnology (NIST) certified reagents should be used as stan-dards in preparing calibration curves.5.3 Unless otherwise indicated, references to water shall beunderstood to mean reagent wa
18、ter conforming to SpecificationD1193.5.4 National Institute of Standards and Technology certifiedreagents 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.6. Sampling6.1 The entire sa
19、mple of graphite should be crushed andground to pass a No. 60 (250 m) sieve in a roll crusher. Thesample may have been reduced in size initially by drilling thetest bar with silicon carbide-tipped drills.NOTE 1The 75 g to 250 g graphite should be crushed and ground topass the 250 m sieve, before com
20、bustion, which will eventually result in75 g ash as needed in 13.1.7. Rounding Calculated Values7.1 Calculated values shall be rounded to the desired num-ber of places in accordance with Practice E29.8. Precision and Bias8.1 No statement is being made about either the precision orbias of these test
21、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.8.2 The relative reproducibility data in Table 1 has nosupportive resea
22、rch report on file and does not conform toASTM precision and bias standards.SILICON BY THE MOLYBDENUM BLUE TESTMETHOD9. Summary of Test Method9.1 Silicomolybdic acid is formed by adding ammoniummolybdate to soluble silicates in acid solution. The heteropolyacid is reduced with stannous chloride to f
23、orm a deep bluecolloidal solution. Photometric measurement is made at765 nm. Regular classical gravimetric methods for silica usingsodium carbonate fusion followed by hydrofluoric acid vola-tilization may be suitable for use.10. Stability of Color10.1 The blue colored solution should be disposed of
24、andthe determination repeated if a period of 12 h has elapsedbetween color development and measurements.11. Interferences11.1 There is no interference from the ions usually presentin graphite.12. Reagents12.1 Ammonium Molybdate (50 g/L)Dissolve 50 g ofammonium molybdate (NH4)6-Mo7O244H2O) in water a
25、nddilute to 1 L.12.2 Hydrochloric Acid (HCl) (1+1)Mix equal volumesof concentrated HCl, sp gr 1.19 and water.12.3 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. Store in a polyethylene bottle.Determine exact
26、 concentration by the standard gravimetricprocedure.12.4 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.12.5 Sodium Carbonate Solution (100 g L)Dissolve100 g of sodium carbonate (Na2C
27、O3) in water and dilute to 1 L.Store in a polyethylene bottle.12.6 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.12.7 Sulfuric Acid (H2SO4) (1+3)Carefully m
28、ix 1 volumeof concentrated H2SO4, sp gr 1.84 with 3 volumes of water.13. Preparation of Calibration Curve13.1 Calibration SolutionsTransfer 0 mL, 1.0 mL,3.0 mL, 5.0 mL, 7.0 mL, and 10 mL of silicon working solu-tion (1 mL = 0.01 mg Si) to 100 mL volumetric flasks. Add 5drops of H2SO4(1+3) and dilute
29、 to approximately 10 mL.3Reagent 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
30、United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.TABLE 1 Concentration of Elements, Limits of Sensitivity, andReproducibilityElementConcentrationRange, g/mLSolutionSensitivity Limit,g/mL SolutionReproducibility,Relative, %(/x 100)Silicon 10
31、g 100 mL to 100 g/100 mL1 g/100 mL 4Iron 100 g 100 mL to 600g/100 mL40 g/100 mL 5Calcium 600 g 100 mL to 3000g/100 mL50 g/100 mL 5Aluminum 10 g 100 mL to 100 g/100 mL2 g/100 mL 0.1Titanium 600 g 100 mL to 3000g/100 mL200 g/100 mL 2Vanadium 10 g 50 mL to 130 g/50mL5 g/50 mL 5Boron 0.5 g 50 mL to 1.4
32、g/50mL0.1 g/50 mL 20C560 15213.2 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.13.3 PhotometryTransfer a suitable portion of the reagentblank solutio
33、n 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.13.4 Calibration CurvePlot the photometric readings (ab-sorbance) of the calibration sol
34、ution against micrograms ofsilicon per 100 mL of solution.14. Procedure for Carbonate Fusion14.1 Sample SolutionRinse the ash (from a 50 g to 75 gash sample) from the platinum dish into a mullite mortar withthree 0.5 g portions of Na2CO3passing a No. 100 (150 m)sieve (see Test Method C561). Grind th
35、e resulting mixture topass a No. 200 (75 m) sieve to ensure intimate contact of theash with the flux. Then transfer the mixture to a platinumcrucible (containing 0.5 g of Na2CO3) with three 0.5 g rinses ofNa2CO3. Add sufficient Na2CO3to bring the total Na2CO3content to 6 g. Cover the crucible, and f
36、use gently over abunsen burner.NOTE 2In order to get 75 g ash, one needs to combust 250 kg highpuruty graphite (300 ppm ash) or 75 kg low purity graphite (1000 ppmash).14.1.1 When fusion is complete (usually 30 min to 1 h),remove the crucible from the burner, swirl to distribute the melton the sides
37、 of the crucible, and allow to cool. Then place thecrucible and contents in a 200 mL high-form beaker and add25 mL 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.1
38、4.1.2 Transfer to a 100 mL volumetric flask, dilute tovolume, and mix. Transfer a suitable aliquot of this solution toa 100 mL volumetric flask.14.2 Color DevelopmentAdjust the pH of the aliquot to 6to 8 with Na2CO3solution, then proceed in accordance with14.2.14.3 PhotometryProceed in accordance wi
39、th 13.3.14.4 CalibrationConvert the photometric reading of thesample solution to micrograms of silicon by means of thecalibration curve.15. Calculation15.1 Calculate the parts per million (ppm) of silicon in theoriginal sample as follows:Silicon, ppm A 3B!/Wwhere:A = silicon per 100 mL of solution f
40、ound in the aliquotused, g,B = aliquot factor = original volume divided by aliquottaken for analysis, andW = original sample weight, g.IRON BY THE ORTHO-PHENANTHROLINE(PHOTOMETRIC) TEST METHOD16. Summary of Test Method16.1 After suitable dilution of an aliquot from the carbonatefusion is adjusted to
41、 a pH of 3.0, the iron is reduced withhydroxylamine hydrochloride. The ferrous ortho-phenanthroline complex is formed, and its absorption is mea-sured at a wavelength of 490 nm.17. Stability of Color17.1 The color becomes stable within 15 min and does notchange for at least 48 h.18. Interferences18.
42、1 No interfering elements are normally present in graph-ite.19. Reagents19.1 Ammonium Hydroxide (NH4OH) (1+1)Mix equalvolumes of concentrated NH4OH, sp gr 0.90 and water.19.2 Bromine WaterAdd 10 mL of bromine to 1 L ofwater. Allow to stand for 24 h.19.3 Hydrochloric Acid (HCl) (1+1)Mix equal volumes
43、of concentrated HCl, sp gr 1.19 and water.19.4 Hydroxylamine Hydrochloride SolutionDissolve10 g of hydroxylamine hydrochloride (NH2OHHCl) in waterand dilute to 100 mL. Discard the solution if color develops onstanding for long periods of time.19.5 Iron, Standard Solution (1 mL = 0.1 mg Fe)Into a100
44、mL beaker, weigh 0.1000 g of iron wire. Dissolve the wirein 50 mL of HCl (1+1). Add 1 mL of bromine water to oxidizethe iron to the ferric state. Boil the solution to expel the excessbromine and dilute to 1 L in a volumetric flask.19.6 Iron Wire, primary standard, over 99.9 % pure.19.7 o-Phenanthrol
45、ineDissolve 2 g of 1,10-phenanthroline in ethyl alcohol and dilute to 250 mL with ethylalcohol in a volumetric flask. Discard this solution if colordevelops upon long standing.20. Preparation of Calibration Curve20.1 Calibration SolutionsTransfer 0.0, mL 1.0 mL,2.0 mL, 3.0 mL, 4.0 mL, 5.0 mL, and 6.
46、0 mL of iron solution(1 mL = 0.1 mg Fe) to 100 mL volumetric flasks. Add NH4OH(1+1) until the brown hydrous precipitate of ferric hydroxide(Fe(OH)3) is just visible. Then add HCl (1+1) drop-wise, whilestirring, until the precipitate just dissolves. Bring the pH of thesolution to 3.0 by adding 2 addi
47、tional drops of HCl (1+1). Thenadd 2 mL of NH2OHHCl solution.20.2 Color DevelopmentHeat the solutions in the flasksalmost to boiling. Add 1 mL of o-phenanthroline solution andallow the solutions to cool. Then dilute to the mark with water.20.3 PhotometryTransfer a suitable portion of the reagentblan
48、k solution to a 1 cm absorption cell, and adjust theC560 153spectrophotometer to the initial setting using a wavelength of490 nm. While maintaining this photometer adjustment, takethe photometric readings of the calibration solutions.20.4 Calibration CurvePlot the absorbance of the calibra-tion solu
49、tion against micrograms of iron per 100 mL ofsolution.21. Procedure21.1 Sample SolutionProceed in accordance with 14.1.21.2 Color DevelopmentProceed in accordance with 20.2.21.3 PhotometryProceed in accordance with 20.2.21.4 CalibrationConvert the photometric reading of thesample solution to micrograms of iron by means of thecalibration curve.22. Calculation22.1 Calculate the ppm of iron in the original sample asfollows:Fe, ppm A 3B!/Wwhere:A = iron per 100 mL of solution in the aliq
