ANSI ASTM C560-2015 Standard Test Methods for Chemical Analysis of Graphite.pdf

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1、Designation: C560 151An 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.1NOTESubsection 1.2 was corrected editorially in February 2017.1. Scope*1.1 These test methods cover the chemical analysis ofgraphite.1.2

3、The analytical procedures appear in the following order:SectionsSilicon by the Molybdenum Blue (Colorimetric) Test Method 9 to 15Ironbytheo-Phenanthroline (Colorimetric) Test Method 16 to 22Calcium by the Permanganate (Colorimetric) Test Method 23 to 29Aluminum by the 2-Quinizarin Sulfonic Acid Test

4、 Method 30 to 36Titanium by the Peroxide (Colorimetric) Test Method 37 to 44Vanadium by the 3,3-Dimethylnaphthidine (Colorimetric)Test Method45 to 52Boron by the Curcumin-Oxalic Acid (Colorimetric) Test Method 53 to 601.3 The preferred concentration of sought element in thefinal solution, the limits

5、 of sensitivity, and the precision of theresults are given in Table 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.

6、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. See 56.1 forspecific caution statement.2. Referenced Documents2.1 ASTM Standards:2C561 Test Method for Ash in a Graphite

7、 SampleD1193 Specification for Reagent WaterE29 Practice for Using 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 elemen

8、t in a series of standard calibration solutions andthe measured 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 analys

9、ismethod of using absorption of monochromatic light in thevisible 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. S

10、ignificance and Use4.1 These test methods provide a practical way to measurethe concentration of certain trace elements in graphite. Manyend uses of graphite require that it be free of elements whichmay be incompatible with certain nuclear applications. Otherelemental contamination can affect the ra

11、te of oxidative deg-radation.4.2 These test methods allow measurement 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 quantit

12、ative analysis of 76 stableelements in a single run, with detectability 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 spectroscop

13、y (ICP-OES), combustionion chromatography (CIC).5. Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended that1These test methods are under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and are the dire

14、ct 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)1.DOI: 10.1520/C0560-15E01.2For referenced ASTM standards,

15、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 appears at the end of this standardCopyright ASTM International

16、, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides a

17、nd Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1all reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused, provided

18、 it is first ascertained that the reagent is ofsufficiently high purity to permit its 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 Un

19、less otherwise indicated, references to water shall beunderstood to mean reagent water 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, the

20、n thehighest purity reagent grade shall be substituted.6. Sampling6.1 The entire sample 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

21、g to 250 g graphite should be crushed and ground topass the 250 m sieve, before combustion, 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

22、Bias8.1 No statement is being made about 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

23、beenplanned.8.2 The relative reproducibility data in Table 1 has nosupportive research 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 si

24、licates in acid solution. The heteropolyacid is reduced with stannous chloride to form 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

25、for use.10. Stability of Color10.1 The blue colored solution should be disposed of 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

26、 Molybdate (50 g/L)Dissolve 50 g ofammonium molybdate (NH4)6-Mo7O244H2O) in water anddilute 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

27、 diluteto 1 L in a volumetric flask. Store in a polyethylene bottle.Determine exact 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 bot

28、tle.12.5 Sodium Carbonate Solution (100 g L)Dissolve 100 gof sodium carbonate (Na2CO3) in water and dilute to 1 L. Storein 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

29、. Prepare a freshsolution every 2 weeks.12.7 Sulfuric Acid (H2SO4) (1+3)Carefully mix 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 (

30、1 mL = 0.01 mg Si) to 100 mL volumetric flasks. Add 5drops of H2SO4(1+3) and dilute 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, se

31、e 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 of Sensitivity, andReproducibilityElementConcentrationRange, g/mLSo

32、lutionSensitivity Limit,g/mL SolutionReproducibility,Relative, %(/x 100)Silicon 10 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 mL

33、200 g/100 mL 2Vanadium 10 g 50 mL to 130 g/50mL5 g/50 mL 5Boron 0.5 g 50 mL to 1.4 g/50mL0.1 g/50 mL 20C560 151213.2 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 le

34、t stand 5 min.13.3 PhotometryTransfer a suitable portion of the 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.13.4

35、 Calibration CurvePlot the photometric readings (ab-sorbance) of the calibration solution 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

36、 g portions of Na2CO3passing a No. 100 (150 m)sieve (see Test Method C561). Grind the 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

37、 sufficient Na2CO3to bring the total Na2CO3content to 6 g. Cover the crucible, and fuse 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 t

38、o 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 of water. Cover the beaker with a watch glass, andcautiously add HCl (1+1) to decompose the melt. Whe

39、nsolution of the melt is complete, boil for several minutes on ahot plate and cool.14.1.2 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 Na2CO3s

40、olution, then proceed in accordance with14.2.14.3 PhotometryProceed in accordance with 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 theorigi

41、nal sample as follows:Silicon, ppm A 3B!/Wwhere:A = silicon per 100 mL of solution found 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 Meth

42、od16.1 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-phenanthroline complex is formed, and its absorption is mea-sured at a wavelength of 490 nm.17. Stability of Color17.1 The color be

43、comes stable within 15 min and does notchange for at least 48 h.18. Interferences18.1 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

44、ofwater. Allow to stand for 24 h.19.3 Hydrochloric Acid (HCl) (1+1)Mix equal volumesof 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 onstandin

45、g for long periods of time.19.5 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 bromine water to oxidizethe iron to the ferric state. Boil the solution to expel the excessbromine and dilute to 1 L in a vo

46、lumetric flask.19.6 Iron Wire, primary standard, over 99.9 % pure.19.7 o-PhenanthrolineDissolve 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

47、 Calibration SolutionsTransfer 0.0, mL 1.0 mL,2.0 mL, 3.0 mL, 4.0 mL, 5.0 mL, and 6.0 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

48、 the precipitate just dissolves. Bring the pH of thesolution to 3.0 by adding 2 additional 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

49、to the mark with water.20.3 PhotometryTransfer a suitable portion of the reagentblank solution to a 1 cm absorption cell, and adjust theC560 1513spectrophotometer 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 solution against micrograms of iron per 100 mL ofsolution.21. Procedure21.1 Sample SolutionProceed in accordance