ASTM D6349-2009 7500 Standard Test Method for Determination of Major and Minor Elements in Coal Coke and Solid Residues from Combustion of Coal and Coke by Inductively Coupled Plas.pdf

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1、Designation: D6349 09Standard Test Method forDetermination of Major and Minor Elements in Coal, Coke,and Solid Residues from Combustion of Coal and Coke byInductively Coupled PlasmaAtomic EmissionSpectrometry1This standard is issued under the fixed designation D6349; the number immediately following

2、 the designation indicates the year oforiginal adoption 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.1. Scope1.1 This test method cove

3、rs a procedure for the analysis ofthe commonly determined major and minor elements in coal,coke, and solid residues from combustion of coal and coke.These residues may be laboratory ash, bottom ash, fly ash, fluegas desulfurization sludge, and other combustion processresidues.1.2 The values stated i

4、n SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 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 establish appro-priate safety and hea

5、lth practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD1193 Specification for Reagent WaterD2013 Practice for Preparing Coal Samples for Analy

6、sisD3173 Test Method for Moisture in the Analysis Sample ofCoal and CokeD3180 Practice for Calculating Coal and Coke Analysesfrom As-Determined to Different BasesD5142 Test Methods for ProximateAnalysis of theAnalysisSample of Coal and Coke by Instrumental ProceduresE691 Practice for Conducting an I

7、nterlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standard:3ISO/IEC Guide 99:2007 International vocabulary of metrol-ogy - Basic and general concepts and associated terms(VIM)3. Summary of Test Method3.1 The sample to be analyzed is ashed under standardconditions and ignited to

8、constant weight. The ash is fused witha fluxing agent followed by dissolution of the melt in diluteacid solution. Alternatively, the ash is digested in a mixture ofhydrofluoric, nitric, and hydrochloric acids. The solution isanalyzed by inductively coupled plasma-atomic emission spec-trometry (ICP)

9、for the elements. The basis of the method is themeasurement of atomic emissions. Aqueous solutions of thesamples are nebulized, and a portion of the aerosol that isproduced is transported to the plasma torch where excitationand emission occurs. Characteristic line emission spectra areproduced by a r

10、adio-frequency inductively coupled plasma. Agrating monochromator system is used to separate the emissionlines, and the intensities of the lines are monitored by photo-mutilplier tube or photodiode array detection. The photocur-rents from the detector are processed and controlled by acomputer system

11、. A background correction technique is re-quired to compensate for variable background contribution tothe determination of elements. Background must be measuredadjacent to analyte lines of samples during analysis. Theposition selected for the background intensity measurement, oneither or both sides

12、of the analytical line, will be determined bythe complexity of the spectrum adjacent to the analyte line. Theposition used must be free of spectral interference and reflectthe same change in background intensity as occurs at theanalyte wavelength measured.4. Significance and Use4.1 A compositional a

13、nalysis of coal and coke and theirassociated combustion residues are often useful in assessing1This test method is under the jurisdiction of ASTM Committee D05 on Coaland Coke and is the direct responsibility of Subcommittee D05.29 on MajorElements in Ash and Trace Elements of Coal.Current edition a

14、pproved Nov. 1, 2009. Published December 2009. Originallyapproved in 1998. Last previous edition approved in 2008 as D6349 - 081. DOI:10.1520/D6349-09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStan

15、dards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from International Organization for Standardization (ISO), 1 rue deVaremb, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.1Copyright ASTM International, 100 Barr Harbor Drive, PO

16、Box C700, West Conshohocken, PA 19428-2959, United States.their quality. Knowledge of the elemental composition of theassociated residues is also useful in predicting the elementalenrichment/depletion compositional behavior of ashes andslags in comparison to the concentration levels in the parentcoa

17、l. Utilization of the ash by-products and hazardous potentialmay also depend on the chemical composition and leachabilityof the inorganic constituents of the coal ash.4.2 The chemical composition of laboratory-prepared ashmay not exactly represent the composition of mineral matter incoal or the comp

18、osition of fly ash and slag resulting fromcommerical-scale burning of the coal.5. Interferences5.1 Several types of interference effects may contribute toinaccuracies in the determination of major and minor elements.The analyst should follow the manufacturers operating guideto develop and apply corr

19、ection factors to compensate for theinterferences. The interferences can be classified as spectral,physical, and chemical.5.1.1 Spectral interferences can be categorized as overlap ofa spectral line from another element, unresolved overlap ofmolecular band spectra, background contribution from con-t

20、inuous or recombination phenomena, and background contri-bution from stray light from the line emission of high concen-tration elements. The second effect may require selection of analternate wavelength. The third and fourth effects can usuallybe compensated by a background correction adjacent to th

21、eanalyte line. In addition, users of simultaneous multi-elementinstrumentation must assume the responsibility of verifying theabsence of spectral interference from an element that couldoccur in a sample but for which there is no channel in theinstrument array.5.1.2 Table 1 lists the elements determi

22、ned by this methodand the recommended wavelengths using conventional nebu-lization. Sulfur may only be determined if the sample isdissolved by the mixed acid dissolution described in 10.3.2.5.1.3 Table 24lists some interference effects for the recom-mended wavelengths given in Table 1. The data in T

23、able 2 areintended for use only as a rudimentary guide for the indicationof potential spectral interferences. For this purpose, linearrelations between concentration and intensity for the analytesand the interferents can be assumed. The analyst should followthe manufacturers operating guide to devel

24、op and applycorrection factors to compensate for the interferences.5.1.4 Physical interferences are generally considered to beeffects associated with the sample nebulization and transportprocesses. Such properties as change in viscosity and surfacetension can cause significant inaccuracies, especial

25、ly insamples that may contain high dissolved solids or acid con-centrations, or both. The use of a peristaltic pump is recom-mended to lessen these interferences. If these types of inter-ferences are operative, they must be reduced by dilution of thesample or utilization of standard addition techniq

26、ues, or both.Another problem that can occur from high dissolved solids issalt buildup at the tip of the nebulizer. This affects aerosol flowrate causing instrumental drift. Wetting the argon beforenebulization, the use of a tip washer, or sample dilution havebeen used to control this problem. Also,

27、it has been reportedthat better control of the argon flow rate, particularly nebulizerflow, improves instrument precision. This is accomplished withthe use of mass flow controllers.5.1.5 Chemical interferences are characterized by molecularcompound formation, ionization effects, and solute vaporiza-

28、tion effects. Normally these effects are not pronounced with theICP technique. However, if such effects are observed they canbe minimized by careful selection of operating conditions (thatis, incident power, observation position, and so forth), bybuffering of the sample, matrix matching, and standar

29、d addi-tion procedures. These types of interferences can be highlydependent on matrix type and the specific analyte element.6. Apparatus6.1 Ashing Furnace, with an adequate air circulation (two tofour volume changes per minute) and capable of having itstemperature regulated between 700 and 750C.6.2

30、Fusion Furnace, with an operating temperature of 1000to 1200C.6.3 Meeker-Type Burner, with inlets for fuel gas (propane ornatural gas) and compressed air, capable of flame temperaturesof 1000 to 1200C.6.4 Platinum Dishes or Crucibles, 35- to 85-mL capacity.Graphite crucibles with 10- to 15-mL capaci

31、ty may also beused.6.5 Stirring Hotplate and Bars, with operating temperatureup to 200C.6.6 Polycarbonate Bottles, 250-mL capacity with an O-ringseal and screw cap, capable of withstanding temperatures of100 to 130C, the pressure that is developed during thedigestion, and resistant to oxidation. Oth

32、er types of bottles orvials may be used provided they are capable of withstandingthe temperatures and pressures developed duing the digestion.6.7 Inductively Coupled Plasma-Atomic Emission Spec-trometer (ICP), either a sequential or simultaneous spectrom-eter is suitable. Because of the differences

33、between variousmakes and models of satisfactory instruments, no detailedoperating instructions can be provided. Instead, the analystshould follow the instructions provided by the manufacturer ofthe particular instrument. Sensitivity, instrumental detectionlimit, precision, linear dynamic range, and

34、interference effects4Methods for Chemical Analysis of Water and Wastes , (EPA-600/4-79-020),Metals-4, Method 200.7 CLP-M.TABLE 1 Recommended Wavelengths for Elements Determinedby ICPElement Wavelengths, nmAluminum 396.152, 256.80, 308.215, 309.271Barium 455.403, 493.41, 233.53Calcium 317.93, 315.887

35、, 364.44, 422.67Iron 259.940, 271.44, 238.204Magnesium 279.553, 279.08, 285.21, 277.983Manganese 257.610, 294.92, 293.31, 293.93Phosphorous 178.287, 214.900Potassium 766.491, 769.896Silicon 212.412, 288.16, 251. 611Sodium 588.995, 589.592Strontium 421.55Sulfur 182.04Titanium 337.280, 350.50, 334.941

36、D6349 092must be investigated and established for each individualanalyte line on that particular instrument. All measurementsmust be within the instruments linear range in which correc-tion factors are valid. It is the responsibility of the analyst toverify that the instrument configuration and oper

37、ating condi-tions used satisfy the analytical requirements of this methodand to maintain quality control data confirming instrumentperformance and analytical results.7. Reagents7.1 Purity of ReagentsReagents grade chemicals shall beused in all tests. It is intended that all reagents shall conform to

38、the specifications of the Committee on Analytical Reagents ofthe American Chemical Society in which such specificationsare available.5Other grades may be used provided it is firstascertained that the reagent is of sufficiently high purity topermit its use without lessening the accuracy of the determ

39、i-nation.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean Type II reagent water asdefined by Specification D1193.7.3 Standard Stock SolutionsStock solutions of 1000 ppm(mg/L) for each element are needed for preparation of dilutestandards in the range from

40、 0.1 to 100 ppm. Prepare standardstock solutions from 99.999 % purity metals or salts. Alterna-tively, one can use commercially available stock solutionsspecifically prepared for ICP-AES spectroscopy.7.4 Internal Standard SolutionStock solution of 1000ppm (mg/L) of yttrium (Y), scandium (Sc), indium

41、 (In), orother suitable element not found in significant concentrationsin the test samples.7.5 Acids:7.5.1 Hydrochloric AcidConcentrated HCl. sp gr 1.19.7.5.2 Hydrofluoric AcidConcentrated HF, sp gr 1.17.7.5.3 Nitric Acid Concentrated HNO3, sp gr 1.42.7.5.4 Nitric Acid (5 + 95)Dilute 50 mL of concen

42、tratednitric acid to 1000 mL.7.5.5 Mixed Acid Solution, 70/30 HCl/HFMix seven partsconcentrated hydrochloric acid and three parts concentratedhydrofluoric acid.7.6 Fluxing Agents Lithium tetraborate, Li2B4O7, or mix-tures of lithium tetraborate (Li2B4O7) and anhydrous lithiummetaborate (LiBO3).7.7 B

43、oric Acids Solution1.5 %.7.8 Hydrogen Peroxide30%7.9 Wetting AgentsApproximately 0.1 g of reagent gradelithium iodide (LiI) or other suitable wetting agent may beadded to the flux to facilitate pooling of the melt and removalof the melt of cooled pellet.7.10 Standard Solution DiluentUse either 7.10.

44、1 or7.10.2.7.10.1 Weigh 4 g, to the nearest 0.0001 g, of fluxing agent(see 7.6) into a clean 1000-mL beaker containing a magneticstirring bar. Add 500 mL of5+95nitric acid (see 7.5.4)tothebeaker and place on a stirring hot plate. Heat the mixture to justbelow boiling and maintain this temperature wi

45、th constantstirring until the fluxing agent dissolves. This dissolutionprocess should take about 30 min or less (see Note 1).Quantitatively transfer the warm solution to a 1000-mL volu-metric flask. After the solution cools to room temperature,dilute to 1000 mL with reagent grade water.7.10.2 Weigh

46、4 g, to the nearest 0.0001 g, of fluxing agent(see 7.6) into a platinum dish (or crucible). Heat to 1000C toform a liquid and cool. Carefully rinse the bottom and outsideof the platinum dish to remove possible contamination. Placethe cooled platinum dish containing the flux and a magneticstirring ba

47、r into a clean 1000-mL beaker. Add 500 mL of 5 +95 nitric acid (see 7.5.4) to the beaker and place immediatelyon the stirring hotplate. Heat the mixture to just below theboiling temperature and maintain this temperature with con-stant stirring until the melt dissolves. This dissolution processshould

48、 take about 30 min (see Note 1). After dissolutionremove the platinum dish after rinsing with reagent water andcollecting the washings in the acid solution. Quantitativelytransfer the warm solution to a 1000-mLvolumetric flask.Afterthe solution cools to room temperature, dilute to 1000 mL withreagen

49、t grade water.NOTE 1This time and temperature are sufficient to dissolve the meltcompletely. If stirring is not maintained constantly, some of the materialmay not dissolve, and the final solution must be filtered before use.5Reagent 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 National Formulary, U.S. Pharma