1、Designation: D 6349 07Standard 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 D 6349; the number immediately followi
2、ng 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method c
3、overs 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 state
4、d in SI units are to be regarded as thestandard.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 health practices and determine the applica-bility of reg
5、ulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD 1193 Specification for Reagent WaterD 2013 Practice for Preparing Coal Samples for AnalysisD 3173 Test Method for Moisture in theAnalysis
6、Sample ofCoal and CokeD 3180 Practice for Calculating Coal and Coke Analysesfrom As-Determined to Different BasesD 5142 Test Methods for Proximate Analysis of the Analy-sis Sample of Coal and Coke by Instrumental ProceduresE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precis
7、ion of a Test Method3. Summary of Test Method3.1 The sample to be analyzed is ashed under standardconditions and ignited to 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
8、, nitric, and hydrochloric acids. The solution isanalyzed by inductively coupled plasma-atomic emission spec-trometry (ICP) 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
9、transported to the plasma torch where excitationand emission occurs. Characteristic line emission spectra areproduced by a radio-frequency inductively coupled plasma. Agrating monochromator system is used to separate the emissionlines, and the intensities of the lines are monitored by photo-mutilpli
10、er tube or photodiode array detection. The photocur-rents from the detector are processed and controlled by acomputer system. A background correction technique is re-quired to compensate for variable background contribution tothe determination of elements. Background must be measuredadjacent to anal
11、yte lines of samples during analysis. Theposition selected for the background intensity measurement, oneither or both sides 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
12、same change in background intensity as occurs at theanalyte wavelength measured.4. Significance and Use4.1 A compositional analysis of coal and coke and theirassociated combustion residues are often useful in assessingtheir quality. Knowledge of the elemental composition of theassociated residues is
13、 also useful in predicting the elementalenrichment/depletion compositional behavior of ashes and1This 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
14、 approved June 1, 2007. Published July 2007. Originally approvedin 1998. Last previous edition approved in 2001 as D 6349 - 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information
15、, 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.slags in comparison to the concentration levels in the parentcoal. Utilization of the ash by-products and hazardous pot
16、entialmay 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 composition of fly ash and slag resulting fromcommerical-sc
17、ale 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 correction factors to compensate for theinterferences. The
18、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-tinuous or recombination phenomena, and background contr
19、i-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 theanalyte line. In addition, users of simultaneous multi
20、-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 determined by this methodand the recommended wavelengths using
21、 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 23lists some interference effects for the recom-mended wavelengths given in Table 1. The data in Table 2 areintended for use only as a rudimentary guide
22、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 develop and applycorrection factors to compensate for the in
23、terferences.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, especially insamples that may contain high dissolved solids or
24、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 techniques, or both.Another problem that can occur from high d
25、issolved 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, it has been reportedthat better control of the argon fl
26、ow 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-tion effects. Normally these effects are not pronounced
27、 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 standard addi-tion procedures. These types of interferences ca
28、n be highlydependent on matrix type and the specific analyte element.3Methods for Chemical Analysis of Water and Wastes , (EPA-600/4-79-020),Metals-4, Method 200.7 CLP-M.TABLE 2 Examples of Analyte Concentration Equivalents Arising from Interference at the 100-ppm (mg/L) Level3NOTE 1Dashes indicate
29、that no interference was observed even when interferents were introduced at the following levels:Al, Ca, and Fe = 1000 ppm,Mn = 200 ppm, and Mg = 100 ppm.InterferentsAnalyte Elements Wavelengths, nm Al Ca Fe Mg Mn TiAluminum 308.215 - - - - - - - - - - - - 0.21 - - -Barium 455.103 - - - - - - - - -
30、- - - - - - - - -Calcium 317.933 - - - - - - 0.01 0.01 0.04 0.03Iron 259.940 - - - - - - - - - - - - 0.12 - - -Magnesium 279.079 - - - 0.02 0.13 - - - 0.25 0.07Manganese 257.610 0.005 - - - 0.002 0.002 - - - - - -Silicon 288.148 - - - - - - - - - - - - - - - - - -Sodium 588.995 - - - - - - - - - - -
31、 - - - - 0.08TABLE 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, 364.44, 422.67Iron 259.940, 271.44, 238.204Magnesium 279.553, 279.08, 285.21, 277.983Manganese 257.610, 29
32、4.92, 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, 334.941D63490726. Apparatus6.1 Ashing Furnace, with an adequate air circulation (two tofour volume changes per minu
33、te) and capable of having itstemperature regulated between 700 and 750C.6.2 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
34、Crucibles, 35- to 85-mL capacity.Graphite crucibles with 10- to 15-mL capacity 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 pre
35、ssure that is developed during thedigestion, and resistant to oxidation. Other 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 seque
36、ntial or simultaneous spectrom-eter is suitable. Because of the differences 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. Sen
37、sitivity, instrumental detectionlimit, precision, linear dynamic range, and interference effectsmust 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 i
38、s the responsibility of the analyst toverify that the instrument configuration and operating 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
39、 chemicals shall beused in all tests. It is intended that all reagents shall conform tothe specifications of the Committee on Analytical Reagents ofthe American Chemical Society in which such specificationsare available.4Other grades may be used provided it is firstascertained that the reagent is of
40、 sufficiently high purity topermit its use without lessening the accuracy of the determi-nation.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean Type II reagent water asdefined by Specification D 1193.7.3 Standard Stock SolutionsStock solutions of 1000 pp
41、m(mg/L) for each element are needed for preparation of dilutestandards in the range from 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
42、 Standard SolutionStock solution of 1000ppm (mg/L) of yttrium (Y), scandium (Sc), indium (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 Ni
43、tric Acid Concentrated HNO3, sp gr 1.42.7.5.4 Nitric Acid (5 + 95)Dilute 50 mL of concentratednitric 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
44、mix-tures of lithium tetraborate (Li2B4O7) and anhydrous lithiummetaborate (LiBO3).7.7 Boric 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 mel
45、t and removalof the melt of cooled pellet.7.10 Standard Solution DiluentUse either 7.10.1 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 st
46、irring hot plate. Heat the mixture to justbelow boiling and maintain this temperature with 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 sol
47、ution cools to room temperature,dilute to 1000 mL with reagent grade water.7.10.2 Weigh 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 co
48、ntamination. Placethe cooled platinum dish containing the flux and a magneticstirring bar 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 temp
49、erature with con-stant stirring until the melt dissolves. This dissolution processshould 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 withreagent 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 th
