1、Designation: D 3683 04Standard Test Method forTrace Elements in Coal and Coke Ash by AtomicAbsorption1This standard is issued under the fixed designation D 3683; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. 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 method2describes a procedure for the deter-mination of beryllium, chromium, copper, manganese, nickel,lead, vanadium
3、, and zinc in coal ash or coke ash.NOTE 1Although not included, this test method can be applicable tothe determination of other trace elements, for example, cadmium.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of th
4、e user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.3 The values stated in SI units (IEEE/ASTM SI 10) shouldbe regarded as the standard.2. Referenced Documents2.1 ASTM Standards:3D 346 Practice for Co
5、llection and Preparation of CokeSamples For Laboratory AnalysisD 1193 Specification for Reagent WaterD 2013 Practice of Preparing Coal Samples for AnalysisD 3173 Test Method for Moisture in the Analysis Sample ofCoal and CokeD 3180 Practice for Calculating Coal and Coke Analysesfrom As-Determined to
6、 Different BasesD 5142 Test Methods for Proximate Analysis of the Analy-sis Sample of Coal and Coke by Instrumental Procedures4IEEE/ASTM SI 10 Standard for Use of the InternationalSystem of Units (SI): The Modern Metric SystemNOTE 2Practice D 2013 specifies coal ground to pass through a60-mesh (250-
7、m) screen. For the trace element determinations in this testmethod 100-mesh (150-m) coal is recommended.3. Summary of Test Method3.1 Coal or coke is ashed, the ash is dissolved by mineralacids, and the individual elements determined by atomicabsorption spectrometry.4. Significance and Use4.1 Many tr
8、ace elements occur in coal, primarily as a part ofthe mineral matter but may also be associated with the organicmatrix. Concern over release of certain trace elements to theenvironment as a result of coal utilization has made thedetermination of these elements an increasingly importantaspect of coal
9、 analysis.4.2 When coal ash is prepared in accordance with this testmethod, the eight elements listed in 1.1 are quantitativelyretained in the ash and are representative of concentrations inthe coal. Concentrations of these and other elements in powerplant ash, industrial process ash, fly ash, and s
10、o forth, may ormay not be representative of total quantities in the coal.5. Apparatus5.1 Atomic Absorption SpectrometerAny dual-channel in-strument using a deuterium (D2) arc background corrector orother comparable simultaneous background correction system.5.2 Muffle Furnace, with temperature contro
11、l.5.3 Bottles, polyethylene or polytetrafluoroethylene,125-mL capacity, with screw-cap lids, capable of withstandingtemperatures up to 130C.5.4 Volumetric Flasks, 100-mL capacity.5.5 Steam Bath.5.6 Analytical Balance, capable of weighing to 0.1 mg.5.7 Crucibles, 50-mL quartz or high silica.1This tes
12、t 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 in Coal.Current edition approved Oct. 1, 2004. Published November 2004. Originallyapproved in 1978. Last previous edition appro
13、ved in 2000 as D 3683 94 (2000).2For information concerning experimental work on which this test method isbased, see Bernas, B., “A New Method for the Decomposition and ComprehensiveAnalysis of Silicates by Atomic Absorption Spectrometry,” Analytical Chemistry,ANCHA, Vol 40, 1968, pp 168286.3For ref
14、erenced 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.4Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO B
15、ox C700, West Conshohocken, PA 19428-2959, United States.6. Reagents6.1 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 Chemic
16、al Society,where such specifications are available.5Other 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.6.2 Reagent WaterReagent water, conforming to Type IIof Specification D 11
17、93, shall be used for preparation ofreagents.6.3 Aqua Regia SolutionMix one part concentrated nitricacid (HNO3, sp gr 1.42), three parts concentrated hydrochloricacid (HCl, sp gr 1.19), and one part water.6.4 Boric Acid Solution, SaturatedDissolve 60 g of boricacid (H3BO3) in 1 L of deionized water.
18、6.5 Stock Solutions, StandardPrepare standard stock so-lutions from high-purity (99.9 % or better) metals, oxides, orsalts. Stock solutions of at least 100 ppm (g/ml) for eachmetal are convenient for preparation of dilute standards in therange from 10 to 0.01 ppm (g/mL) depending upon thesensitivity
19、 of the element and the instrumentation used.6.6 Hydrofluoric Acid (sp gr 1.15)Concentrated hydrof-luoric acid (HF).7. Sample7.1 Prepare the analysis sample in accordance with PracticeD 2013 or Practice D 346 by pulverizing the material to pass250-m (No. 60) sieve (Note 3).NOTE 3Analysis samples gro
20、und to pass a 150-m (No. 100) sieveare recommended for this test method.7.2 Analyze separate test portions for moisture content inaccordance with Test Methods D 3173 or D 5142 so thatcalculation to other bases can be made.8. Calibration and Standardization8.1 Calibration standards are prepared from
21、stock solutions(see 6.5) appropriately diluted so as to finally contain 1.5 % v/vaqua regia solution, 3 % v/v hydrofluoric acid (HF), and 3 %v/v H3BO3(Note 4). The corresponding absorbance responsefor each standard is plotted versus concentration for calibra-tion. Sample responses are compared direc
22、tly with the calibra-tion curve.NOTE 4It is important that the standards closely approximate thesample solution so that errors as a result of matrix differences are minimal.9. Procedure9.1 AshingAsh approximately 6 g (weighed to the nearest0.1 mg) of the analysis sample in an open 50-mL quartz orhig
23、h-silica crucible. Place the crucible in a cold muffle furnaceand heat gradually at such a rate that the temperature reaches300C in about 1 h. Continue heating so that a temperature of500C is reached at the end of the second hour. Continue theashing at 500C for an additional 2 h. Stir the sample onc
24、e eachhour until no carbonaceous materials remain. After cooling andweighing, finely grind the ash in a clean agate or mullite mortarand then reignite at 500C for 1 h. Cool and reweigh tocalculate the percent ash.NOTE 5Coke can be ignited to a constant weight at a temperature notexceeding 950C if di
25、fficulty in ashing is encountered. If a higher ashingtemperature is used, it should be recorded with results.9.2 DissolutionPlace ash samples (approximately 0.2 g)in 125-mL plastic bottles with screw caps (Note 7). Bottlesshould be capable of withstanding temperatures up to 130C.Add 3 mL of aqua reg
26、ia solution and 5 mL of HF to thesamples, tighten screw caps, and place the bottles on a steambath for at least 2 h. Add 50 mL of saturated H3BO3solutionto the resultant solution (Note 8). If a residue remains, themixture may be reheated for about1htohelp dissolve it (Note9). Cool the solutions to r
27、oom temperature and adjust theirvolume to 100 mL by the addition of deionized water. Prepareblanks by using the above procedure. Store samples in poly-ethylene bottles.NOTE 6Avoid the use of sulfates and sulfuric acid (H2SO4). Theyhave adverse effects on the flame, and some sulfates have low solubil
28、ity.NOTE 7To minimize contamination, clean laboratory ware in a 10 %solution of hot HCl and rinse thoroughly with deionized water (6.2).NOTE 8Boric acid (H3BO3) not only complexes F, but it also has beenshown to have good flame properties and acts as a flame buffer.NOTE 9If a residue persists it can
29、 be ignored. The trace elements areconsidered to be quantitatively extracted at this point.9.3 AnalysisUse conventional atomic absorption proce-dures and make background corrections for each element. Anitrous oxide/acetylene (N2O/C2H2) flame can be used forberyllium, chromium, and vanadium, while an
30、 air/acetyleneflame is used for cadmium, copper, manganese, nickel, lead,and zinc. Table 1 summarizes the instrumental parameters to beused.10. Calculation10.1 Convert concentrations in the ash to the air-dried coalbasis for reporting as follows:C 5 AB/100!5Reagent Chemicals, American Chemical Socie
31、ty 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. Pharmacopeia
32、l Convention, Inc. (USPC), Rockville,MD.TABLE 1 Instrument ParametersElement Wavelength, nm Oxidant-FuelBe 234.9 N2O-C2H2Cd 228.8 air-C2H2Cr 357.9 N2O-C2H2Cu 324.8 air-C2H2Mn 279.5 air-C2H2Ni 232.0 air-C2H2Pb 283.3 air-C2H2V 318.0 N2O-C2H2Zn 213.9 air-C2H2D3683042where:C = ppm (g/g) in air-dried coa
33、l,A = ppm (g/g) in ash, andB = % ash in air-dried coal.NOTE 10See Practice D 3180 for procedures to convert values toother bases.11. Precision and Bias611.1 Precision:11.1.1 Repeatability Limit (r)the value below which theabsolute difference between two test results calculated to a drybasis (Practic
34、e D 3180) of separate and consecutive testdeterminations, carried out on the same sample, in the samelaboratory, by the same operator, using the same apparatus onsamples taken at random from a single quantity of homogenousmaterial, may be expected to occur with a probability ofapproximately 95%. The
35、 repeatability limits determined by thistest method are listed in Table 2.11.1.2 Reproducibility (R)the value below which theabsolute difference between two test results calculated to a drybasis (Practice D 3180) carried out in different laboratoriesusing samples taken at random from a single quanti
36、ty ofmaterial that is as homogenous as possible, may be expected tooccur with a probability of approximately 95%. The reproduc-ibility limits determined by this test method are listed in Table3.11.2 BiasStandard Reference Material 1632, a NationalInstitute of Standards and Technology (NIST) certifie
37、d coalsample, was analyzed with the results which are tabulated inTable 4.NOTE 11The NIST value for beryllium is not certified and is given forinformational purposes only. Values for Test Method D 3683 represent themean of the means from four separate laboratories, each of which madefour replicate a
38、nalyses on four separate samples of the coal standard.12. Keywords12.1 coal; coal ash; coke ash; trace elements; atomic ab-sorption spectroscopy6Supporting data are available from ASTM Headquarters. Request RR:D05-1001.TABLE 2 RepeatabilityElementAir-Dried Coal, ppm (g/g)RepeatabilityARangeBBe 0.2 0
39、.5 to 5Cr 3 5 to 50Cu 2 5 to 50Mn 3 10 to 300Ni 1 5Ni 3 5 to 30Pb 2 10 to 100V 5 10 to 100Zn 3 50Zn 8 50 to 100AValues should be considered as a general guide for the kinds of repeatabilityand reproducibility obtainable and not necessarily as values from which nodeviation is permissible.BApproximate
40、 range of concentrations within which sample results used forstatistical evaluation fall.TABLE 3 ReproducibilityElementAir-Dried Coal, ppm (g/g)ReproducibilityARangeBBe 0.5 0.5 to 5Cr 5 5 to 50Cu 3 5 to 50Mn 6 50Mn 20 50 to 500Ni 3 5Ni 9 9 to 30Pb 9 10 to 100V 9 10 to 50V 20 50to100Zn 4 50Zn 17 50 t
41、o 100AValues should be considered as a general guide for the kinds of repeatabilityand reproducibility obtainable and not necessarily as values from which nodeviation is permissible.BApproximate range of concentrations within which sample results used forstatistical evaluation fall.D3683043ASTM Inte
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45、ndards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610
46、-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 4 BiasSRM 1632Air-Dried Coal, ppm (g/g)Be Cr Cu Mn Ni Pb V ZnNIST 1.5A20.2 6 0.5 18.2 6 2406 3156 1306 9356 3376 4D 3683 1.5 6 0.1 20.0 6 1 17.4 6 0.6 43.8 6 3 14.6 6 3 27.8 6 4 45.7 6 436 4ANot certified; for information purposes only.D3683044
