1、Designation:D635704 Designation: D6357 11Standard Test Methods forDetermination of Trace Elements in Coal, Coke, andCombustion Residues from Coal Utilization Processes byInductively Coupled Plasma Atomic Emission Spectrometry,Inductively Coupled Plasma Mass Spectrometry, andGraphite Furnace Atomic A
2、bsorption Spectrometry1This standard is issued under the fixed designation D6357; the number immediately following 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. Asuperscrip
3、t epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods pertain to the determination of antimony, arsenic, beryllium, cadmium, chromium, cobalt, copper, lead,manganese, molybdenum, nickel, vanadium, and zinc in coal and coke. These test methods
4、 can also be used for the analysis ofresidues from coal combustion processes.NOTE 1These test methods may be applicable to the determination of other trace elements.1.2 The values stated in SI units shall be regarded as the standard.1.3 This standard does not purport to address all of the safety con
5、cerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D121 Terminology of Coal and CokeD346 Pra
6、ctice for Collection and Preparation of Coke Samples for Laboratory AnalysisD1193 Specification for Reagent WaterD2013 Practice for Preparing Coal Samples for AnalysisD3173 Test Method for Moisture in the Analysis Sample of Coal and CokeD3180 Practice for Calculating Coal and Coke Analyses from As-D
7、etermined to Different BasesD4621Guide for Quality Management in an Organization That Samples or Tests Coal and Coke 7448 Practice for Establishingthe Competence of Laboratories Using ASTM Procedures in the Sampling and Analysis of Coal and CokeD5142Test Methods for Proximate Analysis of the Analysi
8、s Sample of Coal and Coke by Instrumental Procedures 7582 TestMethods for Proximate Analysis of Coal and Coke by Macro Thermogravimetric AnalysisE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 Other Documents:EPA/600/4-91/010 Methods for the Deter
9、mination of Metals in Environmental Samples33. Terminology3.1 DefinitionsDefinitions applicable to these test methods are listed in Terminology D121.4. Summary of Test Method4.1 The coal or coke to be analyzed is ashed under controlled conditions, digested by a mixture of aqua-regia and hydrofluoric
10、acid, and finally dissolved in 1 % nitric acid. Combustion residues are digested on an as-received basis. The concentration ofindividual trace elements is determined by either inductively coupled atomic emission spectrometry (ICPAES) or inductively1These test methods are under the jurisdiction of AS
11、TM Committee D05 on Coal and Coke and are the direct responsibility of Subcommittee D05.29 on Major Elementsin Ash and Trace Elements of Coal.Current edition approved Oct.April 1, 2004.2011. Published November 2004.April 2011. Originally published in 1996. Last previous edition approved in 20002004
12、asD6357-00a.D6357 - 04. DOI: 10.1520/D6357-04.10.1520/D6357-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM webs
13、ite.3Available from Superintendent of Documents, U.S. Printing Office, Washington, DC 20402.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possi
14、ble to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, Wes
15、t Conshohocken, PA 19428-2959, United States.coupled plasma mass spectrometry (ICPMS). Selected elements that occur at concentrations below the detection limits of ICPAEScan be quantitatively analyzed by graphite furnace atomic absorption spectrometry (GFAA).5. Significance and Use5.1 Coal contains
16、several elements whose individual concentrations are generally less than 0.01 %. These elements arecommonly and collectively referred to as trace elements. These elements primarily occur as part of the mineral matter in coal. Thepotential release of certain trace elements from coal combustion source
17、s has become an environmental concern.5.2 The ash prepared in accordance with these provisional test methods quantitatively retains the elements listed in 1.1 and isrepresentative of their concentrations in the coal or coke.6. Apparatus6.1 Inductively Coupled Plasma Atomic Emission Spectrometer (ICP
18、AES)The spectrometer system may be either simulta-neous or sequential, vacuum or purged, but must include computer-controlled background correction.6.1.1 Argon Gas SupplyHigh purity (99.99 %).6.1.2 Mass Flow ControllersA mass-flow controller to regulate the nebulizer gas is required. Mass flow contr
19、ollers on theintermediate and outer torch gas flows are recommended.6.2 Inductively Coupled Plasma Mass Spectrometer (ICPMS)The spectrometer system must be capable of scanning the massrange of the elements to be analyzed.6.2.1 Argon Gas Supply, high purity (99.99 %).6.2.2 The use of a variable speed
20、 peristaltic pump for delivering sample solution to the nebulizer, a mass-flow controller on thegas supply to the nebulizer, and a water-cooled spray chamber are highly recommended.6.3 Atomic Absorption Spectrometer with Graphite Furnace (GFAA), having background correction capable of removingnonspe
21、cific absorbance.6.3.1 Single-Element Hollow Cathode or Single-Element Electrodeless Discharge Lamps.6.3.2 Single-Output Device, capable of recording and evaluating peak area and peak shape.6.3.3 Pyrolytic Coated Graphite Tubes and Platforms.6.3.4 Argon Gas Supply, high purity (99.99 %).6.3.5 Autosa
22、mplerAlthough not specifically required, the use of an autosampler is highly recommended.6.4 Muffle Furnace, with temperature control and with air circulation as specified in 9.1.6.5 Analytical Balance, capable of weighing to 0.1 mg.6.6 Teflon Beakers, 100- or 200-mL capacity.6.7 Hot Plate, capable
23、of regulating temperature between 90 to 150C.6.8 Volumetric Flasks, 100- and 10-mL capacity.6.9 HDPE Bottles, 100-mL capacity.6.10 Crucibles, 50-mL quartz or high silica.7. Reagents7.1 Purity of ReagentsAll acids used in these test methods must be trace metal purity grade or equivalent. Redistilled
24、acidsare acceptable.7.2 Purity of WaterThe purity of the water used in these test methods shall be equivalent to ASTM Type II reagent water ofSpecification D1193.7.3 Aqua Regia SolutionMix one part concentrated nitric acid (HNO3, sp. gr. 1.42) and three parts concentrated hydrochloricacid (HCl, sp.
25、gr. 1.9).7.4 Hydrofluoric AcidConcentrated (HF, sp. gr. 1.15).7.5 ICP Calibration StandardsAqueous multielement solutions made up in 1 % HNO3are used for calibration of ICPAES andICPMS systems. The standards may be purchased or prepared from high-purity grade chemicals or metals.7.5.1 GFAA Stock Sta
26、ndard Solution (1000 ppm)Single-element standards either purchased or prepared from high-puritygrade chemicals or metals.7.5.2 GFAA Intermediate Stock Standard Solution (1 ppm)Add 0.1 mL of stock standard solution (7.5.1) and 1 mL ofconcentrated nitric acid to a 100-mL volumetric flask. Dilute to vo
27、lume with water.7.6 Magnesium Nitrate Solution Matrix modifier (see Note 2), (106g/LMg(NOMatrix modifier (106g/L Mg(NO3)26H2O) for thedetermination of arsenic and antimony, equivalent to 10 000-ppm magnesium.NOTE2A7.6.1 A matrix modifier is used to minimize GFAA interference effects by selective vol
28、atilization of either the analyte or thematrix components. Other matrix modifiers such as nickel nitrate or palladium nitrate can be used. The analyst should comparemodifiers to establish optimum performance as outlined in 10.1.7.7 Blank SolutionsAll of the test methods in this standard require two
29、types of blank solutions. A calibration blank that isused to establish the analytical calibration curve and a method blank which is used to evaluate possible contamination and assessspectral background.D6357 1127.7.1 Calibration BlankA 1 % nitric acid solution. When using matrix modifiers of GFAA, t
30、he calibration blank shall alsocontain the same equivalent concentration.7.7.2 Method BlankConsists of all the reagents in the same volumes as used in preparing the samples. The method blank shallbe processed through the entire sample digestion scheme.8. Analysis Sample8.1 Samples of coal and coke s
31、hall be prepared in accordance with Practice D2013 or Practice D346.8.2 Standard practices for the sampling and preparation of residues from coal utilization processes have not been established.Some of these materials are highly abrasive. The use of high speed pulverizers for size reduction shall be
32、 avoided. The use of jawcrushers followed by final preparation in an agate mortar and pestle is recommended to prevent contamination of the sample.8.3 Analyze separate test portions for moisture content in accordance with Test Methods D3173 and D5142 D7582 so thatcalculations to other bases can be m
33、ade.9. Procedure9.1 AshingWeigh to the nearest 0.1 mg enough of the coal or coke sample that will yield approximately 0.5 g of ash into anopen 50-mL quartz or high-silica crucible. Place the crucible in a cold muffle furnace. Adjust the temperature control so that thefurnace reaches a temperature of
34、 300C in 1 h and then 500C in the second hour. Maintain the furnace temperature at 500C fora minimum of 2 h, stirring the sample occasionally. Ashing is complete when no visible evidence of carbonaceous materialremains. Cool the samples to room temperature under conditions that minimize the absorpti
35、on of water. Grind the ash to pass a150-m (No. 100) U.S.A. standard sieve in an agate mortar then reignite at 500C for 1 h. Cool the ash and store in a desiccator.Determine the percentage of ash by analyzing under the same conditions a separate portion of the analysis sample.NOTE3If 2If all the ash
36、from 9.1 is quantitatively transferred for digestion in 9.2, it is not necessary to sieve and grind the ash. Results from 11.2.3,12.3, or 13.1.3.8 13.1.4.8 are then ppm of the element in the as-determined sample.9.2 DissolutionWeigh 0.2000 to 0.5000 g of the thoroughly blended ash prepared according
37、 to 9.1 into a 100- or 200-mLTeflon beaker. Add 20 mL of aqua regia and 20 mL of concentrated hydrofluoric acid to the beaker. Place the beaker on a hot platethat has been adjusted to 130 to 150C. Heat the mixture to dryness, but do not bake. After the solution has evaporated, rinse thebeaker walls
38、with deionized water and heat this solution to dryness, again being careful not to bake the sample. Remove the beakerfrom the hot plate and cool to room temperature. Add 1 mL of concentrated nitric acid and 20 mL of deionized water to the beaker.Heat the contents on a hot plate at 90 to 100C until t
39、he sample is in solution. If a residue remains after1hofheating, it maybe ignored. The trace elements are considered to be quantitatively extracted at this point. Remove the beaker from the hot plateand allow the solution to cool to room temperature. Transfer the cool solution to a 100-mL volumetric
40、 flask and dilute to volumewith deionized water. If the solution is not to be analyzed immediately, transfer to a HDPE bottle to avoid adsorption of lead duringstorage. Prepare a method blank (7.7.2) with each batch of samples to be analyzed.NOTE4To 3To minimize contamination, clean laboratory ware
41、in a 1:1 solution of HNO3followed by a 1:1 solution of HCl then rinse thoroughlywith deionized water.10. Analysis10.1 Because of the differences between various makes and models of instruments, all instrumental operating instructionscannot be provided. Instead, the analyst shall refer to the instruc
42、tions provided by the manufacturer of the particular instrument.Sensitivity, instrumental detection limit, linear dynamic range, interference effects, and appropriate background correction shall beinvestigated and established for each individual analyte on that particular instrument.11. Test Method
43、AInductively Coupled Plasma Atomic Emission Spectroscopy11.1 Table 1 shows the elements listed in 1.1 along with some suggested wavelengths for inductively coupled plasma atomicemission spectrometry (ICPAES). Other wavelengths may be substituted if they can provide the needed sensitivity and are tre
44、atedaccording to the provisions of 10.1. Also shown are estimated detection limits.11.2 Calibration ProcedureCalibrate the instrument according to the procedure recommended by the manufacturer using acalibration blank and aqueous multielement standards made up in 1 % trace metal grade HNO3. All cali
45、bration solutions must alsocontain an internal standard (see Note 5Note 4). Records for all calibrations must be in accordance with Guide D4621D7448.NOTE5An 4An internal standard is needed to compensate for:1. Differences in physical properties (such as viscosity) between the calibration standard an
46、d the test samples and2. Drift caused by thermal changes in the laboratory which will affect the instrument optics.An appropriate internal standard element should:(i) not be naturally present in the test samples in appreciable concentrations,(ii) not present spectral interferences with any analyte,(
47、iii) be a strong emitter so that its relative concentration can be kept low, and(iv) be as chemically similar to the analyte as possible.11.2.1 Initial Calibration VerificationBefore analyzing test samples, analyze the method blank and verify the propercalibration of the instrument by analyzing a re
48、ference material that has traceability to an internationally recognized certifyingD6357 113agency such as NIST. Results for the reference material must be within the stated uncertainty limits or the calibration proceduremust be repeated.11.2.2 Periodic Calibration Verification and RecalibrationIn ac
49、cordance with Guide D4621D7448, analyze a control samplesuch as NIST on a periodic basis. Results obtained for the control sample must be within 10 % of the stated value or all resultsobtained since the last successful control check of that element must be rejected and the calibration procedure repeated.11.2.3 CalculationCalculate the concentration of the element in the ash as follows:C 5 A 3 df!/W 3 100! (1)where:C = weight percent of the element in the ash,df = dilution factor,A = ppm of the element in solution, andW = weight of the sa
