1、Designation: D 3682 01 (Reapproved 2006)Standard Test Method forMajor and Minor Elements in Combustion Residues fromCoal Utilization Processes1This standard is issued under the fixed designation D 3682; the number immediately following the designation indicates the year oforiginal adoption or, in th
2、e 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 covers the analysis of the commonlydetermined major and minor elemen
3、ts in combustion residuesfrom coal utilization processes.NOTE 1Test Methods D 1757 or D 5016 shall be used for determina-tion of sulfur.1.2 The values stated in SI units (IEEE/ASTM SI 10 ) shallto be regarded as the standard.1.3 This standard does not purport to address all of thesafety concerns, if
4、 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 regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 1757 Te
5、st Method for Sulfate Sulfur in Ash from Coaland CokeD 2013 Practice of Preparing Coal Samples for AnalysisD 3173 Test Method for Moisture in theAnalysis Sample ofCoal and CokeD 3174 Test Method forAsh in theAnalysis Sample of Coaland Coke from CoalD 3180 Practice for Calculating Coal and Coke Analy
6、sesfrom As-Determined to Different BasesD 5016 Test Method for Sulfur inAsh from Coal, Coke, andResidues from Coal Combustion Using High-TemperatureTube Furnace Combustion Method with Infrared Absorp-tionD 5142 Test Methods for Proximate Analysis of the Analy-sis Sample of Coal and Coke by Instrumen
7、tal ProceduresE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodIEEE/ASTM SI 10 Standard for Use of the InternationalSystem of Units (SI): The Modern Metric System3. Summary of Test Method3.1 The combustion residue to be analyzed is ignited in airat 750
8、C to a constant weight. The ash is fused within lithiumtetraborate (Li2B4O7) followed by a final dissolution of themelt in either dilute hydrochloric acid (HCl) or dilute nitricacid (HNO3). The solution is analyzed by atomic absorption/emission for applicable elements.4. Significance and Use4.1 A co
9、mpositional analysis of the ash in coal is oftenuseful in the total description of the quality of the coal.Knowledge of ash composition is also useful in predicting thebehavior of ashes and slags in combustion chambers. Utiliza-tion of the ash by-products of coal combustion sometimesdepends on the c
10、hemical composition of the ash.4.2 Note that the chemical composition of laboratory-prepared coal ash may not exactly represent the composition ofmineral matter in the coal or the composition of fly ash and slagresulting from commercial-scale burning of the coal.5. Apparatus5.1 Ashing Furnace, with
11、an adequate air circulation andcapable of having its temperature regulated between 700 and750C.5.2 Fusion Furnace, with an operating temperature of1000C.5.3 Platinum Dish, 35- to 85-mL capacity.5.4 Stirring Hotplate and Bars, operating temperature of200C.5.5 Atomic Absorption SpectrometerAny dual-ch
12、annel in-strument using a deuterium (D2) arc background corrector orother comparable simultaneous background correction system.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. It is intended that all reagents shall conform tothe specifications of the Committee on A
13、nalytical Reagents of1This test method is under the jurisdiction of ASTM Committee D05 on Coaland Coke and is the direct responsibility of Subcommittee D 05.29 on MajorElements in Ash and Trace Elements of Coal.Current edition approved April 1, 2006. Published April 2006. Originallyapproved in 1978.
14、 Last previous edition approved in 2001 as D 3682 01e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyr
15、ight ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the American Chemical Society, where such specifications areavailable.3Other grades may be used, provided it is firstascertained that the reagent is of sufficiently high purity topermit its u
16、se without lessening the accuracy of the determi-nation. The lithium tetraborate and lanthanum chloride re-agents in particular should be examined for alkali and alkalineearth contamination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean Type II reagent
17、water asdefined in Specification D 1193.6.3 Aluminum Stock Solution (1000-ppm aluminum).6.4 Calcium Stock Solution (1000-ppm calcium).6.5 Iron Stock Solution (1000-ppm iron).6.6 Lanthanum Chloride Solution (175-g/L lanthanumchloride (LaCl3) or equivalent 10 % lanthanum).6.7 Lithium Tetraborate (Li2B
18、4O7), powder.6.8 Magnesium Stock Solution (1000-ppm magnesium).6.9 Potassium Stock Solution (1000-ppm potassium).6.10 Silicon Stock Solution (200-ppm silicon) (Note 2).6.11 Sodium Stock Solution (1000-ppm sodium).6.12 Solvent AcidDilute 50 mL of concentrated hydro-chloric acid (sp gr 1.19) or 50 mL
19、of concentrated nitric acid(sp gr 1.42) to 1000 mL. Either acid solution may be used, butwhichever is chosen should be used throughout the subsequentsolution preparations.6.13 Titanium Stock Solution (1000-ppm titanium).NOTE 2Commercial silicon standards prepared from sodium silicatehave not proved
20、satisfactory. A standard stock solution can be prepared byfusing 0.1070 g of reignited spectrographic grade silica (SiO2)with1goflithium tetraborate, dissolving in solvent acid, and diluting to 250 mL asdescribed for sample preparation in 8.3.1 and 8.3.2. This solution is200-ppm silicon. Preferable
21、standard preparations for silica are made byfusion and dilution of ash sample(s) of known composition in accordancewith 8.3.1 and 8.3.2. The standard sample(s) should have a composition(s)similar to the unknown.7. Sample Preparation7.1 The combustion residue to be analyzed must first beignited in ai
22、r at 750C to a constant weight before analysis.Allow the ash to cool, transfer to an agate mortar, and grind topass a 74-m (No. 200) sieve. Reignite the ash at 750C for 1h, cool rapidly, and immediately weigh portions for analysis. Ifsamples are stored, reignite the ash before weighing or deter-mine
23、 the loss on ignition at 750C on a separate sampleweighted out at the same time as the analysis sample and makethe necessary corrections. Thoroughly mix each sample beforeweighing.7.2 If the ash is to be prepared from a coal, prepare the coalanalysis sample in accordance with Practice D 2013 by pul-
24、verizing the materials to pass a 250-m (No. 60) sieve.7.2.1 Analyze separate test portions of the coal for moistureand ash contents in accordance with Test Methods D 3173,D 3174,orD 5142 so that calculations to other bases can bemade.7.2.2 Prepare the ash from a thoroughly mixed analysissample of co
25、al. Spread the coal in a layer not over 6 mm (14in.) in depth in a fireclay or porcelain roasting dish. Place thedish in a cold muffle furnace and heat gradually so that thetemperature reaches 500C in 1 h and 750C in 2 h. Ignite at750C until all carbonaceous matter is removed. Proceed withthe prepar
26、ation of the ash in accordance with 7.1. If samplesare stored and the absorption of moisture or CO2, or both, is inquestion, reignite the ash using the 500-750C staged combus-tion before use. Alternatively, determine loss on ignition usingthe 500-750C staged combustion on a separate sampleweighed ou
27、t at the same time as the test portion and make thenecessary corrections. Thoroughly mix each sample beforeweighing.8. Procedure8.1 The solutions and proportions described below are fortypical ash samples as represented by American coals ofbituminous rank. Therefore, stronger or weaker dilutions may
28、be required to establish suitable concentrations for thoseelements of varying percents outside the range of the typicalsample. Each analyst must determine the sensitivity and linearrange of calibration of their equipment and choose concentra-tion ranges for standards compatible with the samples andi
29、nstrument specific to their own work.8.1.1 Calculations used in subsequent sections are devel-oped from the following general formula for percent concen-tration of element oxide, E, in moisture-free coal ash:E 5 C 2 B!/A 2 B!# 3 N/M! 3 F 3 100 (1)where:A = absorbance of standard;B = absorbance of bl
30、ank;C = absorbance of sample solution;N = element in standard, ppm;M = sample of solution, ppm; andF = conversion from element to oxide.NOTE 3Concentrations in the ash may be converted to the air-driedcoal basis using the following expression:C 5 AB/100!where:C = oxide in air-dried coal, %;A = oxide
31、 in ash, %; andB = ash as determined in Test Method D 3174 or Test MethodD 5142,%.See Practice D 3180 for procedures to convert values to other bases.8.2 To minimize the potential of contamination, the plati-numware must be prepared by boiling in solvent acid andrinsing thoroughly with reagent-grade
32、 water. After this initialcleaning, the platinumware must be handled with clean tongsand protected from further contamination from table tops, andso forth. All glassware used in analyses must be equally cleanand equally protected.3Reagent Chemicals, American Chemical Society Specifications, American
33、Chemical 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. Pharmacopeial Convention, Inc. (USPC),
34、Rockville,MD.D 3682 01 (2006)28.3 Sample Fusion and Solution:8.3.1 Weigh 0.1 6 0.0002 g of the sample as prepared in 7.3into a platinum dish (5.3)(Note 4) and add 0.5 g of Li2B4O7.Mix the ash and lithium tetraborate well, then add an additional0.5gofLi2B4O7to cover the mixture. Place the dish in a c
35、leansilica or refractory tray and place in a muffle furnace preheatedto 1000C; 15 min at 1000C is sufficient to fuse the mixturecompletely. Remove the tray and dish and cool to roomtemperature. Carefully rinse the bottom and outside of theplatinum dish to remove possible contamination, then place it
36、in a clean 250- or 400-mL beaker. Place a clean TFE-fluorocarbon-coated stirring magnet inside the dish, add 150mL of solvent acid to the beaker and dish, and place immedi-ately on the stirring hotplate. Heat the solution to just belowboiling temperature and maintain for not more than 30 minwith con
37、stant stirring. This time and temperature are sufficientto completely dissolve the melt. If stirring is not maintainedconstantly, some of the ash constituents are apt to precipitateand the analysis must be repeated.NOTE 4The use of graphite crucibles and subsequent dissolution offused beads from the
38、m was not investigated; however, their successful usein similar methods has been reported.48.3.2 Remove the beaker from the hotplate and permit tocool to room temperature. Quantitatively transfer the solutionto a 200-mL volumetric flask, wash the platinum dish andbeaker with small amounts of solvent
39、 acid and dilute to the200-mL mark with the solvent acid. This solution is 500 ppmwith respect to the total sample and contains 5 g/L of Li2B4O7solution.8.3.3 Solution 1Pipet 20 mL of the sample solutionprepared in 8.3.2 into a 50-mL volumetric flask and dilute tovolume with solvent acid. This solut
40、ion is 200 ppm withrespect to the total sample and contains 2 g/L of Li2B4O7solution.8.3.4 Solution 2Pipet 10 mL of the sample solutionprepared in 8.3.2 into a 100-mL volumetric flask, add 10 mL oflanthanum solution (see 6.7), and dilute to volume with solventacid. This solution is 50 ppm with respe
41、ct to the total sampleand contains 0.5 g/L of Li2B4O7solution.NOTE 5Lanthanum was included in the solution as a release agent inthose determinations that may require it (for example, calcium). Alterna-tive measures, such as the use of nitrous oxide flame, are permissible.9. Silicon Dioxide (SiO2)9.1
42、 Preparation of StandardsPrepare a series of standardsby combining the following volumes of the silicon stocksolution (see 6.10) with 1 mL of the aluminum stock solution(see 6.3) and diluting to 100 mL with the blank solution (see9.2). Only those standards need be prepared that bracket theexpected S
43、iO2concentrations in the samples.Silicon, StockSolution (6.12), mL Silicon, ppm Equivalent SiO2,%Silicon, StockSolution (6.12), mL Silicon, ppm Equivalent SiO2,%25 50 53.520 40 42.815 30 32.110 20 21.49.2 Blank SolutionPrepare a solution of 2 g/L of Li2B4O7solution in solvent acid.9.3 Sample Solutio
44、nUse the 200-ppm sample solution asprepared in 8.3.3.9.4 Atomic Absorption Operating ConditionsUse a sili-con hollow-cathode lamp and set the monochromator at 251.6nm. Use a nitrous oxide/acetylene flame. Adjust other instru-ment parameters to optimum for the particular equipment used.9.5 Determinat
45、ionRead out absorbance values for theblank solution, standard solutions, and sample solution. In thisand all subsequent determinations, those instruments soequipped may be calibrated to read out “percent concentration”directly. Determine percent SiO2as follows:SiO2,%5 C 2 B!/A 2 B!# 3 N 3 1.07 (2)wh
46、ere:A = absorbance of standard nearest C,B = absorbance of blank,C = absorbance of sample, andN = silicon in standard, ppm.10. Aluminum Oxide (Al2O3)10.1 Preparation of StandardsPrepare standard solutionscontaining from 10- to 30-ppm aluminum and dilute with blanksolution 9.2.10.2 Blank SolutionUse
47、the blank as prepared in 9.2.10.3 Sample SolutionUse Solution 1 as prepared in 8.3.3.10.4 Atomic Absorption Operating ConditionsUse an alu-minum hollow-cathode lamp and set the monochromator at309.2 nm. Use a nitrous oxide-acetylene flame. Adjust otherinstrument parameters to optimum for the particu
48、lar equipmentused.10.5 DeterminationRead out absorbance values for theblank solution, standard solutions, and sample solution. Deter-mine percent Al2O3as follows:Al2O3,%5 C 2 B!/A 2 B!# 3 N 3 0.94 (3)where:A = absorbance of standard nearest C,B = absorbance of blank,C = absorbance of sample, andN =
49、aluminum in standard, ppm.11. Iron Oxide (Fe2O3)11.1 Preparation of StandardsPrepare standard solutionscontaining from 2- to 10-ppm iron and 10 mL of lanthanumsolution per 100 mL. Dilute with blank solution (11.2).11.2 Blank SolutionPrepare a solution of solvent acidcontaining 0.5-g/L Li2B4O7.11.3 Sample SolutionUse Solution 2 as prepared in 8.3.4.11.4 Atomic Absorption Operating ConditionsUse an ironhollow-cathode lamp and set the monochromator at 248.3 nm.4Muter, R. B. and Nice, L. L., “Major and Minor Constituents in SiliceousM
