1、Designation: D4239 12D4239 13Standard Test Method forSulfur in the Analysis Sample of Coal and Coke Using High-Temperature Tube Furnace Combustion1This standard is issued under the fixed designation D4239; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 Th
3、is test method covers the determination of sulfur in samples of coal or coke by high-temperature tube furnace combustion.1.1.1 Two analysis methods are described.1.2 When automated equipment is used, either method can be classified as an instrumental method.1.3 The values stated in SI units are to b
4、e regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and
5、 determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D346 Practice for Collection and Preparation of Coke Samples for Laboratory AnalysisD2013 Practice for Preparing Coal Samples for AnalysisD3173 Test Method for Moisture in the Analysis Sampl
6、e of Coal and CokeD3176 Practice for Ultimate Analysis of Coal and CokeD3180 Practice for Calculating Coal and Coke Analyses from As-Determined to Different BasesD7448 Practice for Establishing the Competence of Laboratories UsingASTM Procedures in the Sampling andAnalysis of Coaland CokeD7582 Test
7、Methods 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 ISO Standard:3ISO 11722 Solid Mineral Fuels-Hard Coal Determination of Moisture in the general analysis test sample
8、by drying in nitrogen3. Summary of Test Method3.1 Combustion Method A (1350C)A weighed test portion of sample is burned in a tube furnace at a minimum combustiontube operating temperature of 1350C in a stream of oxygen. During combustion at temperatures above 1350 C, the sulfur andsulfur compounds c
9、ontained in the sample are decomposed and oxidized almost exclusively to gaseous sulfur dioxide, SO2.Moisture and particulates are removed from the gas by filters. The gas stream is passed through a cell in which sulfur dioxide ismeasured by an infrared (IR) absorption detector. Sulfur dioxide absor
10、bs IR energy at a precise wavelength within the IR spectrum.Energy is absorbed as the gas passes through the cell body in which the IR energy is being transmitted: thus, at the detector, lessenergy is received.All other IR energy is eliminated from reaching the detector by a precise wavelength filte
11、r. Thus, the absorptionof IR energy can be attributed only to sulfur dioxide whose concentration is proportional to the change in energy at the detector.One cell is used as both a reference and a measurement chamber. Total sulfur as sulfur dioxide is detected on a continuous basis.3.1.1 One procedur
12、e for Method A uses coal or coke reference materials to calibrate the sulfur analyzer. A second procedurefor Method A uses a pure substance, BBOT, to calibrate the sulfur analyzer.1 This test method is under the jurisdiction of ASTM Committee D05 on Coal and Coke and is the direct responsibility of
13、Subcommittee D05.21 on Methods of Analysis.Current edition approved Feb. 1, 2012Oct. 1, 2013. Published February 2012October 2013. Originally approved in 1983. Last previous edition approved in 20112012 asD4239 11.D4239 12. DOI: 10.1520/D4239-12.10.1520/D4239-13.2 For referencedASTM standards, visit
14、 theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, C
15、ase postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.This 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 possible to adequately depict al
16、l 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, West Conshohocken, PA 19428-29
17、59. United States13.2 Combustion Method B (1150C)A weighed test portion of sample is burned in a quartz combustion tube in a stream ofoxygen with an equal or excess weight of tungsten trioxide (WO3). Sulfur is oxidized during the reaction of the sample and WO3.The tube furnace is operated at a minim
18、um combustion tube operating temperature of 1150C and tin (Sn) sample boats areutilized. Moisture and particulates are removed from the combustion gas by filters. The gas stream is then passed through a cellin which sulfur dioxide is measured by an infrared (IR) absorption detector. Sulfur dioxide a
19、bsorbs IR energy at a precisewavelength within the IR spectrum. Energy is absorbed as the gas passes through the cell body in which the IR energy is beingtransmitted: thus, at the detector, less energy is received. All other IR energy is eliminated from reaching the detector by a precisewavelength f
20、ilter. Thus, the absorption of IR energy can be attributed only to sulfur dioxide whose concentration is proportionalto the change in energy at the detector. One cell is used as both a reference and a measurement chamber. Total sulfur as sulfurdioxide is detected on a continuous basis.4. Significanc
21、e and Use4.1 Sulfur is part of the ultimate analysis of coal and coke.4.2 Results of the sulfur analysis are used for evaluation of coal preparation and cleaning, evaluation of potential sulfuremissions from coal and coke combustion or conversion processes, and evaluation of coal and coke quality in
22、 relation to contractspecifications, as well as for scientific purposes.4.3 The competency of laboratories with respect to use of this standard can be established through reference to Practice D7448.5. Sample5.1 Pulverize the sample to pass No. 60 (250-m) sieve and mix thoroughly in accordance with
23、Practice D2013 or PracticeD346.5.2 Analyze a separate portion of the analysis sample for moisture content in accordance with Test Method D3173, or D7582or ISO 11722 for calculations to other than the as-determined basis.5.3 Procedures for calculating as-determined sulfur values obtained from the ana
24、lysis sample to other bases are described inPractices D3176 and D3180.6. ApparatusCombustion Method A (1350C)6.1 Measurement ApparatusEquipped to combust the sample as described in 3.1 (See Fig. 1).6.2 Tube FurnaceCapable of heating the hot zone or outer surface of the combustion tube, or both (6.3)
25、 to at least 1350C.It is normally heated electrically using resistance rods, a resistance wire, or molybdenum disilicide elements. Specific dimensionscan vary with manufacturers design.FIG. 1 Apparatus for the Determination of Sulfur by the Infrared Detection, Method AD4239 1326.3 Combustion TubeMad
26、e of mullite, porcelain, or zircon with provisions for routing the gases produced by combustionthrough the infrared cell. The tube may have a boat stop made of reticulated ceramics heated to 1350C that serves to completethe combustion of sulfur containing materials.6.4 Sample Combustion Boats, made
27、of iron-free material and of a convenient size suitable for the dimensions of the combustiontube.6.5 Boat PullerWhere required, a rod of a heat-resistant material with a bent or disk end to insert and remove boats from thecombustion tube.Combustion Method B (1150C)6.6 Measurement ApparatusEquipped t
28、o combust the sample as described in 3.2 (See Fig. 2)6.7 Tube FurnaceCapable of heating the hot zone or outer surface of the combustion tube, or both (6.8) to at least 1150C.It is normally heated electrically using resistance wire. Specific dimensions can vary with manufacturers design.6.8 Combustio
29、n TubeMade of quartz with provisions for routing the gases produced by combustion through the infrared cell.6.9 Sample Combustion BoatMade of an iron-free tin material and of a convenient size suitable for the dimensions of thecombustion tube.7. Reagents7.1 Purity of ReagentsUse reagent grade chemic
30、als in all tests. Unless otherwise indicated, it is intended that all reagentsconform to the specifications of the Committee onAvailable Reagents of theAmerican Chemical Society, where such specificationsare available.4 Other grades can be used, provided it is first ascertained the reagent is of suf
31、ficiently high purity to permit its usewithout lessening the accuracy of the determination.7.2 Magnesium Perchlorate(WarningMagnesium perchlorate is a strong oxidizing agent. Do not regenerate the absorbent.Do not allow contact with organic materials or reducing agents.)7.3 Oxygen, 99.5 % PureCompre
32、ssed gas contained in a cylinder equipped with a suitable pressure regulator and a needlevalve to control gas flow. (WarningPure oxygen vigorously accelerates combustion. Verify all regulators, lines, and valves arefree of grease and oil.)7.4 Reference Materials, Reference Material (RM)that are coal
33、(s) or coke(s) prepared by a national metrology body. Othermaterials that are coal(s) or coke(s) with documented traceability to reference material (CRM) coal(s) or coke(s) prepared by anational metrology body can also be used. Only use material(s) with an assigned value and assigned uncertainty for
34、 sulfur. Theuncertainty expressed as the confidence interval of the assigned value shall be less than the repeatability specified in the appropriatesection on Precision and Bias of this test method.7.4.1 To minimize problems with instrument calibration or calibration verification mix all reference m
35、aterial before removingthe test portion from the container. Do not use the reference material for calibration or calibration verification when less than 2g remain in the container. The remaining material can be used for instrument conditioning.7.5 BBOT (2,5-di(5-tert-butylbenzoxazol-2-yl)thiophene,
36、C26H26N2O2S)A pure substance and certified reference material forsulfur (7.47 % sulfur).4 Reagent Chemicals, American Chemical Society Specifications , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standar
37、ds for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.FIG. 2 Apparatus for the Determination of Sulfur by the Infrared Detection, Method BD4239 1337.6 Tungsten Oxide (WO3)A combu
38、stion promoter and a fluxing agent. (WarningTungsten Oxide is a strong oxidizingagent.)8. Procedure8.1 Instrument PreparationPerform apparatus set up system checks in accordance with manufacturers instructions.8.1.1 Balance CalibrationCalibrate the instrument balance in accordance with manufacturers
39、 instructions.8.2 Calibration of the Infrared Detection SystemIf the instrument has been previously calibrated in accordance with thesection on instrument calibration, proceed to the Analysis Procedure, otherwise carry out a calibration as specified in the sectionon instrument calibration.following
40、section.8.2.1 Calibration with Coal and Coke Certified Reference MaterialsSelect reference materials (7.4), in the range of thesamples to be analyzed. Use at least three such reference materials, for each range of sulfur values to be tested. Select one referencematerial containing at least as much s
41、ulfur as the highest level of sulfur expected. Select two additional reference materials, oneapproximately at the mid-point of the range and one below the lowest level of sulfur expected.8.2.1.1 Use a mass of material recommended by the apparatus manufacturer to carry out a minimum of three determin
42、ationsto condition the equipment before calibration. Use a material with a sulfur value near the mid point of the expected calibrationrange.8.2.1.2 For each reference material coal or coke employed for calibration, use the as-determined sulfur value previouslycalculated from the certified dry-basis
43、sulfur value and residual moisture determined using either Test Methods D3173 or D7582or ISO 11722. Use a mass of material and the calibration procedure recommended by the apparatus manufacturer. Weigh to at leastthe nearest 1 mg and evenly spread the test portion of the reference material into the
44、sample combustion boat (6.4). Position thesample in the hot zone of the furnace until the instrument returns to baseline as indicated according to settings recommended bythe manufacturer. If the analysis time exceeds the maximum analysis time recommended by the manufacturer take corrective actionas
45、recommended by the manufacturer.8.2.2 Calibration with BBOTTo meet the precision requirements of this method, six calibration points are required for a linearfit and eight calibration points are required for a nonlinear fit.Acalibration point consists of a determination on a single test portionof ca
46、libration material. Select test portions of the calibrant that have at least as much sulfur as the highest level of sulfur expected,test portions of the calibrant that have as much sulfur as the lowest level of sulfur expected and test portions spread evenly inbetween the highest and lowest levels o
47、f sulfur.8.2.2.1 The mass of the calibrant needed can be calculated using the following equation: (Note 1).MC 5MT 3 SAD!SC(1)WhereMC = Mass of calibrantMT = Mass normally used for test samplesSAD = Percent sulfur (as-determined) in the test sampleSC = Percent sulfur in the pure substance calibrantNO
48、TE 1In the interlaboratory study that yielded the data for the precision statement for this method, the mass of BBOT used for calibration rangedfrom about 15 mg to over 80 mg. Some analyzers may use larger amounts. Amounts less than 15 mg BBOT should only be measured on a five-placeanalytical balanc
49、e.8.2.3 Calibration VerificationCarry out a minimum of three determinations to condition the equipment before calibrationverification (see 8.2.1.1). Verify the instrument calibration prior to analyzing test samples, upon completion of all test samples andas needed to meet quality control requirements.Analyze a test portion of reference material(s) (7.4) using the apparatus conditionsemployed for instrument calibration (8.2.1). Use a mass that does not exceed the maximum mass used for instrument calibrationand with a sulfur value wit
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