1、Designation: D4239 131D4239 14Standard 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, i
2、n 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 U.S. Department of Defense.1 NOTEFo
3、otnote 6 was corrected editorially in November 2013.1. Scope1.1 This 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
4、 an instrumental method.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 All percentages are percent mass fractions unless otherwise noted.1.5 This standard does not purport to address all of the safety concerns, if any
5、, 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:2D346 Practice for Collection and Preparation of Coke S
6、amples for Laboratory AnalysisD2013 Practice for Preparing Coal Samples for AnalysisD3173 Test Method for Moisture in the Analysis Sample of Coal and CokeD3176 Practice for Ultimate Analysis of Coal and CokeD3180 Practice for Calculating Coal and Coke Analyses from As-Determined to Different BasesD7
7、448 Practice for Establishing the Competence of Laboratories UsingASTM Procedures in the Sampling andAnalysis of Coaland CokeD7582 Test Methods for Proximate Analysis of Coal and Coke by Macro Thermogravimetric AnalysisE691 Practice for Conducting an Interlaboratory Study to Determine the Precision
8、of a Test Method2.2 ISO Standard:3ISO 11722 Solid Mineral Fuels-Hard Coal Determination of Moisture in the general analysis test sample 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 combustiontub
9、e operating temperature of 1350C in a stream of oxygen. During combustion at temperatures above 1350 C, the sulfur andsulfur compounds contained in the sample are decomposed and oxidized almost exclusively to gaseous sulfur dioxide, SO2.Moisture and particulates are removed from the gas by filters.
10、The gas stream is passed through a cell in which sulfur dioxide ismeasured by an infrared (IR) absorption detector. Sulfur dioxide absorbs 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:
11、thus, at the detector, lessenergy is received.All other IR energy is eliminated from reaching the detector by a precise wavelength filter. Thus, the absorption1 This test method is under the jurisdiction of ASTM Committee D05 on Coal and Coke and is the direct responsibility of Subcommittee D05.21 o
12、n Methods of Analysis.Current edition approved Oct. 1, 2013March 1, 2014. Published October 2013March 2014. Originally approved in 1983. Last previous edition approved in 20122013 asD4239 12.D4239 131. DOI: 10.1520/D4239-13.10.1520/D4239-14.2 For referencedASTM standards, visit theASTM website, www.
13、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, Case postale 56, CH-121
14、1, 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 all changes accurately,
15、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 19428-2959. United States1of I
16、R 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 procedure for Method A uses coal or
17、 coke reference materials to calibrate the sulfur analyzer. A second procedurefor Method A uses a pure substance, BBOT, to calibrate the sulfur analyzer.3.2 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
18、weight of tungsten trioxide (WO3). Sulfur is oxidized during the reaction of the sample and WO3.The tube furnace is operated at a minimum combustion tube operating temperature of 1150C and tin (Sn) sample boats areutilized. Moisture and particulates are removed from the combustion gas by filters. Th
19、e gas stream is then passed through a cellin which sulfur dioxide is measured by an infrared (IR) absorption detector. Sulfur dioxide absorbs 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
20、: thus, at the detector, less energy is received. All other IR energy is eliminated from reaching the detector by a precisewavelength filter. 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 cel
21、l is used as both a reference and a measurement chamber. Total sulfur as sulfurdioxide is detected on a continuous basis.4. Significance 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, ev
22、aluation of potential sulfuremissions from coal and coke combustion or conversion processes, and evaluation of coal and coke quality in 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 th
23、rough reference to Practice D7448.5. Sample5.1 Pulverize the sample to pass No. 60 (250-m) sieve and mix thoroughly in accordance with 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
24、for calculations to other than the as-determined basis.5.3 Procedures for calculating as-determined sulfur values obtained from the analysis sample to other bases are described inPractices D3176 and D3180.6. ApparatusCombustion Method A (1350C)6.1 Measurement ApparatusEquipped to combust the sample
25、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) to at least 1350C.It is normally heated electrically using resistance rods, a resistance wire, or molybdenum disilicide elements. Specific dimensionscan vary with m
26、anufacturers design.6.3 Combustion TubeMade 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 ma
27、terials.6.4 Sample Combustion Boats, made 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.6.6 BalanceA stand-a
28、lone balance or a balance integrated with the instrument, with a resolution of at least 0.1% relative ofthe test portion mass.Combustion Method B (1150C)6.7 Measurement ApparatusEquipped to combust the sample as described in 3.2 (See Fig. 2)6.8 Tube FurnaceCapable of heating the hot zone or outer su
29、rface of the combustion tube, or both (6.86.9) to at least 1150C.It is normally heated electrically using resistance wire. Specific dimensions can vary with manufacturers design.6.9 Combustion TubeMade of quartz with provisions for routing the gases produced by combustion through the infrared cell.6
30、.10 Sample Combustion BoatMade of an iron-free tin material and of a convenient size suitable for the dimensions of thecombustion tube.D4239 1427. Reagents7.1 Purity of ReagentsUse reagent grade chemicals in all tests. Unless otherwise indicated, it is intended that all reagentsconform to the specif
31、ications 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 sufficiently high purity to permit its usewithout lessening the accuracy of the determination.7.2 Magn
32、esium 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 % PureCompressed gas contained in a cylinder equipped with a suitable pressure regulator and a needlevalve to c
33、ontrol 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(s) or coke(s) prepared by a national metrology body. Othermaterials that are coal(s) or coke(s) wi
34、th 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 sulfur. Theuncertainty expressed as the confidence interval of the assigned value shall be less th
35、an the repeatability specified in the appropriatesection on Precision and Bias of this test method.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 Ana
36、lar Standards 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. 1 Apparatus for the Determination of Sulfur by the Infrared Detection, Method AFIG. 2 Apparatus for the Dete
37、rmination of Sulfur by the Infrared Detection, Method BD4239 1437.4.1 To minimize problems with instrument calibration or calibration verification mix all reference material before removingthe test portion from the container. Do not use the reference material for calibration or calibration verificat
38、ion 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, C26H26N2O2S)A pure substance and certified reference material forsulfur (7.47 % sulfur).7.6 Tungsten Oxide (WO3)A combustion promoter
39、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 instructions.8
40、.2 Calibration of the Infrared Detection SystemIf the instrument has been previously calibrated in accordance with thesection on instrument calibration, proceed to theAnalysis Procedure, otherwise carry out a calibration as specified in the followingsection.8.2.1 Calibration with Coal and Coke Certi
41、fied 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 sulfur as the highest level of sulfur expected. Sel
42、ect 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 determinationsto condition the equipment before calibratio
43、n. Use a material with a sulfur value near the mid point of the expected calibrationrange.8.2.1.2 For each reference coal or coke employed for calibration, use the as-determined sulfur value previously calculated fromthe certified dry-basis sulfur value and residual moisture determined using either
44、Test Methods D3173 or D7582 or ISO 11722.Use a mass of material and the calibration procedure recommended by the apparatus manufacturer. Weigh to at least the nearest1 mg and evenly spread the test portion of the reference material into the sample combustion boat (6.4). Position the sample inthe hot
45、 zone of the furnace until the instrument returns to baseline as indicated according to settings recommended by themanufacturer. If the analysis time exceeds the maximum analysis time recommended by the manufacturer take corrective actionas recommended by the manufacturer.8.2.2 Calibration with BBOT
46、To 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 calibration material. Select test portions of the calibrant t
47、hat 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 of sulfur.8.2.2.1 The mass of the calibrant needed can be ca
48、lculated 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 calibrantNOTE 1In the interlaboratory study that yielded the data for
49、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 balance.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 req
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