1、Designation: D4239 181Standard 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 the ca
2、se 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.1NOTETable 1 was
3、 corrected editorially in October 2018.1. Scope*1.1 This test method covers the determination of sulfur insamples of coal or coke by high-temperature tube furnacecombustion.1.1.1 Two analysis methods are described.1.2 When automated equipment is used, either method canbe classified as an instrumenta
4、l method.1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses after SI units areprovided for information only and are not considered standard.1.4 All percentages are percent mass fractions unless other-wise noted.1.5 This standard does not purport to addre
5、ss all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was develo
6、ped in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Docum
7、ents2.1 ASTM Standards:2D346/D346M Practice for Collection and Preparation ofCoke Samples for Laboratory AnalysisD2013/D2013M Practice for Preparing Coal Samples forAnalysisD3173/D3173M Test Method for Moisture in the AnalysisSample of Coal and CokeD3176 Practice for Ultimate Analysis of Coal and Co
8、keD3180 Practice for Calculating Coal and Coke Analysesfrom As-Determined to Different BasesD7448 Practice for Establishing the Competence of Labora-tories Using ASTM Procedures in the Sampling andAnalysis of Coal and CokeD7582 Test Methods for Proximate Analysis of Coal andCoke by Macro Thermogravi
9、metric AnalysisE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standard:3ISO 5725-6 Accuracy (trueness and precision) of measure-ment methods and resultsPart 6: Use in practice ofaccuracy valuesISO 11722 Solid mineral fuelsHard coalDeterminatio
10、nof moisture in the general analysis test sample by dryingin nitrogen3. Summary of Test Method3.1 Combustion Method A (1350 C)A weighed test por-tion of sample is burned in a tube furnace at a minimumcombustion tube operating temperature of 1350 C in a streamof oxygen. During combustion at temperatu
11、res above 1350 C,the sulfur and sulfur compounds contained in the sample aredecomposed and oxidized almost exclusively to gaseous sulfurdioxide, SO2. Moisture and particulates are removed from thegas by filters. The gas stream is passed through a cell in whichsulfur dioxide is measured by an infrare
12、d (IR) absorptiondetector. Sulfur dioxide absorbs IR energy at a precise wave-length within the IR spectrum. Energy is absorbed as the gaspasses through the cell body in which the IR energy is being1This test method is under the jurisdiction of ASTM Committee D05 on Coaland Coke and is the direct re
13、sponsibility of Subcommittee D05.21 on Methods ofAnalysis.Current edition approved Sept. 1, 2018. Published October 2018. Originallyapproved in 1983. Last previous edition approved in 2017 as D4239 17. DOI:10.1520/D4239-18E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orco
14、ntact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Swi
15、tzerland, http:/www.iso.ch.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized princip
16、les on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1transmitted: thus, at the detector, less energy is received. Allother IR ener
17、gy is eliminated from reaching the detector by aprecise wavelength filter. Thus, the absorption of IR energy canbe attributed only to sulfur dioxide whose concentration isproportional to the change in energy at the detector. One cell isused as both a reference and a measurement chamber. Totalsulfur
18、as sulfur dioxide is detected on a continuous basis.3.1.1 One procedure for Method A uses coal or cokereference materials to calibrate the sulfur analyzer. A secondprocedure for Method A uses a pure substance, BBOT, tocalibrate the sulfur analyzer.3.2 Combustion Method B (1150 C)A weighed test por-t
19、ion of sample is burned in a quartz combustion tube in astream of oxygen with an equal or excess weight of tungstentrioxide (WO3). Sulfur is oxidized during the reaction of thesample and WO3. The tube furnace is operated at a minimumcombustion tube operating temperature of 1150 C and tin (Sn)sample
20、boats are utilized. Moisture and particulates are re-moved from the combustion gas by filters. The gas stream isthen passed through a cell in which sulfur dioxide is measuredby an infrared (IR) absorption detector. Sulfur dioxide absorbsIR energy at a precise wavelength within the IR spectrum.Energy
21、 is absorbed as the gas passes through the cell body inwhich the IR energy is being transmitted: thus, at the detector,less energy is received. All other IR energy is eliminated fromreaching the detector by a precise wavelength filter. Thus, theabsorption of IR energy can be attributed only to sulfu
22、r dioxidewhose concentration is proportional to the change in energy atthe detector. One cell is used as both a reference and ameasurement chamber. Total sulfur as sulfur dioxide is de-tected on a continuous basis.4. Significance and Use4.1 Sulfur is part of the ultimate analysis of coal and coke.4.
23、2 Results of the sulfur analysis are used for evaluation ofcoal preparation and cleaning, evaluation of potential sulfuremissions from coal and coke combustion or conversionprocesses, and evaluation of coal and coke quality in relation tocontract specifications, as well as for scientific purposes.4.
24、3 The competency of laboratories with respect to use ofthis standard can be established through reference to PracticeD7448.5. Sample5.1 Pulverize the sample to pass 250 m (No. 60) sieve andmix thoroughly in accordance with Practice D2013/D2013M orPractice D346/D346M.5.2 Analyze a separate portion of
25、 the analysis sample formoisture content in accordance with Test Method D3173/D3173M, or Test Methods D7582 or ISO 11722 for calcula-tions to other than the as-determined basis.5.3 Procedures for calculating as-determined sulfur valuesobtained from the analysis sample to other bases are describedin
26、Practices D3176 and D3180.6. ApparatusCombustion Method A (1350 C)6.1 Measurement ApparatusEquipped to combust thesample as described in 3.1 (see Fig. 1).6.2 Tube FurnaceCapable of heating the hot zone or outersurface of the combustion tube, or both (6.3) to at least1350 C. It is normally heated ele
27、ctrically using resistancerods, a resistance wire, or molybdenum disilicide elements.Specific dimensions can vary with manufacturers design.6.3 Combustion TubeMade of mullite, porcelain, or zirconwith provisions for routing the gases produced by combustionFIG. 1 Apparatus for Determination of Sulfur
28、 by Infrared Detection, Method AD4239 1812through the infrared cell. The tube may have a boat stop madeof reticulated ceramics heated to 1350 C that serves tocomplete the combustion of sulfur containing materials.6.4 Sample Combustion Boats, made of iron-free materialand of a convenient size suitabl
29、e for the dimensions of thecombustion tube.6.5 Boat PullerWhere required, a rod of a heat-resistantmaterial with a bent or disk end to insert and remove boatsfrom the combustion tube.6.6 BalanceA stand-alone balance or a balance integratedwith the instrument, with a resolution of at least 0.3 % rela
30、tiveof the test portion mass.Combustion Method B (1150 C)6.7 Measurement ApparatusEquipped to combust thesample as described in 3.2 (see Fig. 2).6.8 Tube FurnaceCapable of heating the hot zone or outersurface of the combustion tube, or both (6.9) to at least1150 C. It is normally heated electrically
31、 using resistancewire. Specific dimensions can vary with manufacturers design.6.9 Combustion TubeMade of quartz with provisions forrouting the gases produced by combustion through the infraredcell.6.10 Sample Combustion BoatMade of an iron-free tinmaterial and of a convenient size suitable for the d
32、imensions ofthe combustion tube.7. Reagents7.1 Purity of ReagentsUse reagent grade chemicals in alltests. Unless otherwise indicated, it is intended that all reagentsconform to the specifications of the Committee on AvailableReagents of the American Chemical Society, where suchspecifications are ava
33、ilable.4Other grades can be used, pro-vided it is first ascertained the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of thedetermination.7.2 Magnesium Perchlorate(WarningMagnesium per-chlorate is a strong oxidizing agent. Do not regenerate theabsorbent. Do n
34、ot allow contact with organic materials orreducing agents.)7.3 Oxygen, 99.5 % PureCompressed gas contained in acylinder equipped with a suitable pressure regulator and aneedle valve to control gas flow. (WarningPure oxygenvigorously accelerates combustion. Verify all regulators, lines,and valves are
35、 free of grease and oil.)7.4 Reference Materials, Reference Material (RM)that arecoal(s) or coke(s) prepared by a national metrology body.Other materials that are coal(s) or coke(s) with documentedtraceability to reference material (CRM) coal(s) or coke(s)prepared by a national metrology body can al
36、so be used. Onlyuse material(s) with an assigned value and assigned uncertaintyfor sulfur. The uncertainty expressed as the confidence intervalof the assigned value shall be less than the reproducibilitystandard deviation SRspecified in the appropriate section onPrecision and Bias of this test metho
37、d.7.4.1 To minimize problems with instrument calibration orcalibration verification mix all reference material before re-moving the test portion from the container. Do not use thereference material for calibration or calibration verificationwhen less than 2 g remain in the container. The remainingma
38、terial 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 ma-terial for sulfur (7.47 % sulfur).7.6 Tungsten Oxide (WO3)A combustion promoter and afluxing agent. (WarningTungsten Oxide is a strong oxidiz-
39、ing agent.)8. Procedure8.1 Instrument PreparationPerform apparatus set up sys-tem checks in accordance with manufacturers instructions.8.1.1 Balance CalibrationCalibrate the instrument bal-ance in accordance with manufacturers instructions.8.2 Calibration of the Infrared Detection SystemIf theinstru
40、ment has been previously calibrated in accordance withthe section on instrument calibration, proceed to the AnalysisProcedure, otherwise carry out a calibration as specified in thefollowing section.4Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, D
41、C. 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), Rockville,MD.FIG. 2 Apparatus f
42、or Determination of Sulfur by Infrared Detection, Method BD4239 18138.2.1 Calibration with Coal and Coke Certified ReferenceMaterialsSelect reference materials (7.4), in the range of thesamples to be analyzed. Use at least three such referencematerials, for each range of sulfur values to be tested.
43、Selectone reference material containing at least as much sulfur as thehighest level of sulfur expected. Select two additional refer-ence materials, one approximately at the mid-point of the rangeand one below the lowest level of sulfur expected.8.2.1.1 Use a mass of material recommended by the appa-
44、ratus manufacturer to carry out a minimum of three determi-nations to condition the equipment before calibration. Use amaterial with a sulfur value near the mid point of the expectedcalibration range.8.2.1.2 For each reference coal or coke employed forcalibration, use the as-determined sulfur value
45、previouslycalculated from the certified dry-basis sulfur value and residualmoisture determined using either Test Methods D3173/D3173M, D7582, or ISO 11722. Use a mass of material and thecalibration procedure recommended by the apparatus manufac-turer. Weigh in accordance with section 6.6 and evenly
46、spreadthe test portion of the reference material into the samplecombustion boat (6.4). Position the sample in the hot zone ofthe furnace until the instrument returns to baseline as indicatedaccording to settings recommended by the manufacturer. If theanalysis time exceeds the maximum analysis time r
47、ecom-mended by the manufacturer take corrective action as recom-mended by the manufacturer.8.2.2 Calibration with BBOTTo meet the precision re-quirements of this method, six calibration points are requiredfor a linear fit and eight calibration points are required for anonlinear fit. A calibration po
48、int consists of a determination ona single test portion of calibration material. Select test portionsof the calibrant that have at least as much sulfur as the highestlevel of sulfur expected, test portions of the calibrant that haveas much sulfur as the lowest level of sulfur expected and testportio
49、ns spread evenly in between the highest and lowest levelsof sulfur.8.2.2.1 The mass of the calibrant needed can be calculatedusing the following equation: (Note 1).MC5MT3 SAD!SC(1)where:MC= Mass of calibrant,MT= Mass normally used for test samples,SAD= Percent sulfur (as-determined) in the test sample, andSC= Percent sulfur in the pure substance calibrant.NOTE 1In the interlaboratory study that yielded the data for theprecision statement for this method, the mass of BBOT used forcalibration ranged from about 15 mg to over 80 mg. S
