1、Designation: D4239 141Standard 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.1NOTESummary of
3、Changes added and Tables 3 and A1.4 corrected editorially in November 2014.1. 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 metho
4、d canbe classified as an instrumental method.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 All percentages are percent mass fractions unless other-wise noted.1.5 This standard does not purport to address all of thesafe
5、ty concerns, if 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:2D346 Practice for Collection and
6、 Preparation of CokeSamples for Laboratory AnalysisD2013 Practice for Preparing Coal Samples for AnalysisD3173 Test Method for Moisture in the Analysis Sample ofCoal and CokeD3176 Practice for Ultimate Analysis of Coal and CokeD3180 Practice for Calculating Coal and Coke Analysesfrom As-Determined t
7、o 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 Thermogravimetric AnalysisE691 Practice for Conducting an Interlaboratory Study toDete
8、rmine the Precision of a Test Method2.2 ISO Standard:3ISO 11722 Solid Mineral Fuels-Hard Coal Determinationof Moisture in the general analysis test sample by dryingin nitrogen3. Summary of Test Method3.1 Combustion Method A (1350C)A weighed test por-tion of sample is burned in a tube furnace at a mi
9、nimumcombustion tube operating temperature of 1350C in a streamof oxygen. During combustion at temperatures 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 the
10、gas by filters. The gas stream is passed through a cell in whichsulfur dioxide is measured by an infrared (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 bei
11、ngtransmitted: thus, at the detector, less energy is received. Allother IR energy 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 detect
12、or. One cell isused as both a reference and a measurement chamber. Totalsulfur 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, tocal
13、ibrate the sulfur analyzer.1This test method is under the jurisdiction of ASTM Committee D05 on Coaland Coke and is the direct responsibility of Subcommittee D05.21 on Methods ofAnalysis.Current edition approved March 1, 2014. Published March 2014. Originallyapproved in 1983. Last previous edition a
14、pproved in 2013 as D4239 131. DOI:10.1520/D4239-14.2For 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.3Available
15、 from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, 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
16、, PA 19428-2959. United States13.2 Combustion Method B (1150C)A weighed test por-tion 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 operat
17、ed at a minimumcombustion tube operating temperature of 1150C and tin (Sn)sample 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. Sulf
18、ur dioxide absorbsIR energy at a precise wavelength within the IR spectrum.Energy 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 wa
19、velength filter. Thus, theabsorption of IR energy can be attributed only to sulfur 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. Si
20、gnificance 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 ofcoal preparation and cleaning, evaluation of potential sulfuremissions from coal and coke combustion or conversionprocesses, and evaluation of coal and coke qua
21、lity in relation tocontract specifications, as well as for scientific purposes.4.3 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 No. 60 (250-m) sieve andmix thoroughly in accordance w
22、ith Practice D2013 or PracticeD346.5.2 Analyze a separate portion of the analysis sample formoisture content in accordance with Test Method D3173,orD7582 or ISO 11722 for calculations to other than theas-determined basis.5.3 Procedures for calculating as-determined sulfur valuesobtained from the ana
23、lysis sample to other bases are describedin Practices D3176 and D3180.6. ApparatusCombustion Method A (1350C)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) t
24、o at least 1350C.It is normally heated electrically using resistance rods, aresistance wire, or molybdenum disilicide elements. Specificdimensions can vary with manufacturers design.6.3 Combustion TubeMade of mullite, porcelain, or zirconwith provisions for routing the gases produced by combustionth
25、rough the infrared cell. The tube may have a boat stop madeof reticulated ceramics heated to 1350C that serves to com-plete the combustion of sulfur containing materials.6.4 Sample Combustion Boats, made of iron-free materialand of a convenient size suitable for the dimensions of thecombustion tube.
26、FIG. 1 Apparatus for the Determination of Sulfur by the Infrared Detection, Method AD4239 14126.5 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 i
27、nstrument, with a resolution of at least 0.1% relativeof the test portion mass.Combustion Method B (1150C)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
28、 least 1150C.It is normally heated electrically using resistance wire. Specificdimensions 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 tinmater
29、ial and of a convenient size suitable for the dimensions 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 Che
30、mical Society, where suchspecifications are available.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 oxidiz
31、ing agent. Do not regenerate theabsorbent. Do not 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 combusti
32、on. Verify all regulators, lines,and valves are 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
33、(s)prepared by a national metrology body can also 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 repeatabilityspecified in the appropriate section on Precision an
34、d Bias ofthis test method.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 co
35、ntainer. The remainingmaterial 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 O
36、xide is a strong oxidiz-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 Dete
37、ction SystemIf theinstrument 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.8.2.1 Calibration with Coal and Coke Certified ReferenceMaterialsSelect refere
38、nce materials (7.4), in the range of thesamples to be analyzed. Use at least three such reference4Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar
39、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 for the Determination of Sulfur by the Infrared Detection, Method BD4239 1413materials, for each range
40、 of sulfur values to be tested. 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 m
41、aterial recommended by the appa-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
42、 the as-determined sulfur value previouslycalculated from the certified dry-basis sulfur value and residualmoisture determined using either Test Methods D3173 orD7582 or ISO 11722. Use a mass of material and thecalibration procedure recommended by the apparatus manufac-turer. Weigh to at least the n
43、earest 1 mg and evenly spread thetest portion of the reference material into the sample combus-tion boat (6.4). Position the sample in the hot zone of thefurnace until the instrument returns to baseline as indicatedaccording to settings recommended by the manufacturer. If theanalysis time exceeds th
44、e maximum analysis time recom-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 anonlin
45、ear fit. A calibration point 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 sulfu
46、r expected and testportions 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)WhereMC= Mass of calibrantMT= Mass normally used for test samplesSAD= Percent sulfur (as-determ
47、ined) in the test sampleSC= Percent sulfur in the pure substance calibrantNOTE 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. Some analyzers mayuse larger amounts.8.2.3 Calibr
48、ation VerificationCarry out a minimum ofthree determinations to condition the equipment before cali-bration verification (see 8.2.1.1). Verify the instrument calibra-tion prior to analyzing test samples, upon completion of all testsamples and as needed to meet quality control requirements.Analyze a
49、test portion of reference material(s) (7.4) using theapparatus conditions employed for instrument calibration(8.2.1). Use a mass that does not exceed the maximum massused for instrument calibration and with a sulfur value withinthe range of the instrument calibration. If the value determinedfor each reference material employed for verification is notwithin the specified uncertainty for the assigned sulfur valuerepeat the instrument calibration in accordance with 8.2.1.Repeat all samples analyzed since the last successful calibra-
