1、Designation: D5263 15Standard Test Method forDetermining the Relative Degree of Oxidation in BituminousCoal by Alkali Extraction1This standard is issued under the fixed designation D5263; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, 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.1. Scope1.1 This colorimetric test method describes the determina-tion of the relative degree of oxidation by alk
3、ali extraction ofcoals that are high volatile A bituminous to low volatilebituminous in rank.1.2 This test cannot be sensitive to thermally oxidized coal.It is intended for coals that may be oxidized as a result ofweathering.1.3 The values stated in SI units are to be regarded asstandard. No other u
4、nits of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety 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 re
5、gulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD7448 Practice for Establishing the Competence of Labora-tories Using ASTM Procedures in the Sampling andAnalysis of Coal and Coke3. Terminology3.1 There are no terms in this standard th
6、at require new orother than dictionary definitions.4. Summary of Test Method4.1 Humic acids, which are present in oxidized coals, areextracted from the coal with sodium hydroxide solution. Thedegree of oxidation is determined by colorimetrically measur-ing the transmittance of the alkali extract sol
7、ution at 520 nm.The intensity of the color produced by the humic acids is afunction of the degree of oxidation.5. Significance and Use5.1 This test method is a relative measure of the degree ofoxidation present in coal. It does not determine the quantitativeamount of oxidized coal present. It is onl
8、y intended to serve asa guide to the supplier, buyer, and user for selecting coals formetallurgical use.NOTE 1Lower rank bituminous coals are more easily extracted thanhigher rank coal.6. Apparatus6.1 Transmission SpectrophotometerSingle-beam, gratingspectrophotometer having a wavelength range of 34
9、0 to 900nm.6.2 Glass Test Tubes/Cuvettes, with light paths ranging from10 to 17 mm may be used. Test tubes with an inside diameterof 17 6 0.3 mm are commonly used.6.3 Analytical Balance, sensitive to 0.001 g.6.4 Hot Plate, capable of bringing aqueous solutions to aboil.6.5 Thermometer, capable of me
10、asuring up to 100C with asensitivity of 60.5C.6.6 Filter Papers, Type II, Class F and G.6.7 Timer, capable of measuring 30 min to the nearestsecond.6.8 Graduated Cylinder, 100-mL capacity.6.9 Beakers, 400-mL capacity.7. Reagents7.1 Sodium Hydroxide Solution (certified 1N).7.2 Octylphenoxypolyethoxye
11、thanol Nonionic SurfactantWetting agent.7.2.1 Wetting agent shall not be diluted (100 % concentra-tion).1This test method is under the jurisdiction of ASTM Committee D05 on Coaland Coke and is the direct responsibility of Subcommittee D05.15 on MetallurgicalProperties of Coal and Coke.Current editio
12、n approved Jan. 1, 2015. Published January 2015. Originallypublished approved in 1992. Last previous edition approved in 2008 asD5263 93(2008)1. DOI: 10.1520/D5263-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual
13、Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States18. Calibration and Standardization8.1 Optical light filters with known absorbanc
14、e/transmissionshall be used to check wavelength accuracy and linearity of thespectrophotometer. Solutions with accurate absorbance valuescan be found in published literature.38.2 A blank solution consisting of 100 mL of 1N sodiumhydroxide is prepared by following the procedure outlined inSection 9,
15、except coal is not used.9. Procedure9.1 Activate the spectrophotometer and set at 520-nm wave-length; allow sufficient time for the instrument to stabilize(30 min).9.2 Weigh out1g(60.01 g) of the 250-m (No. 60 U.S.Standard Sieve Series) coal sample.9.3 Transfer the coal to a standard 400-mL beaker.9
16、.4 Add 100 mL of NaOH solution and one drop of wettingagent (100 % concentration) to the coal. Place a glass stirringrod into the beaker.NOTE 2Wetting agent drop size can significantly influence results,with larger drop size causing lower transmittances.9.5 Place beaker(s) onto a preheated hot plate
17、 and place athermometer in the beaker.9.6 Bring temperature of the contents to 98C. It shall take3 to 4 min to reach a boil, depending on the number of beakerson the hot plate. When measuring the temperature of the blanksolution or test solution, or both, suspend the thermometer in amanner such that
18、 the temperature of the solution and not thetemperature of the beaker resting on top of the hot plate isbeing measured.9.7 At the time the blank solution or test solution, or both,in the beakers reaches the temperature of 98C, set the timerfor 3 min. Allow the solution to boil for 3 min, stirring th
19、econtents for at least 5 s for each 1-min interval.9.8 After the 3-min boil, carefully remove hot beakers andallow to cool under ambient conditions for 30 min. This is alsodetermined by using a timer.9.9 Filter (by gravity) the entire blank solution or testsolution, or both, on a stack of one Type I
20、I Class F filter paperon top of one Type II Glass G filter paper. Filter the slurry intoa 100-mL graduated cylinder, making sure funnel and gradu-ated cylinder are dry before each test. After filtration, adddeionized (distilled) water (Type II, Specification D1193)tothe cylinder to bring the solutio
21、n to 80 mL and stir with a glassrod.NOTE 3The beaker should not be rinsed onto the filter paper. It is notsignificant if some coal remains in the beaker.9.10 Adjust the 0 and 100 % transmittance levels of thespectrophotometer.9.10.1 Adjust the spectrophotometer to read zero by closingthe lid of the
22、sample/tube holder assembly of the instrument.9.10.2 Fill cuvette/test tube with the blank solution andinsert into the spectrophotometer.9.10.3 Adjust the spectrophotometer to read 100 % trans-mittance by inserting the blank solution (see 8.2).9.10.4 Periodically during the analysis, check the span
23、(0and 100 % transmittance) to be sure that the instrument has notdrifted.9.11 Place the cuvette/test tube containing the test solutioninto the spectrophotometer; measure and record the percenttransmittance of each test solution. Use only cuvette/test tubesfor the test solution that yield the same tr
24、ansmittance values asthe cuvettes/test tubes used with the blank solutions.10. Calculation10.1 Since the light path is a variable in this test, resultsmust be adjusted to a common basis to make comparisons. A17-mm light path will be used. Thus, if the test was performedusing any other light path tha
25、n 17 mm, the result must beadjusted to the 17-mm light path using Beers law.10.2 Adjust results as follows:Ax52LogSTx100D(1)A175 Ax17 mm/bx! (2)T175 102A17! 3100 (3)where:Tx= transmittance obtained by analysis, %;Ax= absorbance corresponding to Tx;bx= test light path, mm;A17= absorbance at 17-mm lig
26、ht path; andT17= transmittance (calculated) at 17-mm light path.11. Report11.1 Report the value T17(obtained in Section 9).11.2 All accountability and quality control aspects of GuideD7448 apply to this test method.12. Precision and Bias12.1 PrecisionThe relative precision of this test methodfor the
27、 determination of the degree of oxidation of bituminouscoal covers the range (percent transmittance) from 55 to 98 %.12.1.1 RepeatabilityThe difference in absolute values be-tween two consecutive tests conducted on the same sample inthe same laboratory by the same operator using the sameapparatus sh
28、ould not exceed the repeatability interval I(r) more3Mellon, M. G., Analytical Absorption Spectroscopy, John Wiley alkali extraction; colorimetric; humic ac-ids; oxidation (weathering); transmittanceASTM International takes no position respecting the validity of any patent rights asserted in connect
29、ion with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsibl
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31、ideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 B
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