ASTM_D_5263_-_15.pdf

Designation:D526315Standard 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 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.1.Scope1.1 This colorimetric test method describes the determina-tion of the relative degree of oxidation by alkali 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 units 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 regulatory 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 that 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 solution 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 only intended to serve asa guide to the supplier,buyer,and user for selecting coals formetallurgical use.NOTE1Lower rank bituminous coals are more easily extracted thanhigher rank coal.6.Apparatus6.1 Transmission SpectrophotometerSingle-beam,gratingspectrophotometer having a wavelength range of 340 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 measuring 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 Octylphenoxypolyethoxyethanol 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 edition 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 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 States1 8.Calibration and Standardization8.1 Optical light filters with known absorbance/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,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 out 1 g(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.9.4 Add 100 mL of NaOH solution and one drop of wettingagent(100%concentration)to the coal.Place a glass stirringrod into the beaker.NOTE2Wetting agent drop size can significantly influence results,with larger drop size causing lower transmittances.9.5 Place beaker(s)onto a preheated hot plate 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 thermomete