ASTM_D_4208_-_13.pdf

Designation:D420813Standard Test Method forTotal Chlorine in Coal by the Oxygen Bomb Combustion/IonSelective Electrode Method1This standard is issued under the fixed designation D4208;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.Scope*1.1 This test method covers the analysis of total chlorine incoal.1.2 UnitsThe values stated in SI units are to be regardedas standard.No other units of measurement are included in thisstandard.1.3 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:2D121 Terminology of Coal and CokeD1193 Specification for Reagent WaterD3173 Test Method for Moisture in the Analysis Sample ofCoal and CokeD3180 Practice for Calculating Coal and Coke Analysesfrom As-Determined to Different BasesE144 Practice for Safe Use of Oxygen Combustion BombsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 For definitions of terms used in this test method,refer toTerminology D121.4.Summary of Test Method4.1 Total chlorine is determined in this method by combus-ting a weighed sample in an oxygen bomb with dilute baseadsorbing the chlorine vapors.The bomb is rinsed into a beakerwith water and following the addition of an ionic strengthadjuster,the chloride is determined by ion-selective electrode.5.Significance and Use5.1 The purpose of this test method is to measure the totalchlorine content of coal.The chlorine content of coals may beuseful in the evaluation of slagging problems,corrosion inengineering processes,and in the total analysis of coal andcoke.When coal samples are combusted in accordance withthis method,the chlorine is quantitatively retained and isrepresentative of the total chlorine content of the whole coal.6.Apparatus6.1 Combustion Bomb,constructed of materials that are notaffected by the combustion process or products.The bombmust be designed so that all liquid combustion products can bequantitatively recovered by washing the inner surfaces.Theremust be no gas leakage during the test.The bomb must becapable of withstanding a hydrostatic-pressure test to approxi-mately 20 MPa at room temperature without stressing any partbeyond its elastic limit.6.2 Water BathA container large enough to hold thecombustion bomb and enough cooling water to dissipate theheat generated during the combustion process.The containershall be designed to allow a constant flow of water around thecombustion bomb.6.3 Combustion CruciblesSamples shall be burned in anopen crucible of platinum,quartz,or acceptable base-metalalloy.6.4 Firing Wire,100-mm,nickel-chromium alloy,No.34B&S gage,or platinum,No.34 or No.38B&S gage.6.5 Firing CircuitA 6 to 16-V alternating or direct currentis required for ignition purposes with an ammeter or pilot lightin the circuit to indicate when current is flowing.A step-downtransformer connected to an alternating-current lighting circuitor batteries can be used.(WarningThe ignition circuitswitch shall be of the momentary double-contact type,nor-mally open,except when held closed by the operator.Theswitch should be depressed only long enough to fire thecharge.)6.6 Balance,analytical,with a sensitivity of 0.1 mg.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 Jan.1,2013.Published January 2013.Originallyapproved in 1982.Last previous edition approved in 2007 as D4208 02(2007).DOI:10.1520/D4208-13.2For 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.*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 States1 6.7 Specific-Ion MeterA pH meter with an expandablemillivolt scale,specific-ion meter,sensitive to 0.1 mV,suitablefor method of standard addition determinations.36.8 Electrodes,chloride-sensing,with the appropriatereference-type electrode as recommended by the manufacturer.7.Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused,provided it is firs