ASTM_D_2795_-_95.pdf

Designation:D 2795 95Standard Test Methods forAnalysis of Coal and Coke Ash1This standard is issued under the fixed designation D 2795;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods cover the analysis of coal and cokeash for the commonly determined major elements.1.2 The test methods appear in the following order:SectionsSilicon Dioxide(SiO2)10 to 12Aluminum Oxide(Al2O3)13 to 15Ferric Oxide(Fe2O3)16 to 18Titanium Dioxide(TiO2)19 to 22Phosphorus Pentoxide(P2O5)23 to 25Calcium Oxide(CaO),and Magnesium Oxide(MgO)26 to 29Sodium Oxide(Na2O)and Potassium Oxide(K2O)30 to 33NOTE1Test Methods D 1757 is used for determination of sulfur.1.3 The values stated in SI units(Practice E 380)shall beregarded as the standard.The values given in parentheses arefor information only.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:D 346 Practice for Collection and Preparation of CokeSamples for Laboratory Analysis2D 1193 Specification for Reagent Water3D 1757 Test Methods for Sulfur in Ash from Coal andCoke2D 2013 Test Method for Preparing Coal Samples for Analy-sis2D 3173 Test Method for Moisture in theAnalysis Sample ofCoal and Coke2D 3174 Test Method forAsh in theAnalysis Sample of Coaland Coke from Coal2D 3180 Practice for Calculating Coal and Coke Analysesfrom As-Determined to Different Bases2D 5142 Test Methods for Proximate Analysis of the Analy-sis Sample of Coal and Coke by Instrumental Procedures2E 380 Practice for Use of the International System of Units(SI)(the Modernized Metric System)43.Summary of Test Methods3.1 The coal or coke to be analyzed is ashed under standardconditions and ignited to constant weight.Two solutions areprepared from the ash.SolutionAis obtained by fusing the ashwith sodium hydroxide(NaOH)followed by a final dissolutionof the melt in dilute hydrochloric acid(HCl).Solution B isprepared by decomposition of the ash with sulfuric(H2SO4),hydrofluoric(HF),and nitric(HNO3)acids.Solution A is usedfor the analysis of SiO2and Al2O3,and Solution B for theremaining elements.3.2 The two solutions are analyzed by a combination ofmethods:(1)spectrophotometric procedures are used for SiO2,Al2O3,Fe2O3,TiO2,and P2O5;(2)chelatometric titration forCaO and MgO;and(3)flame photometry for Na2O and K2O.See Fig.1 for a general outline of the methods and proceduresused for each determination.4.Significance and Use4.1 Acompositional analysis of the ash is often useful in thetotal coal quality description.Knowledge of the ash composi-tion is also useful in predicting the behavior of the ashes andslags in combustion chambers.Utilization of the coal combus-tion ash by-products sometimes depends on the chemicalcomposition of the ash.4.2 It should be noted that chemical composition of labora-tory prepared coal ash may not exactly represent the compo-sition of mineral matter in the coal,or the composition of thefly ash and slags resulting from the commercial scale burningof the coal.5.Apparatus5.1 Balance,sensitive to 0.1 mg.5.2 CruciblesNickel crucibles of 50-cm3capacity shall beused for NaOH fusion of the ash,and platinum crucibles of30-cm3capacity shall be used for decomposition of the ashwith HF.5.3 Emission Flame Photometer.5.4 Muffle FurnaceElectrically heated muffle furnacewith good air circulation and capable of maintaining a tem-perature of approximately 750C.1These test methods are under the jurisdiction ofASTM Committee D-5 on Coaland Coke and are the direct responsibility of Subcommittee D05.29 on MajorElements in Ash and Trace Elements of Coal.Current edition approved Sept.10,1995.Published April 1996.Originallypublished as D 2795 69.Last previous edition D 2795 86(1991)e1.2Annual Book of ASTM Standards,Vol 05.05.3Annual Book of ASTM Standards,Vol 11.01.4Annual Book of ASTM Standards,Vol 14.02.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.5.5 Absorption Spectrophotometer,visible region 380 to780 nm.5.6 Sieves,150 and 250-m(No.100 and No.60)U.S.A.standard.6.Purity of Reagents and Materials6.1 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.5Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6