ASTM_D_3516_-_89_2011.pdf

Designation:D351689(Reapproved 2011)Standard Test Methods forAshing Cellulose1This standard is issued under the fixed designation D3516;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 These test methods cover four ashing methods forcellulose.These are intended for use on unbleached andbleached cellulose in sheeted or bulk fiber form.Each one ofthe test methods has advantages,so that preference applica-tions exist for all four.1.2 The test methods appear as follows:SectionsTest Method AAsh in Cellulose at 575C6 to 11Test Method BSulfated Ash in Cellulose at 575C12 to 17Test Method CAshing Cellulose by Schoniger Oxidation18 to 22Test Method DWet Ashing of Cellulose for Inorganics23 to 291.3 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.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.For a specifichazard statement,see 20.6.1.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1348 Test Methods for Moisture in Cellulose3.Summary of Test Methods3.1 Test Method A,Ash in Cellulose at 575CThis testmethod measures the ash content of cellulose,which is definedfor this test as the residue remaining after ignition at 575 625C until all carbon has been burned off.It is the simplest ofthe four test methods for the determination of ash content only,and it should not be considered as a standard preparativeprocedure for elemental analysis.NOTE1The ash content at this ignition temperature is a reasonablemeasure of the mineral salts and inorganic foreign matter in the cellulose.The weight of ash obtained varies with the temperature of ignition.Highertemperatures(850C)will convert calcium carbonate and other carbonatesto the oxides and thus give lower values for ash.The composition of ashmay vary with the pulping process employed for manufacture,whichlimits the significance of the ash determination in absolute terms.3.2 Test Method B,Sulfated Ash in Cellulose at 575CInthis ashing procedure the metal salts are converted to sulfatesby treatment with sulfuric acid and ignition at 575 6 25C toovercome limitations of Test Method A.It should not beconsidered as a standard preparative test method for elementalanalysis.NOTE2Conventional dry ashing at high temperature(over 850C)results in loss of carbon dioxide from metal carbonates,decomposition ofmagnesium sulfate,and loss of sodium salts.Ashing at lower temperatures(575C)gives a better estimate of the inorganic impurities,but has thedisadvantage of requiring a long ignition time and also the heat producedby the burning pulp can raise the temperature far above 575C for a shortperiod of time,converting calcium carbonate to the oxide in varyingamounts.The sulfated ash method overcomes these objectionable featuresand has additional advantages.It is relatively insensitive to ignition time.Ash weight remains constant during weighing,and because the ash doesnot melt it will not attack the crucible.3.3 Test Method C,Ashing Cellulose by SchonigerOxidationThis test method is generally applicable to ashingcellulose for subsequent analysis of inorganic constituents.Theprocedure utilizes the Schoniger technique in which the cellu-lose is burned in a combustion flask and all combustionproducts are dissolved in an aqueous medium,thus avoidingthe possibility of physical loss of sample such as can occur indry ashing(Test Methods A and B).A limitation is therelatively small sample of 1 g,which can be ashed withoutexcessively large apparatus in which to carry out the oxidationstep.Small specimens may not be adequately representativewhere a particulate contaminate is involved.3.4 Test Method D,Wet Ashing of Cellulose for InorganicsThis test method is recommended for ashing cellulose forsubsequent analysis of inorganic constituents.The procedureemploys saturation of the cellulose with a concentrated solu-tion of hydrogen peroxide followed by incremental addition toa small volume of concentrated sulfuric acid.It has the1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Subcommittee D01.36 on Cellulose and Cellulose Derivatives.Current edition approved June 1,2011.Published June 2011.Originallyapproved in 1976.Last previous edition approved in 2006 as D3516 89(2006).DOI:10.1520/D3516-89R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual