1、INTERNATIONA1.STANDARDISO4491-1editionSecond2023-03Meta1.1.icpowdersDeterminationofoxygencontentbyreductionmethods一f飘篁a1.guide1.inesPoudresmeta1.1.iquesDosagedeVoxygeneparIesmethodesdereduction-Panie1:Directivesgenera1.esReferencenumberIS0449b1.:2023(E)ISO2023COPYRIGHTPROTECTEDDOCUMENTISO2023IUirhM*
2、hedbdi1.iUedotherwiseupdhi.or啪UIBndttaeDmkfifiHipB1.andonnet8CH-1214Vernier,GenevaPhone：M1.22749O1.11觥ftte:丽丽BQrgPub1.ishedinSwitzer1.andContentsForewordivIntroductionv2 Scope13 Normativereferences14 Termsanddefinitions15 Samp1.ing1Meaningoftheresu1.tsaccordingtothemethodused25.1 Hydrogenasareducing
3、agent26 5.2Carbonasareducingagent:reductionextractionmethod37 Summaryoftheimp1.ementationofmethodsforoxygendeterminationbyreduction3Practica1.app1.icationofthestandardmethods4ForewordISO(theInternationa1.OrganizationforStandardization)isawor1.dwidefederationofnationa1.standardsttiugh(ISOtnnhnfaaib11
4、dghucekWwptagbody1.nmcrraMbtandriJteG4(nowhhUyca11tietrit8idano)tained.thesemethodsandgivesThetestmethodsareapp1.icab1.egenera1.1.ytoa1.1.powdersofmeta1.s,a1.1.oys,carhidesandmixturesHowever,thereexistcertain1.imitationswhichdependuponthenatureoftheana1.ysedmeta1.These21.i,WWitive停超前(S(三e4.2Wst四，的Uw
5、用白以S9his11H闻ent.Mf%傕才nrefrf1.*yhrhSPdii)辑aiiriartdragcnrffthtubttsCFhmpforc,Thetestportionsha1.1.betakenimmediate1.ypriortotheana1.ysis.5 Meaningoftheresu1.tsaccordingtothemethodused5.1 Hydrogenasareducingagent5.1.1tthetesttemperaturesprescribedinthedetermination,on1.ythefo1.1.owingmeta1.shaveoxides
6、tota1.1.yreducib1.ebyhydrogen：Fe,Ni,Co,Cu,g,Sn,Pb,W,Mo,ReA1.1.othercommonoxidesarenotreducib1.e,inparticu1.arA2O3,S1.2,ZrO2andotheroxidesofa1.ka1.i,R(Bf1.1.VHPMdBMb.rare-earthmeta1.s.Oxidesofchromium,manganese,titanium,andvanadiummay5.1.2However,otherreactionswithconstituentsofthepowdertakep1.acedur
7、ingthereductionprocess.a) WtupriwuroodJiMnniteyrtncfcrirtdjinhesentpoUiHesarnpWeaBidii*-sgam*EtaRrfcmektqkiHbmdimfe.2pure1.yconventiona1.,anditsreproducibi1.ityrequiresascrupu1.ousrespectoftheoperatingprocedure.Thismethodiscommon1.yusedinroutinecontro1.ofpowdersofcertaindefinedmeta1.sinaccordancewit
8、hISO4491-2.5.1.4Themethodofdeterminationoxygenemanatingfromhydrogen-reducib1.eoxidesinaccordancewithISO4491-3,thequantityofwater(brinedbyhydrogenreductionoftheseoxidesismeasuredbytitration.Incomparisonwiththe1.ossinhydrogenmethod,thismethodismorespecificforthefo1.1.owingreasons:Theinterferenceofmois
9、tureandadsorbedgasesispreventedbypre-treatmentat1.owtemperature.Withas1.ightmodificationoftheprocedure,itispossib1.etodeterminethewatercontentofthesamp1.e.Theinterferenceofmeta1.1.oidsandofvo1.ati1.emeta1.sisavoided.producingCarbonbemonoxideTherefore,Whicha1.ternativemeasuredareSpecifiediitration.Co
10、nsequent1.y,acarboninterference.Thisexamp1.eisapp1.icab1.emasspacticewhen0,02samp1.edpow(ierpresentistoan-interference.Oxygenmethodcorrespondinghydrogen-reducib1.ereductionofSomcaccountcarbonhydrogen-reducib1.eoxides,irrespectiveofwhethertheactua1.reductionhastakenp1.acebymeansagreementandinterpreta
11、tionhydrogen.resu1.tsuchshou1.dcase,madeWithconditionssha1.1.besubjecttoaspecia1.5.2 Carbonasareducingagent:reductionextractionmethodargon).tempcrature,onOOO0CmetaIana1.ysed,eitherOpcratingvacuumconditions11owchoseninertgasa1.1.(forexamp1.e6 Summaryoftheimp1.ementationofmethodsforoxygendetermination
12、byreductiona) carbon,forexamp1.e:whicharereducib1.ebyhydrogen(Hreducib1.e)andwhichpossib1.ycontainrepresentedbymcta1.ana1.ytica1.resu1.tshydrogen,thebehaviouroftheoxygenandcarboncontentisTab1.e1Representationofana1.ytica1.resu1.tswhenmeta1.sofoxidesarereducedbyhydrogenContentofoxygencontainedincarbo
13、nreducedoxidesOb) Anymeta1.(containingcarbonornot)However,interferenceofcarbonpresentinthesamp1.emayhavetobetakenintoaccountSomepartofthemeta1.oxides,whichotherwisemayhavebeenreducedbyhydrogen,arereducedbycarbon,1.owerresu1.twi1.1.obtained,dioxide,twonotmethodsbywaterMethod1:Oxygencontentcorrespondi
14、ngtohydrogenrcducib1.coxides,withouttakingintoaccounta1.mostofcarbon(formethodhavinginfractionCgen-reducib!emeta1.s;ontheinterna1.effectofcarbon,whenpresent,onthereductionofoxides.AnrR他物th硼蚓跌M%y冲y1.ossOm册蝌娜琼dtKy三JgWducibftgenptf1.ti8yway,thecontentofoxygennotreducedbyhydrogen(andbyinterna1.carbon)un
15、dertheconditionsofhydrogenreductioncanbedetermined.Tab1.e2ContentdetermineddependingonmethodusedPowderMethodHydrogen1.ossHydrogen-reducib1.eoxygenRcduction-CxtractionDirectmethodWithcorrectionforcarbonOninitia1.samp1.eOnsamp1.ereducedbyhydrogenNOTEInthistabic,interferencebymoisture,adsorbedgases,vo1.ati1.eandreoxidizab1.cmeta1.s,isassumedtobeabsent.ICS77.160
