Designation:D3872−05(Reapproved2011)StandardTestMethodforFerrousIroninIronOxides1ThisstandardisissuedunderthefixeddesignationD3872;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthequantitativedeterminationofferrousoxide(FeO)byoxidationofferrousiron(Fe++)inanacidsolutiontotheferricstate(Fe+++)andtitrationwithpotassiumdichromateusingdiphenylamineastheindicator.1.2Thistestmethodisapplicabletosyntheticblackironoxide,naturalblackironoxide,magnetiteorbrownironoxidewherepartoftheironcontentispresentintheferrousstate(Note1).Itisapplicabletoironoxideswheretheferrousironcontentrangesfrom50to0.20%.NOTE1—NaturalironoxidesandmagnetitemaycontaintracesofmetallicironthatwillbecombinedwithandanalyzedasFeO.1.3Thisstandarddoesnotpurporttoaddressthesafetyconcernsifany,problemsassociatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D50TestMethodsforChemicalAnalysisofYellow,Orange,Red,andBrownPigmentsContainingIronandManga-neseD280TestMethodsforHygroscopicMoisture(andOtherMatterVolatileUndertheTestConditions)inPigmentsD769SpecificationforBlackSyntheticIronOxideD1193SpecificationforReagentWaterD3722SpecificationforNaturalRedandBrownIronOxidePigmentsD3724SpecificationforSyntheticBrownIronOxidePig-ment3.SignificanceandUse3.1Thistestmethodmaybeusedforproductionqualitycontrolorspecificationacceptance.4.Apparatus4.1Thedigestionapparatusconsistsofastandard500-mLErlenmeyerflaskfittedwithatwo-holerubberstopperandglasstubing,asshowninFig.1,toprovidefortheintroductionoftheinertgasandventforgasanddigestionfumes.5.Reagents5.1PurityofReagents—Reagentgradechemicalsshallbeusedinalltests.Unlessotherwiseindi...
