84-paper-structural change of the iron ore sintering bed and

1、聯(lián)系人：李咸偉聯(lián)系人：李咸偉26643990StructuralChangeoftheIroneSinteringBeditsControlEikiKASAI(InstituteofMultidisciplinaryResearchfAdvancedMaterialsTohokuUniversity211KatahiraSendai9813108Japan)Abstract:Designofbedstructureisapromisin

2、gapproachtoincreasetheproductivityofsinterundertheconditionofincreasinguseofironescontaininghighcombinedwater.InthispapertheacteristicsofthestructuralchangeofthesinteringbedobtainedbytheinsituobservationusingXrayCTSisdes

3、cribedbasedonitanewprocessimage“MEBIOS”isillustrated.Furtheraseriesofmodelexperimentswereconductedtheresultsprovedthatthisprocessprovideamechanismofhighspeedsintering.Keywd:IronesinteringDesignofbedstructuresintercakevoi

4、dwklargepelletXrayCTSIntroductionIntheironesinteringprocessthestructuralchangeofsinteringbedisasignificantkeytoimprovecontroltheproductionrateyieldstrengthofsinterproduct.Thestructuralchangeofthebedcanberegardedasthedras

5、ticchangefromapackedbedstructureoftherawmaterialgranulestoasintercakeconsistedofasolidcontinuumlargervoidwkssmallpes.Suchchangemaystartwiththemeltfmationatthepartswherefineironelimestoneareexistedtheamountofmeltincreases

6、withincreaseinbedtemperature.Thefmedmeltbridgessolidparticlestofmclustersfinallythestructureofsintercake(seeFigure1).Thevoidstructureofthesinteringbedgovernsbedpermeabilityinhightemperatureinfluencesyieldstrengthofthesin

7、ter.Therefeitsacterizationhavebeenattemptedbydifferentways1)2).Howeverquantitativeinfmationwasrestrictedbecauseoftheirextremecomplexity.Inthisreptsomeimptantresultsobtainedthroughthedirectinsituobservationofthechangeinth

8、ebedstructureduringsinteringbyusinganXrayComputerizedTomographyScanner(CTS)aredescribed.FurtheranewconceptofthesinteringprocessnamelyMEBIOS(MosaicEmBeddedIroneSintering)Processisproposedwhichaimstoenlargetheprocessflexib

9、ilityofrawmaterialstoimproveproductivity.2.Insituobservationofthestructuralchangeofsinteringbed2.1Experimentalapparatusprocedure3(b)respectively.Theareaboundedbywhiterectangleindicatestheinitiallocationofsegregatedparts.

10、Inthecasesof3.0mass%cokesomeunsinteredpartsareobservedespeciallyintheupperperipheralpartsofthebeds.Intheallcaseshoweverlargevoidsfmedaroundthesegregationpartsindependentofthecokemixingratio.Itcanbepointedoutthatthevoidsd

11、evelopdownwardinthecasesofthecokesegregationthealuminafibersheetwhileitfmsatthepartofsegregationinthecaseofCaOsegregation.Asfthecokesegregationexcessheatsupplyduetocokecombustioncausesconsiderablemeltingofthegranulesloca

12、tedunderthesegregatedpartthefmedmeltseemstoperatedownward.TheliquidustemperatureoftheCaO20mass%Fe2O3(1205oC)issignificantlylowerthanthatoftheadheringlayerofsurroundinggranules(CaO10mass%Fe2O3:methan1400oC)3).Therefememel

13、tfmsatthesegregatedpartincontrastwiththecaseofthecokesegregationthefmedmeltseemstoperateinalldirections.Asfaluminasheetalthoughthevoidfmationisnotassignificantasthecaseofthecokesegregationmeltstartstofmatthevicinityofthe

14、bottomsurfaceofthesheetthevoidsuccessivelydevelopsdownwardasifsomeexcessheatissuppliedtothatpart.Theoverlap(superimposing)ofapairofsucceedingimagescanvisualizetheplaceswherethesignificantstructuralchangeofbedproceeds.The

15、separtsusuallyfmazonewithacertainthicknessintheverticaldirection.Anapparentstructuralchangefrontinthebedcanberepresentedbydrawingalineofcontourcrespondingtothelocationofthezone.Figure4Figure3.Structuralchangeofthecrossse

16、ctionobtainedbythesegregatedsinteringpotexperiment.20mm6minFinal7min8minCokesegregationAluminafibersheetCaOsegregation(a)Coke:3.0mass%CokesegregationAluminafibersheetCaOsegregation(b)Coke:3.5mass%Figure4.Structuralfrontm