简介:OnthebaseofMgO-CaOcoatingmaterialTD-CA12fortundish,anewTD-CA32withhighCaOcontentwasdeveloped,ItsCaOcontentis30%-36%andMgOcontentis45%-55%,TheapplicationresultinBaosteelshowsthatTD-CA32notonlyhasthesamepropertiesasTD-CA12butalaohastheimprovedpropertiesofdisintegrationandsteelpurifing.
简介:Thedevelopmentstatus,productiontechnologyandcharacteristicsofMgO-CaOrefractoriesareintroduced,coveringMgO-CaOclinkers,firedMgO-CaObricksandunburnedMgO-CaO-Cbricks.TheapplicationsofMgO-CaOrefractoriesinsecondaryrefiningfurnacesincludingAOD,VOD,LF-VDandGORareintroduced.
简介:DuringthereactionbetweencalciumsorbentsandSO2,calciumsorbentsarefirstcalcinedandconvertedintoCaO.CaOcanbeobtainedbycalciningCa(OH)2orCaCO3.Theporosityofthesorbentisincreasedbecauseofcalcinationandisdecreasedbecauseofsulfurization.InthecalcinationprocessH2OorCO2isescapedfromtheparticlesandporesareformedinparticles.ThereactionorconvertrateofCaOisinfluencedstronglybytheporestructurecharacters.FromCa(OH)2toCaOtheescapevelocityofH2Ooritsmasstransferisoneofthekeyfactorsinfluencingtheporeforming.Duringcalcinationprocessdifferentheatingvelocity,differentheatingtimeandtemperatureweresuggested.Thetemperaturerisingrateandcalciningtemperatureplayimportantroletotheporestructure.TheconvertratesofCaOobtainedthroughdifferentcalciningconditionswereinvestigatedexperimentally.SomeinterestingresultswereshowedthatthecalciumutilizationofCaOparticlesisdeterminednotonlybythespecialsurfaceareaandtotalporevolume,butalsobypore-sizedistribution.Themainfactorinfluencingthesulfationistheporediameterdistributionatlowersulfationtemperature.Forhigherreactiontemperaturespecificvolumeistheimportantreason.Butpore-sizedistributionisstronglyinfluencedbyheatfluxandtemperatureinthecalciningprocess.
简介:InBaotourareearthtailingsore,thegradeofrareearthisclosetothatoftheraworenearly.Therareearthsarediscardedintailingsdamcausedbyaseriouswasteofresources.Firstofall,thedecompositionproductsofbastnaesite-andmonazite-mixedrareearthtailingsinCaOinreducingatmospherewerestudiedbymeansofX-raydiffraction(XRD).TheresultsshowthatthenormalproductsareCeO_2,Ce_2O_3,Ca_5F(PO_4)_3,andCe_(0.75)Nd_(0.25)O_(1.875),andtherearenoREPO_4andREFCO_3.Secondly,theroastedproductwasextractedinHCl,andtherelationshipamongroastingtime,roastingtemperature,CaOaddition,andextractiontemperaturewasstudiedbythequadraticregression-orthogonalanalysis.Throughanalysis,theoptimumprocessconditionsofmixedrareearthtailingsextractedareobtainedasfollows:roastingtimeof60min,roastingtemperatureof800℃,CaOadditionof30%,extractiontemperatureof80℃,andextractionratioof99.18%.
简介:BycarbothermalreductionofMgOwithblackcarbonasreductionagentatahightemperature,MgOwasdepositedonthesurfaceofMgO-CaOclinker(ascoating)toimprovetheclinker'shydrationresistance.Inthepaper,effectofdepositiontemperatureandholdingtimeonthehydrationresistanceofthetreatedMgO-CaO,thedepositionmechanismandMgOcoatingkineticswereinvestigatedwithhydrationresistancetest,X-raydiffractometry(XRD)andscanningelectronicmicroscope(SEM).ResultsshowedMgOcoatinggrewina2DmodeonthesurfaceofMgO-CaOparticles;theMgOcoatingimprovedthehydrationresistanceofthecoatedMgO-CaOclinker,andthecoatedclinkerwouldbecomestrongerwhencoatedathigherdepositiontemperatureandlongerholdingtime.ThemeasurementsalsofoundthatMgOdepositionprocessvariedwiththedepositiontemperature:itwasmainlyachemical-controlledprocessattemperaturesbetween1400-1500℃,withanapparentactivationenergy(AAE)of97.8kJ·mol~(-1);itwouldchangeintoadiffusion-controlledprocesswhenthetemperaturerisingto1500-1600℃,withapparentactivationenergyof19.2kJ·mol~(-1).
简介:Coprecipitationsupercriticalfluiddryingtechnologyhasbeenemployedtosynthesizecalcia-stabilizedzirconiaultrafinepowderwithlow-costinorganicsaltsasthestartingmaterials.Thesinteringbehaviorsofthesepowderswerealsoinvestigated.Theresultsshowedthatsupercriticalfluiddryingcouldeffectivelyalleviatethehardagglomerationofgrainsduringthegeldryingprocess,andthemorphologyofthepowderretainedthenetworktextureoftheoriginalgel.Theresultingparticleswerecharacterizedbysmallparticlesize(5~20nm),bettermonodispersityandhighsurfacearea,whichgaverisetohighactivityandsinterability.Consequently,thesepowderscouldreadilybecompactedintothedesiredshapeandtheirdensificationcouldbecarriedoutinshortertimeandatlowertemperatures.Forinstance,nanometer-sizedpowdercalcinedat600℃for2hcouldbecold-pressedintoagreenbodyandsinteredat1100°for0.5htoattainadensebodywithbulkdensityof5.9718g/cm3andspecificporevolumeof0.0008cm3/g.
简介:Inthis,phasecompsitionandthermalexpansionbehaviourofCaOStabilisedrefractorieswerestudied,Specialattentionwaspaidtotheexpasionbehaviourofthreematerialswithdifferentphasecomposition,TheresearchresultsindicatedthattheexpansionbehaviourcouldbeimprovedbymodifyingthestabilizationofZrO2,whichthusleadstotheincreaseinthethermalshockresistanceandpossiblyeroionresistaceofas-obtainedCaOstabilisedZrOmaterial.
简介:摘要:随着人们生活水平的提高,随之也带来了一系列的环保问题,其中垃圾处理成为国内外关注的焦点问题,而目前国内垃圾处理方式,以填埋为主,占用大量土地的填埋处理方式占比高达70%,随着城市及其周边用地的紧张,大力发展垃圾焚烧产业势在必行。而在垃圾焚烧中,会产生二噁英等一些有害气体,在传统的垃圾焚烧炉里,很难处理垃圾焚烧产生的二噁英等有毒气体,以致排出废气的二噁英含量严重超标,严重危害人们的身体健康。本文提出了一种在原有的CAO垃圾焚烧炉的基础上进行改进的装置,能够最大程度上减少垃圾焚烧尾气中的二噁英等有毒气体的排出,从而促进垃圾焚烧行业的发展。
简介:Thecorrosionofrefractoriesresultsfromreactivetransport,namely,transportofagentsandchemicalreactionsoftheseagentswithimpregnatedmedium.Ononehand,thetransportinvolveseitherdiffusionorimpregnationdependingonthestateofthecorrosiveagentsandthemicrostructureofthehostmedia.Ontheotherhand,chemicalreactionsmaybeverynumerousandcomplex.ThisstudyfocusedonthereactiveimpregnationofAl2O3-CaOslagintoporoushighaluminarefractory.Thetransportpropertiesoftherefractorymaterialwereidentifiedbymeansofadedicatedcapillaryrisingtest.ChemicalreactionsbetweenthesolidhighaluminaskeletonandAl2O3-CaOslaginvolvesuccessivedissolution/precipitationmechanismsformingaluminatesoflime.Contrarytothethermodynamicpropertiesofthebinarysystem,thekineticsofthesesolid/liquidreactionsisnotwellknown.Corrosiontestsassociatedwiththequenchingmethod,XRDanalyseswereperformedforabetterunderstandingofthekinetics.Theresultsofthisstudyopenupacouplingapproachforpredictingthecorrosionwearofrefractory.