简介:MoltensaltsynthesisofMgAl2O4powderfromindustrialaluminaandlightcalcinedMgOinKCl,LiCl,andKCl-LiClmedia,andtheinfluenceofKFat500-1000℃wereinvestigated.SynthesizedpowderswerecharacterizedbymeansofXRD,laserparticleanalyzer,andSEM,andthesynthesismechanismofMgAl2O4wasdiscussedaswell.Theresultsshowthat(1)themoltensaltcomposite(KCl-LiCl)ismorefavorableforthesynthesisofMgAl2O4thansinglemoltensalt(LiClorKCl),andLiClismorefavorablethanKCl;(2)KFcanacceleratetheformationofMgAl2O4anddecreaseitsformingtemperature;(3)synthesisofMgAl2O4powderinthemoltensaltswithoutKFiscontrolledby'template-growth'mechanism,butinthemoltensaltswithKF,itiscontrolledby'template-growth'and'dissolution-precipitation'mechanism.
简介:Cr2O3canbesinteredwellat1500℃incarbon-embeddedconditionorH2atmosphere.Butthehighchromebearingrefractoriescannotreachdensificationwhensinteredat1700℃for10hinweakreducingatmosphereformedbythecombustionoffuel,anditsapparentporosityisabout18%.Thehighchromebearingrefractoriesaremainlyusedincoalgasifiers.Thetemperatureinthefurnaceisabout1500℃andtheproductsareH2andCO,whicharejustthesinteringconditionsofthedensechromerefractorieswithapparentporositylessthan10%.Thehighchromebearingrefractoriesusedincoalgasifiersmaybesinteredagainandthenshrink,destroyingthegasifierlining.Thethermodynamiccalculationshowsthatitissafeaboutthehighchromebearingrefractoriesusedingasifiers.Itisalsoexplainedthatthehighchromebearingrefractoriescan’tbesintereddenselyinweakreducingatmosphereformedbythecombustionoffuel.Thenewsinteringtechnologiescanbeusedtoimprovethebulkdensityofthehighchromebearingrefractories.
简介:Inthisstudy,inordertoevaluatetheperformanceofhomogenizedbauxite,twoAl_2O_3-SiC-Ccastableswerepreparedusinghomogenizedbauxiteandbrownfusedcorundumasaggregates,respectively.5mass%andalusitewasintroducedintothetwocastablessoastoresearchtheeffectandmechanismofandalusiteinAl_2O_3-SiC-Ccastables.Theresultsshowedthat:(1)comparedwiththebrownfusedcorundumbasedcastables,thehomogenizedbauxitebasedcastableshadhighercoldstrengthafterheattreatment,butlowerhotmodulusofrupture;(2)additionof5mass%andalusitecouldenhancethecoldandhotmodulusofrupture,improvethethermalshockresistance,andoptimizethemicrostructureofspecimens;(3)themullitizationofandalusitewasnotobviousinthecastablesfiredat1100-1400℃.
简介:ThispapertestifiesthataluminiumandsiliconaswellastheircarbidexandnitridescanreactwithCOincarbon-containingzonetoformAl2O3andSiOgasthroughexperimentandthermodyanmicanalysis,ThegasesdiffusetooxidizedzoneandreactwithoxidizerssuchasCO2,Asaresult,Al2O3andSiO2aredepositedfromthegases,wihichblockthepores,thusreducetheamountofgasdiffusionandincreaseoxidationresistnaceofcarbon-containingmaterials.
简介:研究了纳米SiO2和β成核剂对PP/POE复合材料力学性能的影响,并用广角X射线衍射仪(WAXD)对其进行了表征。结果表明:纳米SiO2的加料方式影响PP/POE复合材料的力学性能,先将PP和纳米SiO2共混挤出,再与POE共混制备得到的复合材料冲击强度最高。当纳米SiO2含量为4%时,PP/POE/纳米SiO2复合材料的综合力学性能最好。在PP/POE/纳米SiO2复合体系中的加入β成核剂后,复合材料的拉伸强度和弯曲强度下降,而韧性进一步提高,当β成核剂含量为0.4%时,复合材料的缺口冲击强度和断裂伸长率达到最大值,拉伸强度也明显提高。XRD表明,β成核剂在纳米SiO2改性PP/POE复合体系中能显著诱导β晶的生成。
简介:SiliconoxynitridewasaddedinshapedAl2O3-SiC-Crefractorymaterialtoimprovetheslagresistanceinthispaper.Optimumaddingquantityofsiliconoxynitridepowderwasalsostudied.TheresultsshowthattheslagresistanceofAl2O3-SiC-Cshapedrefractoryisimprovedwhen2%or3%Si2N2Oisadded.AreasonableamountofSi2N2OaddedintoAl2O3-SiC-Cshapedrefractorycanproducesiliconoxideintotheslag,whichcanimprovetheviscosityofslagandpreventtheslagerosionandpenetration.
简介:Thecorrosionofrefractoriesresultsfromreactivetransport,namely,transportofagentsandchemicalreactionsoftheseagentswithimpregnatedmedium.Ononehand,thetransportinvolveseitherdiffusionorimpregnationdependingonthestateofthecorrosiveagentsandthemicrostructureofthehostmedia.Ontheotherhand,chemicalreactionsmaybeverynumerousandcomplex.ThisstudyfocusedonthereactiveimpregnationofAl2O3-CaOslagintoporoushighaluminarefractory.Thetransportpropertiesoftherefractorymaterialwereidentifiedbymeansofadedicatedcapillaryrisingtest.ChemicalreactionsbetweenthesolidhighaluminaskeletonandAl2O3-CaOslaginvolvesuccessivedissolution/precipitationmechanismsformingaluminatesoflime.Contrarytothethermodynamicpropertiesofthebinarysystem,thekineticsofthesesolid/liquidreactionsisnotwellknown.Corrosiontestsassociatedwiththequenchingmethod,XRDanalyseswereperformedforabetterunderstandingofthekinetics.Theresultsofthisstudyopenupacouplingapproachforpredictingthecorrosionwearofrefractory.
简介:本文是对日本“触媒化成”的NC-1000型催化剂和AKZO的FPC-2LD型催化剂及两者掺混的催化剂性能在小试流化床装置上进行考评.找出最佳工艺条件,为生产装置上采用掺混催化剂提供科学依据。