简介：Bariumsulfateaggregateswithanaveragesizeof0.5μmweresynthesizedatpH7,directedbyethylenediaminetetraaceticacid（EDTA）anions.Theparticlemorphology,chemicalcomposition,andsizedistributionoftheBaSO4aggregateswerecharacterized.Theas-synthesizedBaSO4particlesweresphericalandcomprisedmanyinterconnectednanoballs,ofwhichthesurfacepropertieswereaffectedbytheEDTAanions.TheadsorptionofEDTAanionsreversedthechargeandweakenedthesurfacepolarityofBaSO4,instigatingtheformationofaggregatesbyaself-assemblyandtransformationprocess.TheresultingBaSO4particlesatpH9-10wereellipsoidalandfeaturedsmoothsurfaces.BasedonthezetapotentialofBaSO4,variationsinthemorphologyinducedbychangesinpHwerecloselyrelatedtotheadsorptionofmono-andmulti-valentanionsontotheelectricaldoublelayerofBaSO4.

简介：ThepresentstudyinvestigatedtheinfluenceofhightemperatureoxidationandreductionpretreatmentsontheleachingrateofPanzhihuailmenite.Theas-pretreatedilmenitewasleachedwith20%HClat105℃.Theleachingprocesswascontrolledbythephasesandmicrostructuresthatevolvedduringthepretreatmentprocesses.Theleachingkineticsofpurehematite,ilmeniteandpseudobrookitewerecharacterizedtoclarifythephaseeffectontheiron-leachingrate;therateofironleachingoccursinthefollowingorderintheHClsolution:hematite（ferriciron）>ilmenite（ferrousiron）>>pseudobrookite（ferriciron）.Therefore,theoften-citednotionthatferrousirondissolvesfasterinHClsolutionsthanferricironwhenexplainingthepretreatmenteffectsisinaccurate.Moreover,theoxidationpretreatment（at600-1000℃for4h）cannotdestroythedensestructureofthePanzhihuailmenite.Therefore,theinfluenceexertedbytheoxidationontheleachingprocessisprimarilydeterminedbythephasechange;oxidationat600and700℃slightlyincreasedtherateofironleachingbecausetheilmenitewastransformedintohematite,whiletheoxidationat900-1000℃significantlyreducedtherateofironleachingbecauseapseudobrookitephaseformed.Thereductioneffectwassubsequentlyinvestigated;theas-oxidizedilmenitewasreducedunderH2at750℃for30min.Thereductionsignificantlyacceleratedtherateofsubsequentironleachingsuchthatnearlyalloftheironhaddissolvedafterleachingfor2hin20%HClat105℃.Thisenhancediron-leachingrateismainlyattributedtothecracksandholesthatformedduringthereductionprocess.

简介：ZrO2nanopowdersbasedstearicacidphasechangematerials(PCMs)werepreparedbyhigh-energymilling.Theconceptofheatcapacityfactor(HCF)wasusedtoanalyzethethermalpropertiesofthematerials.TheheatstoragepropertyofPCMs,containingthesamecontentofstearicacid(23%bymass)inthestartingmaterialsbutsynthesizedbydifferenttechnicalprocesses,wasinvestigatedbyusingHCF.Itwasfoundthattherewerevastinfluencesofdifferentdispersantsontheheatcapacity.Thesamplespreparedwithchloroformprovidedthebestheatstorageabilityinallsamplestested.

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