简介:Theapplicationofmicrowavetechniqueinthehydrometallurgyofnickellateriteoreswasdescribed.Themixtureofnickellateriteoresandsulfuricacidwaspre-treatedbymicrowaveirradiation.Thedissolvingofnickelwasconductedinhotwaterattheatmosphericpressure.Theeffectsoffactors,suchasmicrowavepower,microwaveirradiationtime,andsulfuricaciddosage,wereinvestigated.Inmicrowavefield,themigrationofionicspeciesand/orrotationofdipolarspeciespromotetheliquid?solidreactionprocessduetotheincreasedcontactareaofreactantsandleachingreactionrateconstant.Thankstothestrengtheningactionofmicrowave,themicrowave-assistedleachingprocesshasitsadvantages,suchashigherextractingratethanconventionalatmosphericleaching,andnoneedforhigh-pressureoperationashighpressureacidleaching(HPAL).Theferricironinleachingsolutioncouldbeeffectivelyremovedbysodiumjarositeprocesswithalittlelossofnickelinthejarositeprecipitate.
简介:Ultra-finetitaniumcarbonitride(TiCN)matrixmaterialswithagrainsizelessthan1μmweresuccessfullypreparedbyvacuummicrowavesintering.ThemillingprocessforrawTiCNparticlesandthemicrostructureandpropertiesofcermetsproducedwithacompositionof15wt.%WC-17wt.%(Co+Ni)-9wt.%Mo2C-59wt.%Ti0.7N0.3andsinteredbyvacuummicrowavewereanalyzedbyscanningelectronmicroscopy(SEM)andX-raydiffraction(XRD).Theresultsshowthataball-to-powdermassratioof8:1andamillingtimeof50hprovidedappropriateconditionsfortheproductionofultra-fineTiCNsolidsolutionpowders.Theuseofvacuummicrowavesinteringproducedcermetswithmuchfinergrainandblackcorestructuresandhigherrelativedensityandhardnessthanthoseproducedbyvacuumsinteringtechnology.
简介:Thenon-isothermalleachingkineticsofprimarytitanium-richmaterialbymicrowaveheatingwasinvestigated,andthetemperature-pressurecurvesofleachingsystemandmicrowaveabsorptioncharacteristicsofmixturesolutionsbeforeandafterleachingweremeasured.Theresearchofnon-isothermalkineticswasevaluatedbytheleachingrateofFeandthetotalapparentvelocityequationofthenon-isothermalkineticsofleachingforprimarytitanium-richmaterialbymicrowaveheatingwasobtained.Itisshownfromthetemperature-pressurecurvesthatthehightemperatureandhighpressureofclosedleachingsystemarefavorabletotheenhancementoftheleachingrateofFe.Microwaveabsorptioncharacteristicsofmixturesolutionsbeforeandafterleachingshowthatthereareabruptchangesofmicrowaveabsorptioncharacteristicsfor15%HClsolutionandthemixturesolutionafterleachingby20%HCl.
简介:La-dopedSr-hexaferrite(Sr_(1-x)La_xFe_(12)O_(19))(x=0.05,0.10,0.15,0.20)nanopowderswithparticlesizerangingfrom80to110nmweresuccessfullysynthesizedbysol-gelauto-combustion.Thephaseformationtemperatureincreases,whiletheparticlesizedecreasesastheLadopingcontentgoesup.ThepartialsubstitutionofSr~(2+)byLa~(3+)resultsinthesuppressioneffectsonthegrowth-upofthecrystallitesandtheenhancementoftheelectronhoppingbetweenFe~(3+)withdifferentvalences,whichleadstotheimprovementinthedielectriclossandmagneticloss.Therefore,boththemicrowaveabsorbingabilitiesandabsorbingfrequencyrangesaretunedbyLa-doping.ThesynthesizedSr-hexaferritenanopowderswithdopingelementcontentof0.10demonstratethefinebroadmicrowaveabsorbingproperties.