简介:Theadsorptionbehaviorsandmechanismofanovelchelateresin,macroporousphosphonicacidresin(PAR)forGd(Ⅲ)wereinvestigated.Thestaticallyanddynamicallysaturatedadsorptioncapacityisrespectively308mg·g-1resinand296mg·g-1resinat298KinHac-NaAcmediumatpH5.6.Gd(Ⅲ)adsorbedonPARcanbereductivelyelutedby0.5~5.0mol·L-1HClusedaseluantandtheelutionpercentageisupto94.7%in1.0mol·L-1HCl.Theresincanberegeneratedandreusedwithoutapparentdecreaseinadsorptioncapacity.Theapparentadsorptionrateconstantisk298=3.96×10-5s-1.TheadsorptionbehaviorofPARforGd(Ⅲ)conformstotheFreundlichisotherm.Thethermodynamicadsorptionparameter,enthalpychange△HofPARforGd(Ⅲ)is22.6kJ·mol-1.Theapparentadsorptionactivationenergy(Ea)ofPARforGd(Ⅲ)is5.0kJ·mol-1.ThemolarcoordinationratioofthefunctionalgroupofPARtoGd(Ⅲ)isabout3∶1.TheadsorptionmechanismofPARforGd(Ⅲ)wasexaminedbyusingchemicalmethodandIRspectrometry.
简介:ThegrainrefiningmechanismofC-Mnsteelsheetoncompactstripproduction(CSP)linewasinvestigatedinthisstudy.Thegrainwasabout100μmafterF1passanddecreasedallthewayoftherollingprocess(F2-F6)to15μm.Repeatedphasetransformationexperimentwasconductedtothesteelforgrainrefinement.Thephasetransformationat860℃and920℃canrefinethegrainsizeto7.5μm.
简介:AtBaoshanIron&SteelCo.,Ltd.,cornercracksofboroncontainingLCAKsteelslabshadcausedremarkablequalitylossandmassflowdisorder.Withthehelpoffractographyandthermodynamicsanalysis,theembrittlementmechanismofthissteelgradewasstudiedandtheresultsareasfollows:①Thetransformationfromγtoαstartsattheaustenitegrainboundariesandalayerofthinferritefilmgraduallyformsaroundtheaustenitegrains.Strainconcentrationwillpreferentiallystartinsidetheferritephasewhenthestressaccumulatestoacertainlevel.②ThecoarseBNparticlesacceleratedlyprecipitatedattheγ/αinterfacesfurtherdeterioratetheductilityoftheferritefilm,andbrittlenessresultsinstrainconcentrationandmicrovoidcoalescenceinsidetheferritefilm.Thereforetheaustenitegrainboundariesarepronetointergranularfailure.③ThestoichiometryamongAl,NandBisaveryimportantfactorinfluencingthehotductilityofthissteelgrade.BycontrolingtheB-to-Natomicratiotoabove1,allNcanbefixedbyBinsteadofAl.Thuscoarse-grainedsteelisavailableandfewergrainboundariesandhigherductilitycanreducetheriskofcornercracks.④ByadjustingtheB-to-Natomicratio,BaoshanIron&SteelCo.,Ltd.successfullyreducedthenumberofcrackstonearlyonetenthofthatinthepastandthehottensiletestsconfirmedremarkableimprovementinthehotductilityofthissteel.
简介:Theformationofsolidsolutioncombinedwithtricalciumphosphateanddicalciumsilicatecouldpromoteaconsiderableremovalofphosphorusfromliquidslagtosolidduringhotmetaldephosphorization,andthusthedephosphorizationbyusingmultiphasefluxescouldsignificantlydecreasetheconsumptionoflime.However,thereactionmechanismofmultiphasefluxeshasnotbeenunderstoodclearly.Inthepresentstudy,thephasediagramfortheCaO-SiO2-FeO-P2O5systemhasbeenmeasuredwithcertainoxygenpartialpressureathotmetalpretreatmenttemperature.ComparingwiththeCaO-SiO2-FeOsystem,shrinkageofliquidphaseareaathigherFeOcontentswasobservedat1673Kwithoxygenpartialpressureof9.2×10-11atm.
简介:Reversed-phasepaperchromatographytechniqueisusedforstudyontheextractionmechanismandsep-arationofrareearthelements.Asthestationaryphase,chromatographicpaperstripsareimpregnatedwithasolutionofmonomyristylphosphoricacid(MPA)inchloroform.Mineralacidsareusedasdevelopers.Theeffectofconcentrationofacidsand/orsaltsuponRfhasbeeninvestigated.Accordingtothere-sultsofRfvaluesforagivenrareearthelementinvariousacids,theorderofextractionabilityisHCl>HNO3>H2SO4.Atetradeffectisclearlyobserved.fortheRfvalueofrareearthelements.TheeffectsofotherparametersontheRfvalue,suchasthequantitiesofextractantretainedbythepaperandthetemperaturearealsoexamined.BasedonthedeterminationofthemolarratioofMPAtorareearthelementsandthenumberofH+ionsreleasedinextractionreaction,areasonablemechanismisproposed.Themutualseparationofheavyrareearthelementswillbebetterthanthatofthelightrareearthgroupbecauseofthelargerseparationcoefficientoftheformer.AmixtureofHo-Er-Tm-Luissuccessfullyseparatedbythepresentmethod.
简介:TheextractionofCe(Ⅳ)inH2SO4/H3PO4systemwasinvestigatedsystematicallyusingbifunctionalionicliquidextractants(Bif-ILES)[A336][P507],[A336][P204]and[A336][C272]inn-heptane.TheeffectsofH2SO4concentration,extractantconcentrationandsalting-outagentconcentrationwereobservedindetail.TheextractionmechanismofCe(Ⅳ)inH2SO4/H3PO4systemwasobtained.ThecomparisonwithotherextractantssuchasCyanex923,TBPwasalsostudied.Thermodynamicfunctionsoftheextractionreactionwerecalculated,showingthattheextractionwasanexothermicprocess.TheseparationofCe(Ⅳ)fromRE(Ⅲ)andTh(Ⅳ)wasalsoinvestigated.TheresultindicatedthatCe(Ⅳ)couldbeselectivelyextractedinthissystem.CePO4nanoparticleswereobtainedintheprocessofstrippingusingH2O2inH2SO4/H3PO4system.X-raydiffraction(XRD),scanningelectronmicroscopy(SEM)andspectroscopywereadoptedforthecharacterizationofthesample.
简介:Whitelight-emittingYVO_4:1mol.%Dy~(3+),xmol.%Eu~(3+)phosphorpowderswithordermorphologyandwellcrystallizationwerehydrothermallysynthesizedat180°C.Themicrostructure,white-lightemission,andlight-emittingmechanismofthepowderswerecarefullystudiedusingX-raydiffractometry,scanningelectronmicroscopyandphotoluminescencespectra.TheexcitationandemissionspectraofthephosphorpowdersindicatedthecoexistenceofefficientenergytransferfromEu~(3+)toDy~(3+)andinefficientenergytransferfromDy~(3+)toEu~(3+)besidestheenergytransferfromVO_4~(3–)toEu~(3+).IncreasingtheEu~(~(3+))concentrationinitiallyenhancedandthenweakenedtheluminescentintensityofDy~(3+).Thewhite-lightemissionsofYVO_4:1mol.%Dy~(3+),xmol.%Eu~(3+)phosphorpowderswerebothrelatedtotheenergytransferbetweenVO_4~(3–)andDy~(3+)/Eu~(3+),aswellasbetweenEu~(3+)andDy~(3+).TheinefficientenergytransferfromDy~(3+)toEu~(3+)wasfirstfound.