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BiographyLiＧliYANGMaster EＧmail８４２６１０３９７qq1049008com ReceivedDateJanuary１４２０１３CorrespondingAuthorHongＧmingWANGDoctorAssociateProfessor EＧmailwhm１９７４sina1049008cn
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JOURNALOFIRONANDSTEELRESEARCHINTERNATIONAL1049008２０１４２１(８)７４５Ｇ７４８10512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273105127310512731051273
EffectofBoronMudandCaF２onSurfaceTensionandDensityofCaOＧSiO２ＧB２O３TernarySlagSystems
LiＧliYANG１２ HongＧmingWANG１２ XiangZHU１２ GuiＧrongLI１２
(１SchoolofMaterialsScienceandEngineeringJiangsuUniversityZhenjiang２１２０１３JiangsuChina ２JiangsuProvinceKeyLaboratoryofHighＧEndStructuralMaterialsZhenjiang２１２０１３JiangsuChina)
AbstractTheeffectofboronmudandCaF２whichwereusedasfluxingagentsonsurfacetensionanddensityofCaOＧSiO２ＧB２O３ternaryslagsystemswasinvestigatedThesurfacetensionanddensityweremeasuredbyusingtheringdetachmentmethodandArchimedeanmethodrespectivelyTheresultsindicatedthatsurfacetensionanddensiＧtyoftheslagsystemsdecreasedwithincreasingtemperatureintherangeof１３８０－１４８０When５－１０ CaF２
wasemployedasfluxingagentthesurfacetensionanddensityofslagweredecreasedwithincreasingCaF２contentandthesurfacetensionchangedfrom０1049008３to０1049008６Nmwhilethedensitychangedfrom３1049008４to４1049008１gcm３Howeverwhenusing５－１０boronmudasfluxingagentthesurfacetensionwasenhancedwhereasthedensitydecreasedwiththeincreaseofboronmudcontentandthevariationrangewas０1049008４－０1049008６Nmforsurfacetensionand３1049008２－３1049008９gcm３forthedensityAsaconclusionusingboronmudasfluxingagenttosubstituteforCaF２didnotcausesignifiＧcantchangesinslagsurfacetensionanddensityKeywordsboronmudcalciumfluoridesurfacetensiondensityDOI１０1049008１３２２８j1049008boyuan1049008issn１００６Ｇ７０６x1049008２０１３００１９
Thedevelopmentdirectionofsteelmakingishighefficiencyhighcleanlinessandeconomy[１]Fluorineiswidelyemployedasfluxingagentinmetallurgicalfluxwhichcanimprovetherefiningefficiencybyacceleratingthedecompositionoflimeand makingthefluidityoftheslagbetterHoweverthereareseriousshortcomingsathightemperaturewhenusingfluorine[２]ForexamplefluorinecancorroderefracＧtorymaterialswhichwillreducefurnacelifeMoreＧoverbecauseofitspoorstabilityathightemperaＧtureitcanreactwiththeacidoxidesinslagtoformseriousfluorinepollutionwhichwilldomuchharmtoenvironmentRecentlyasmoreandmorepeopleattachimportancetoenvironmentalprotectiontheutilizationoffluorinehasbeenlimitedwhichwillinevitablyleadtotheincreaseinthecostofusingfluorineAtthesametimealargeamountofboronmudwhosemaincomponentsareMgOCaOFe２O３andB２O３hasbeengeneratedafterproducingborax
SinceFe２O３andB２O３ havegreatfluxingeffectonCaOＧbasedsteelmakingslagsystemsespeciallyithasbeenprovedthatthefluxingactionofB２O３isbetterthanthatofCaF２theresearchershavepaidmoreand moreattentionstousingboron mudinＧsteadofCaF２asthefluxingagent[３－５]InthispaＧpertheeffectsofboronmudandCaF２ onsurfacetensionanddensityofCaOＧSiO２ＧB２O３ternaryslagsystemsarestudied
１ Experimental The measurementsofthesurfacetensionanddensitywereconductedusingahighＧtemperaturephysiＧcalfunctiondeterminator(RTWＧ０８China)whichwascomposedofahightemperatureheatingsystematemＧperaturemeasurementsystem andawatercoolingsystemTheexperimentalslagswerepreparedbypurechemicalreagentsTheCaOＧSiO２ＧB２O３systemwasconsideredtobethebasicslagsystemwhich
wasperformedatfixedbasicity(R＝２1049008５)andB２O３
content(１５)ThefluxingagentsareCaF２andboＧronmudwhoseadditionsare５１０and１５respectivelyInthisexperimentthechemicalcomＧpositionofboronmudwasanalyzedusingXＧrayfluＧorescence (XRF)spectroscopy (ARL ADVANTXIntelliPower４２００ThermoFisherAmerica)andtheresultisshowninTable１ThentheslagismixeduniformlyandgroundintofinepowderForeachslagspecimen１００goffinepowderwaschargedinＧtoagraphitecruciblewithsizeofϕ４０mmtimes９０mmThegraphitecruciblewasputintoafurnacewhosetemperaturewascontrolledbyacomputerDuringthemeltingprocesstheslagspecimenwasstirredbyaquartzrodAftertheslagspecimenwasmeltedcompletelythetemperaturewaskeptat１５００for３０ minThenthetemperatureofslagspecimenswasdecreasedThesurfacetensionanddensityweremeasuredat１３８０１４３０and１４８０respectivelyTheringdetachmentmethodwasadoptedtosurfacetensionmeasurementandtheArchimedeanmethodwasusedforslagdensitymeasurement
Table１ Mainchemicalcompositionofboronmudmass
SiO２ CaO MgO Fe２O３ B２O３ Al２O３ Na２O K２O
２７1049008１０ ４1049008２４ ５０1049008２８ ６1049008８５ ３1049008３４ ４1049008２６ ２1049008０８ １1049008８５
２ ResultsandDiscussion
２1049008１ EffectofboronmudandCaF２onsurfacetension ThesurfacetensionisoneofthemostimporＧtantphysicalpropertiesofmoltenslagwhichplaysacriticalroleinmeltingprocessItnotonlyinfluＧencestheinterfacereactionbutalsohasagreateffectontheseparationofslagandmetalremovalofinclusioninliquidsteeltheformationofnewphasetheslagfoamingaswellastheerosionbeＧtween slag and refractoryThe mostimportantphysicalpropertiesofmoldfluxincontinuouscastＧingprocessesincludesurfacetension (interfacialtension)viscosityandsolidificationtemperatureFurthermoresurfacetensionplaysasignificantroleinthereactionmechanismandtheresearchofphaseinterfacestructure２1049008１1049008１ Effectoftemperatureonsurfacetension TheeffectoftemperatureonsurfacetensionisshowninFig1049008１ItcanbeseenthatthesurfacetenＧsiondecreaseswithincreasingthetemperaturebutthechangeisnotobviousWhenthetemperatureriＧsesthethermalmotionandthespaceofparticlesincreasesothattheinteractingforcesbetweenpartiＧclesareweakenedwhichleadstothedecreaseinthesurfacetensionoftheslagHoweverthesurfacetensionincreaseswiththeincreaseofthekineticenＧ
Fig1049008１ Effectofboronmud(a)andCaF２ (b)onsurfacetensionofCaOＧSiO２ＧB２O３slagsystem
ergyoftheparticleasthetemperatureincreaseswhichcanmakecomplexionintheslagsurfacegointotheslagIngeneraltheeffectoftemperatureonsurfacetensionisnotevident２1049008１1049008２ Effectofboronmudonsurfacetension Fig1049008１(a)presentstheeffectofboronmudasfluxingagentsonsurfacetensionofCaOＧSiO２ＧB２O３
ternaryslagsystemsItindicatesthatthesurface
tensionisgraduallyenhancedwiththeincreaseofboronmudcontentThistendencyagreeswiththeresultsobtainedby Hanaoetal1049008[６]BasedonthetheoryofionmodeltheslagisionicstructuremeltconsistingofoxideThereforesurfacetensionoftheslagiscloselyrelatedtosurfacetensionofoxＧide[７]andthevalueofthesurfacetensionlargelydependsuponparticlenumberand momentamong
６４７ JournalofIronandSteelResearchInternational Vol1049008２１
theionsonthesurfaceofaunit[８]ItiswidelybeＧlievedthattheslagsconsistoftwokindsofionscationsandanions(simpleanionandcomplexaniＧon)AstheradiusofO２－isgreaterthanthatofcatＧionsthechangeofsurfacetensionofoxidemainlydependsontheforcebetweenO２－inthesurfaceandnearbycationsintheprocessofformingthemeltTable２showstheradiusandelectrostaticpotentialsofthemainionsintheslag[９]
Table２ Radiusandelectrostaticpotentialofions
Ion Ca２＋ Si４＋ O２－ F－ SiO４－
Radiusnm ０1049008１０６ ０1049008０４１ ０1049008１３２ ０1049008１３６ ０1049008２７９Electrostaticpotential １1049008８９ ９1049008７６ １1049008５２ ０1049008７４ １1049008４４
The maincomponentsoftheboron mudareMgOCaOFe２O３andB２O３SothecontentofO２－
whichisdissociatedoutinthemoltenslagincreaseswithincreasingthecontentofboronmudAthightemperatureacidoxideSiO２andoxygeniongenerＧatecomplexanionBesidesO２－ playsamoresignifＧicantroleinchangingsurfacetensionbecauseitsraＧdiusisfarlessthantheradiusofSixOz－
y anionConＧsequentlytheamountofthefreeO２－ getsmoreandmorewithraisingtheboron mudcontentwhichmakesthesurfacetensionincrease２1049008１1049008３ EffectofCaF２onsurfacetension Fig1049008１(b)revealstheresultofsurfacetensionbyusing５１０and１５ CaF２asthefluxingagentItcanbeseenthatthesurfacetensionoftheslagcontinuouslydecreaseswithincreasingthecontentofCaF２FromthepointofviewofiontheradiiofO２－ andF－ areclosesotheyhavesimilarproperＧtiesButtheelectrostaticpotentialofF－issmallerthanthatofO２－ soF－ canpushawayO２－ whenthecontentofCaF２increasesAsaresultsurface
tensionreducesasthenumberofparticlesonthesurfaceofaunitincreasesInadditionF－ cantaketheplaceofO２－tomakealargenumberofreticularorchaincompoundSixOz－
y disintegrateintosmallercompositeanionAsthetotalmomentofcomplexanionsissmallerthanthatofO２－ mostofthemareexcludedtothesurfaceofthesamplewhichcausesthedecreaseinsurfacetensionTheabovetwofactsmakethesurfacetensionfurtherreduceThemeasＧuredvaluesareingeneralagreementwiththosereＧportedbyNakamotoetal[１０] AtacertaintemperaturetheinterfacialtensionbetweenslagandmetalmainlydependsonthesurＧfacetensionofslagandtheinterfacialwettabilitybeＧtweenmoltensteelandslagItishardtomaketheslaggetintomoltensteelwhenthesurfacetensionincreaseswhichwillmaketheadhesionworksmalＧlerandthusimprovingsurfacetensionoftheslagcanreduceslagentrapment[１１]ThereforeusingboＧronmudasthefluxingagentisbetterthanCaF２
２1049008２ EffectofboronmudandCaF２ondensity DensityisoneofthefundamentalphysicalpropertiesathightemperaturesnotonlyfortheprocessoptimizationbutalsoforthemeasurementsofotherphysicalpropertiesMetalisoftendispersedintheformoftinydropletsintheslagInordertoseparatemetalfromtheslagandreducethelossoftheslagthegravityofthesuspendedmetaldropletmustbegreaterthanthebuoyancyandonlyinthiswaycanmetaldropletsbeseparatedfromtheslagAsaresultthevolumesizeoftheslagandterminalvelocityofmeltdropletaredeterminedbydensityoftheslag２1049008２1049008１ Effectoftemperatureondensity Fig1049008２showstheeffectoftemperatureondensity
Fig1049008２ Effectofboronmud(a)andCaF２ (b)ondensityofCaOＧSiO２ＧB２O３slagsystem
７４７Issue８ EffectofBoronMudandCaF２onSurfaceTensionandDensityofCaOＧSiO２ＧB２O３ TernarySlagSystems
ItcanbeseenthatdensityhaslinearrelationshiptothetemperaturenamelythedensitydecreaseswiththeincreaseoftemperatureThethermalmotionofionisenhancedowingtotheincreaseoftemperaＧturewhichresultsintheextensionofthedistanceamongtheionsandthentheinteractingforcesbeＧtweenionsareweakened２1049008２1049008２ Effectofboronmudondensity Fig1049008２(a)presentstheeffectofboronmudasfluxingagentondensityofCaOＧSiO２ＧB２O３ternaryslagsystemsItindicatesthatdensityhasareducedtrend withincreasing boron mudcontentanditchangesintherangeof３1049008２－３1049008９gcm３ThereasonisthattheincreaseofMgOandCaOintheboronmudcanmakedensitydecrease[１２]２1049008２1049008３ EffectofCaF２ondensity Fig1049008２(b)revealsthedifferentvaluesofdensitybyusing５１０and１５ CaF２asthefluxingagentAscanbeseenthevaluesofdensitytendtobesmallerwithincreasingCaF２andthechangerangeofdensityis３1049008４－４1049008１gcm３ Itiswellknownthatthenormalvalueofslagdensityisintherangeof２1049008８－３1049008２gcm３BycomＧparisontheslagdensitywillbemoreclosetothisvaluewhenusingboronmudasthefluxingagentFromthispointofviewboronmudisbetterthanCaF２
３ Conclusions (１)BothofthesurfacetensionanddensityofCaOＧSiO２ＧB２O３slagsystemdecreasewiththeincreaseoftemperature
(２)ForthebasicCaOＧSiO２ＧB２O３ slagsysＧtemthechangeofsurfacetensionisintherangeof０1049008３－０1049008６Nmwhen５－１０ CaF２isusedasfluＧxingagentwhereastherangeofsurfacetensionis０1049008４－０1049008６Nmwhenusing５－１０boronmudasthefluxingagentThustherearenosignificantdifferencesbetweenthem (３)Thevalueofdensitybyusingboronmudasthefluxingagentis３1049008２－３1049008９gcm３whichismoreclosetonormaldensitywhilethedensityvalＧueoftheslagis３1049008４－４1049008１gcm３ whenCaF２ wasusedasthefluxingagent
References
[１] Z1049008ZYangT1049008YCaoTOuWSunW1049008JZhuJWuhanEngInst２３(２０１１)No1049008３１８Ｇ２２
[２] HSutioRInoueISIJInt４２(２００２)９２１Ｇ９２９[３] G1049008RLiH1049008MWangQ1049008XDaiY1049008TZhaoJ1049008SLiJIron
SteelResInt１４(２００７)No1049008１２５Ｇ２８[４] H1049008MWangG1049008RLiQ1049008XDaiBLiX1049008JZhangG1049008M
ShiIronmakSteelmak３４(２００７)３５０Ｇ３５３[５] H1049008MWangL1049008LYangG1049008RLiXZhuJIronSteelRes
Int２０(２０１３)No1049008６２１Ｇ２４[６] MHanaoTTanakaMKawamotoKTakataniISIJInt
４７(２００７)９３５Ｇ９３９[７] Y1049008WMaoMetallurgicalMeltMetallurgicalIndustryPress
Beijing１９９４[８] H1049008MWangT1049008WZhangHZhuG1049008RLiY1049008QYanISIJ
Int５１(２０１１)７０２Ｇ７０７[９] J1049008HChiY1049008NGanMouldPowderNortheasternUniversity
PressShenyang１９９２[１０] MNakamotoTTanakaLHolappaHMarkoISIJInt
４７(２００７)２１１Ｇ２１６[１１] ZLiuShandongMetall２７(２００５)No1049008１３８Ｇ３９[１２] H1049008PSunKNakashimaKMoriISIJInt４６(２００６)４０７Ｇ４１２
８４７ JournalofIronandSteelResearchInternational Vol1049008２１
wasperformedatfixedbasicity(R＝２1049008５)andB２O３
content(１５)ThefluxingagentsareCaF２andboＧronmudwhoseadditionsare５１０and１５respectivelyInthisexperimentthechemicalcomＧpositionofboronmudwasanalyzedusingXＧrayfluＧorescence (XRF)spectroscopy (ARL ADVANTXIntelliPower４２００ThermoFisherAmerica)andtheresultisshowninTable１ThentheslagismixeduniformlyandgroundintofinepowderForeachslagspecimen１００goffinepowderwaschargedinＧtoagraphitecruciblewithsizeofϕ４０mmtimes９０mmThegraphitecruciblewasputintoafurnacewhosetemperaturewascontrolledbyacomputerDuringthemeltingprocesstheslagspecimenwasstirredbyaquartzrodAftertheslagspecimenwasmeltedcompletelythetemperaturewaskeptat１５００for３０ minThenthetemperatureofslagspecimenswasdecreasedThesurfacetensionanddensityweremeasuredat１３８０１４３０and１４８０respectivelyTheringdetachmentmethodwasadoptedtosurfacetensionmeasurementandtheArchimedeanmethodwasusedforslagdensitymeasurement
Table１ Mainchemicalcompositionofboronmudmass
SiO２ CaO MgO Fe２O３ B２O３ Al２O３ Na２O K２O
２７1049008１０ ４1049008２４ ５０1049008２８ ６1049008８５ ３1049008３４ ４1049008２６ ２1049008０８ １1049008８５
２ ResultsandDiscussion
２1049008１ EffectofboronmudandCaF２onsurfacetension ThesurfacetensionisoneofthemostimporＧtantphysicalpropertiesofmoltenslagwhichplaysacriticalroleinmeltingprocessItnotonlyinfluＧencestheinterfacereactionbutalsohasagreateffectontheseparationofslagandmetalremovalofinclusioninliquidsteeltheformationofnewphasetheslagfoamingaswellastheerosionbeＧtween slag and refractoryThe mostimportantphysicalpropertiesofmoldfluxincontinuouscastＧingprocessesincludesurfacetension (interfacialtension)viscosityandsolidificationtemperatureFurthermoresurfacetensionplaysasignificantroleinthereactionmechanismandtheresearchofphaseinterfacestructure２1049008１1049008１ Effectoftemperatureonsurfacetension TheeffectoftemperatureonsurfacetensionisshowninFig1049008１ItcanbeseenthatthesurfacetenＧsiondecreaseswithincreasingthetemperaturebutthechangeisnotobviousWhenthetemperatureriＧsesthethermalmotionandthespaceofparticlesincreasesothattheinteractingforcesbetweenpartiＧclesareweakenedwhichleadstothedecreaseinthesurfacetensionoftheslagHoweverthesurfacetensionincreaseswiththeincreaseofthekineticenＧ
Fig1049008１ Effectofboronmud(a)andCaF２ (b)onsurfacetensionofCaOＧSiO２ＧB２O３slagsystem
ergyoftheparticleasthetemperatureincreaseswhichcanmakecomplexionintheslagsurfacegointotheslagIngeneraltheeffectoftemperatureonsurfacetensionisnotevident２1049008１1049008２ Effectofboronmudonsurfacetension Fig1049008１(a)presentstheeffectofboronmudasfluxingagentsonsurfacetensionofCaOＧSiO２ＧB２O３
ternaryslagsystemsItindicatesthatthesurface
tensionisgraduallyenhancedwiththeincreaseofboronmudcontentThistendencyagreeswiththeresultsobtainedby Hanaoetal1049008[６]BasedonthetheoryofionmodeltheslagisionicstructuremeltconsistingofoxideThereforesurfacetensionoftheslagiscloselyrelatedtosurfacetensionofoxＧide[７]andthevalueofthesurfacetensionlargelydependsuponparticlenumberand momentamong
６４７ JournalofIronandSteelResearchInternational Vol1049008２１
theionsonthesurfaceofaunit[８]ItiswidelybeＧlievedthattheslagsconsistoftwokindsofionscationsandanions(simpleanionandcomplexaniＧon)AstheradiusofO２－isgreaterthanthatofcatＧionsthechangeofsurfacetensionofoxidemainlydependsontheforcebetweenO２－inthesurfaceandnearbycationsintheprocessofformingthemeltTable２showstheradiusandelectrostaticpotentialsofthemainionsintheslag[９]
Table２ Radiusandelectrostaticpotentialofions
Ion Ca２＋ Si４＋ O２－ F－ SiO４－
Radiusnm ０1049008１０６ ０1049008０４１ ０1049008１３２ ０1049008１３６ ０1049008２７９Electrostaticpotential １1049008８９ ９1049008７６ １1049008５２ ０1049008７４ １1049008４４
The maincomponentsoftheboron mudareMgOCaOFe２O３andB２O３SothecontentofO２－
whichisdissociatedoutinthemoltenslagincreaseswithincreasingthecontentofboronmudAthightemperatureacidoxideSiO２andoxygeniongenerＧatecomplexanionBesidesO２－ playsamoresignifＧicantroleinchangingsurfacetensionbecauseitsraＧdiusisfarlessthantheradiusofSixOz－
y anionConＧsequentlytheamountofthefreeO２－ getsmoreandmorewithraisingtheboron mudcontentwhichmakesthesurfacetensionincrease２1049008１1049008３ EffectofCaF２onsurfacetension Fig1049008１(b)revealstheresultofsurfacetensionbyusing５１０and１５ CaF２asthefluxingagentItcanbeseenthatthesurfacetensionoftheslagcontinuouslydecreaseswithincreasingthecontentofCaF２FromthepointofviewofiontheradiiofO２－ andF－ areclosesotheyhavesimilarproperＧtiesButtheelectrostaticpotentialofF－issmallerthanthatofO２－ soF－ canpushawayO２－ whenthecontentofCaF２increasesAsaresultsurface
tensionreducesasthenumberofparticlesonthesurfaceofaunitincreasesInadditionF－ cantaketheplaceofO２－tomakealargenumberofreticularorchaincompoundSixOz－
y disintegrateintosmallercompositeanionAsthetotalmomentofcomplexanionsissmallerthanthatofO２－ mostofthemareexcludedtothesurfaceofthesamplewhichcausesthedecreaseinsurfacetensionTheabovetwofactsmakethesurfacetensionfurtherreduceThemeasＧuredvaluesareingeneralagreementwiththosereＧportedbyNakamotoetal[１０] AtacertaintemperaturetheinterfacialtensionbetweenslagandmetalmainlydependsonthesurＧfacetensionofslagandtheinterfacialwettabilitybeＧtweenmoltensteelandslagItishardtomaketheslaggetintomoltensteelwhenthesurfacetensionincreaseswhichwillmaketheadhesionworksmalＧlerandthusimprovingsurfacetensionoftheslagcanreduceslagentrapment[１１]ThereforeusingboＧronmudasthefluxingagentisbetterthanCaF２
２1049008２ EffectofboronmudandCaF２ondensity DensityisoneofthefundamentalphysicalpropertiesathightemperaturesnotonlyfortheprocessoptimizationbutalsoforthemeasurementsofotherphysicalpropertiesMetalisoftendispersedintheformoftinydropletsintheslagInordertoseparatemetalfromtheslagandreducethelossoftheslagthegravityofthesuspendedmetaldropletmustbegreaterthanthebuoyancyandonlyinthiswaycanmetaldropletsbeseparatedfromtheslagAsaresultthevolumesizeoftheslagandterminalvelocityofmeltdropletaredeterminedbydensityoftheslag２1049008２1049008１ Effectoftemperatureondensity Fig1049008２showstheeffectoftemperatureondensity
Fig1049008２ Effectofboronmud(a)andCaF２ (b)ondensityofCaOＧSiO２ＧB２O３slagsystem
７４７Issue８ EffectofBoronMudandCaF２onSurfaceTensionandDensityofCaOＧSiO２ＧB２O３ TernarySlagSystems
ItcanbeseenthatdensityhaslinearrelationshiptothetemperaturenamelythedensitydecreaseswiththeincreaseoftemperatureThethermalmotionofionisenhancedowingtotheincreaseoftemperaＧturewhichresultsintheextensionofthedistanceamongtheionsandthentheinteractingforcesbeＧtweenionsareweakened２1049008２1049008２ Effectofboronmudondensity Fig1049008２(a)presentstheeffectofboronmudasfluxingagentondensityofCaOＧSiO２ＧB２O３ternaryslagsystemsItindicatesthatdensityhasareducedtrend withincreasing boron mudcontentanditchangesintherangeof３1049008２－３1049008９gcm３ThereasonisthattheincreaseofMgOandCaOintheboronmudcanmakedensitydecrease[１２]２1049008２1049008３ EffectofCaF２ondensity Fig1049008２(b)revealsthedifferentvaluesofdensitybyusing５１０and１５ CaF２asthefluxingagentAscanbeseenthevaluesofdensitytendtobesmallerwithincreasingCaF２andthechangerangeofdensityis３1049008４－４1049008１gcm３ Itiswellknownthatthenormalvalueofslagdensityisintherangeof２1049008８－３1049008２gcm３BycomＧparisontheslagdensitywillbemoreclosetothisvaluewhenusingboronmudasthefluxingagentFromthispointofviewboronmudisbetterthanCaF２
３ Conclusions (１)BothofthesurfacetensionanddensityofCaOＧSiO２ＧB２O３slagsystemdecreasewiththeincreaseoftemperature
(２)ForthebasicCaOＧSiO２ＧB２O３ slagsysＧtemthechangeofsurfacetensionisintherangeof０1049008３－０1049008６Nmwhen５－１０ CaF２isusedasfluＧxingagentwhereastherangeofsurfacetensionis０1049008４－０1049008６Nmwhenusing５－１０boronmudasthefluxingagentThustherearenosignificantdifferencesbetweenthem (３)Thevalueofdensitybyusingboronmudasthefluxingagentis３1049008２－３1049008９gcm３whichismoreclosetonormaldensitywhilethedensityvalＧueoftheslagis３1049008４－４1049008１gcm３ whenCaF２ wasusedasthefluxingagent
References
[１] Z1049008ZYangT1049008YCaoTOuWSunW1049008JZhuJWuhanEngInst２３(２０１１)No1049008３１８Ｇ２２
[２] HSutioRInoueISIJInt４２(２００２)９２１Ｇ９２９[３] G1049008RLiH1049008MWangQ1049008XDaiY1049008TZhaoJ1049008SLiJIron
SteelResInt１４(２００７)No1049008１２５Ｇ２８[４] H1049008MWangG1049008RLiQ1049008XDaiBLiX1049008JZhangG1049008M
ShiIronmakSteelmak３４(２００７)３５０Ｇ３５３[５] H1049008MWangL1049008LYangG1049008RLiXZhuJIronSteelRes
Int２０(２０１３)No1049008６２１Ｇ２４[６] MHanaoTTanakaMKawamotoKTakataniISIJInt
４７(２００７)９３５Ｇ９３９[７] Y1049008WMaoMetallurgicalMeltMetallurgicalIndustryPress
Beijing１９９４[８] H1049008MWangT1049008WZhangHZhuG1049008RLiY1049008QYanISIJ
Int５１(２０１１)７０２Ｇ７０７[９] J1049008HChiY1049008NGanMouldPowderNortheasternUniversity
PressShenyang１９９２[１０] MNakamotoTTanakaLHolappaHMarkoISIJInt
４７(２００７)２１１Ｇ２１６[１１] ZLiuShandongMetall２７(２００５)No1049008１３８Ｇ３９[１２] H1049008PSunKNakashimaKMoriISIJInt４６(２００６)４０７Ｇ４１２
８４７ JournalofIronandSteelResearchInternational Vol1049008２１
theionsonthesurfaceofaunit[８]ItiswidelybeＧlievedthattheslagsconsistoftwokindsofionscationsandanions(simpleanionandcomplexaniＧon)AstheradiusofO２－isgreaterthanthatofcatＧionsthechangeofsurfacetensionofoxidemainlydependsontheforcebetweenO２－inthesurfaceandnearbycationsintheprocessofformingthemeltTable２showstheradiusandelectrostaticpotentialsofthemainionsintheslag[９]
Table２ Radiusandelectrostaticpotentialofions
Ion Ca２＋ Si４＋ O２－ F－ SiO４－
Radiusnm ０1049008１０６ ０1049008０４１ ０1049008１３２ ０1049008１３６ ０1049008２７９Electrostaticpotential １1049008８９ ９1049008７６ １1049008５２ ０1049008７４ １1049008４４
The maincomponentsoftheboron mudareMgOCaOFe２O３andB２O３SothecontentofO２－
whichisdissociatedoutinthemoltenslagincreaseswithincreasingthecontentofboronmudAthightemperatureacidoxideSiO２andoxygeniongenerＧatecomplexanionBesidesO２－ playsamoresignifＧicantroleinchangingsurfacetensionbecauseitsraＧdiusisfarlessthantheradiusofSixOz－
y anionConＧsequentlytheamountofthefreeO２－ getsmoreandmorewithraisingtheboron mudcontentwhichmakesthesurfacetensionincrease２1049008１1049008３ EffectofCaF２onsurfacetension Fig1049008１(b)revealstheresultofsurfacetensionbyusing５１０and１５ CaF２asthefluxingagentItcanbeseenthatthesurfacetensionoftheslagcontinuouslydecreaseswithincreasingthecontentofCaF２FromthepointofviewofiontheradiiofO２－ andF－ areclosesotheyhavesimilarproperＧtiesButtheelectrostaticpotentialofF－issmallerthanthatofO２－ soF－ canpushawayO２－ whenthecontentofCaF２increasesAsaresultsurface
tensionreducesasthenumberofparticlesonthesurfaceofaunitincreasesInadditionF－ cantaketheplaceofO２－tomakealargenumberofreticularorchaincompoundSixOz－
y disintegrateintosmallercompositeanionAsthetotalmomentofcomplexanionsissmallerthanthatofO２－ mostofthemareexcludedtothesurfaceofthesamplewhichcausesthedecreaseinsurfacetensionTheabovetwofactsmakethesurfacetensionfurtherreduceThemeasＧuredvaluesareingeneralagreementwiththosereＧportedbyNakamotoetal[１０] AtacertaintemperaturetheinterfacialtensionbetweenslagandmetalmainlydependsonthesurＧfacetensionofslagandtheinterfacialwettabilitybeＧtweenmoltensteelandslagItishardtomaketheslaggetintomoltensteelwhenthesurfacetensionincreaseswhichwillmaketheadhesionworksmalＧlerandthusimprovingsurfacetensionoftheslagcanreduceslagentrapment[１１]ThereforeusingboＧronmudasthefluxingagentisbetterthanCaF２
２1049008２ EffectofboronmudandCaF２ondensity DensityisoneofthefundamentalphysicalpropertiesathightemperaturesnotonlyfortheprocessoptimizationbutalsoforthemeasurementsofotherphysicalpropertiesMetalisoftendispersedintheformoftinydropletsintheslagInordertoseparatemetalfromtheslagandreducethelossoftheslagthegravityofthesuspendedmetaldropletmustbegreaterthanthebuoyancyandonlyinthiswaycanmetaldropletsbeseparatedfromtheslagAsaresultthevolumesizeoftheslagandterminalvelocityofmeltdropletaredeterminedbydensityoftheslag２1049008２1049008１ Effectoftemperatureondensity Fig1049008２showstheeffectoftemperatureondensity
Fig1049008２ Effectofboronmud(a)andCaF２ (b)ondensityofCaOＧSiO２ＧB２O３slagsystem
７４７Issue８ EffectofBoronMudandCaF２onSurfaceTensionandDensityofCaOＧSiO２ＧB２O３ TernarySlagSystems
ItcanbeseenthatdensityhaslinearrelationshiptothetemperaturenamelythedensitydecreaseswiththeincreaseoftemperatureThethermalmotionofionisenhancedowingtotheincreaseoftemperaＧturewhichresultsintheextensionofthedistanceamongtheionsandthentheinteractingforcesbeＧtweenionsareweakened２1049008２1049008２ Effectofboronmudondensity Fig1049008２(a)presentstheeffectofboronmudasfluxingagentondensityofCaOＧSiO２ＧB２O３ternaryslagsystemsItindicatesthatdensityhasareducedtrend withincreasing boron mudcontentanditchangesintherangeof３1049008２－３1049008９gcm３ThereasonisthattheincreaseofMgOandCaOintheboronmudcanmakedensitydecrease[１２]２1049008２1049008３ EffectofCaF２ondensity Fig1049008２(b)revealsthedifferentvaluesofdensitybyusing５１０and１５ CaF２asthefluxingagentAscanbeseenthevaluesofdensitytendtobesmallerwithincreasingCaF２andthechangerangeofdensityis３1049008４－４1049008１gcm３ Itiswellknownthatthenormalvalueofslagdensityisintherangeof２1049008８－３1049008２gcm３BycomＧparisontheslagdensitywillbemoreclosetothisvaluewhenusingboronmudasthefluxingagentFromthispointofviewboronmudisbetterthanCaF２
３ Conclusions (１)BothofthesurfacetensionanddensityofCaOＧSiO２ＧB２O３slagsystemdecreasewiththeincreaseoftemperature
(２)ForthebasicCaOＧSiO２ＧB２O３ slagsysＧtemthechangeofsurfacetensionisintherangeof０1049008３－０1049008６Nmwhen５－１０ CaF２isusedasfluＧxingagentwhereastherangeofsurfacetensionis０1049008４－０1049008６Nmwhenusing５－１０boronmudasthefluxingagentThustherearenosignificantdifferencesbetweenthem (３)Thevalueofdensitybyusingboronmudasthefluxingagentis３1049008２－３1049008９gcm３whichismoreclosetonormaldensitywhilethedensityvalＧueoftheslagis３1049008４－４1049008１gcm３ whenCaF２ wasusedasthefluxingagent
References
[１] Z1049008ZYangT1049008YCaoTOuWSunW1049008JZhuJWuhanEngInst２３(２０１１)No1049008３１８Ｇ２２
[２] HSutioRInoueISIJInt４２(２００２)９２１Ｇ９２９[３] G1049008RLiH1049008MWangQ1049008XDaiY1049008TZhaoJ1049008SLiJIron
SteelResInt１４(２００７)No1049008１２５Ｇ２８[４] H1049008MWangG1049008RLiQ1049008XDaiBLiX1049008JZhangG1049008M
ShiIronmakSteelmak３４(２００７)３５０Ｇ３５３[５] H1049008MWangL1049008LYangG1049008RLiXZhuJIronSteelRes
Int２０(２０１３)No1049008６２１Ｇ２４[６] MHanaoTTanakaMKawamotoKTakataniISIJInt
４７(２００７)９３５Ｇ９３９[７] Y1049008WMaoMetallurgicalMeltMetallurgicalIndustryPress
Beijing１９９４[８] H1049008MWangT1049008WZhangHZhuG1049008RLiY1049008QYanISIJ
Int５１(２０１１)７０２Ｇ７０７[９] J1049008HChiY1049008NGanMouldPowderNortheasternUniversity
PressShenyang１９９２[１０] MNakamotoTTanakaLHolappaHMarkoISIJInt
４７(２００７)２１１Ｇ２１６[１１] ZLiuShandongMetall２７(２００５)No1049008１３８Ｇ３９[１２] H1049008PSunKNakashimaKMoriISIJInt４６(２００６)４０７Ｇ４１２
８４７ JournalofIronandSteelResearchInternational Vol1049008２１
ItcanbeseenthatdensityhaslinearrelationshiptothetemperaturenamelythedensitydecreaseswiththeincreaseoftemperatureThethermalmotionofionisenhancedowingtotheincreaseoftemperaＧturewhichresultsintheextensionofthedistanceamongtheionsandthentheinteractingforcesbeＧtweenionsareweakened２1049008２1049008２ Effectofboronmudondensity Fig1049008２(a)presentstheeffectofboronmudasfluxingagentondensityofCaOＧSiO２ＧB２O３ternaryslagsystemsItindicatesthatdensityhasareducedtrend withincreasing boron mudcontentanditchangesintherangeof３1049008２－３1049008９gcm３ThereasonisthattheincreaseofMgOandCaOintheboronmudcanmakedensitydecrease[１２]２1049008２1049008３ EffectofCaF２ondensity Fig1049008２(b)revealsthedifferentvaluesofdensitybyusing５１０and１５ CaF２asthefluxingagentAscanbeseenthevaluesofdensitytendtobesmallerwithincreasingCaF２andthechangerangeofdensityis３1049008４－４1049008１gcm３ Itiswellknownthatthenormalvalueofslagdensityisintherangeof２1049008８－３1049008２gcm３BycomＧparisontheslagdensitywillbemoreclosetothisvaluewhenusingboronmudasthefluxingagentFromthispointofviewboronmudisbetterthanCaF２
３ Conclusions (１)BothofthesurfacetensionanddensityofCaOＧSiO２ＧB２O３slagsystemdecreasewiththeincreaseoftemperature
(２)ForthebasicCaOＧSiO２ＧB２O３ slagsysＧtemthechangeofsurfacetensionisintherangeof０1049008３－０1049008６Nmwhen５－１０ CaF２isusedasfluＧxingagentwhereastherangeofsurfacetensionis０1049008４－０1049008６Nmwhenusing５－１０boronmudasthefluxingagentThustherearenosignificantdifferencesbetweenthem (３)Thevalueofdensitybyusingboronmudasthefluxingagentis３1049008２－３1049008９gcm３whichismoreclosetonormaldensitywhilethedensityvalＧueoftheslagis３1049008４－４1049008１gcm３ whenCaF２ wasusedasthefluxingagent
References
[１] Z1049008ZYangT1049008YCaoTOuWSunW1049008JZhuJWuhanEngInst２３(２０１１)No1049008３１８Ｇ２２
[２] HSutioRInoueISIJInt４２(２００２)９２１Ｇ９２９[３] G1049008RLiH1049008MWangQ1049008XDaiY1049008TZhaoJ1049008SLiJIron
SteelResInt１４(２００７)No1049008１２５Ｇ２８[４] H1049008MWangG1049008RLiQ1049008XDaiBLiX1049008JZhangG1049008M
ShiIronmakSteelmak３４(２００７)３５０Ｇ３５３[５] H1049008MWangL1049008LYangG1049008RLiXZhuJIronSteelRes
Int２０(２０１３)No1049008６２１Ｇ２４[６] MHanaoTTanakaMKawamotoKTakataniISIJInt
４７(２００７)９３５Ｇ９３９[７] Y1049008WMaoMetallurgicalMeltMetallurgicalIndustryPress
Beijing１９９４[８] H1049008MWangT1049008WZhangHZhuG1049008RLiY1049008QYanISIJ
Int５１(２０１１)７０２Ｇ７０７[９] J1049008HChiY1049008NGanMouldPowderNortheasternUniversity
PressShenyang１９９２[１０] MNakamotoTTanakaLHolappaHMarkoISIJInt
４７(２００７)２１１Ｇ２１６[１１] ZLiuShandongMetall２７(２００５)No1049008１３８Ｇ３９[１２] H1049008PSunKNakashimaKMoriISIJInt４６(２００６)４０７Ｇ４１２
８４７ JournalofIronandSteelResearchInternational Vol1049008２１
