2023年全國(guó)碩士研究生考試考研英語一試題真題（含答案詳解+作文范文）_第1頁
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1、DesulfurizationDeoxidationofMoltenIronwithInSituProducedMagnesiumVapJianYANGMamuKUWABARAZhongzhuLIUKeijiOKUMURAMasamichiSANO(GraduateSchoolofEngineeringNagoyaUniversityNagoyaAichiken4648603Japan)Abstract:Novelhotmetaldes

2、ulfurizationmoltensteeldesulfurizaitondeoxidationprocesseshavebeendevelopedwithmagnesiumvapproducedinsitubyaluminothermicreductionofmagnesiumoxide.Thecheapermagnesiumoxideinsteadofmagnesiummetalisusedasthesecondarysource

3、ofmagnesiumsothatthecostofmagnesiumdesulfurizaitondeoxidationisgreatlyreduced.MgOAlpelletsaregedintoatubewhichisimmersedintothemolteniron.Heatedbyheatconductionfromthemoltenironmagnesiumoxideinthepelletsisreducedbyalumin

4、iumtoproducemagnesiumvapwhichisinjecteddirectlyintothemoltenirontogetherwithArcarriergastoreactwithsulfuroxygendissolvedinit.Thedesulfurizationdeoxidationprocessesareacterizedbyeasysafeoperationlowcostbothofthesulfuroxyg

5、enconcentrationsinthemoltenironcanbequicklydecreasedtoaverylowlevel.TherefiningefficiencyofmagnesiumcanbegreatlyimprovedbyadjustingthemagnesiumpartialpressureintheinjectedbubbletotheoptimumvaluethroughchangingtheArcarrie

6、rgasflowrate.TheMgOinclusionsfmedinthedeoxidationprocessareusuallyverysmall.Meovertheycanberapidlyremovedbyadheringtothesurfaceoftherisingbubbles.Keywds:DesulfurizationDeoxidationMagnesiumvapMgOinclusionsMoltenironAlumin

7、othermicreduction1IntroductionItiswellknownthatmagnesiumisastrongdesulfruizationdeoxidationreagentinironsteelmakingprocesses.12)Asadesulfurizermagnesiumhastheadvantagesthatitcanpromptlyreducethesulfurcontentinhotmetaltoa

8、nultralowlevelthenecessaryamountofslagismarkedlycutdownwhichnotonlyisfavabletotheenvironmentbutalsoreducesthetemperatureduringthetreatment.39)WithmagnesiumasadeoxidationreagenttheMgOinclusionsfmedinthedeoxidationprocessa

9、reusuallysosmallthattheyarenotharmfultothemechanicalpropertiesofsteelproduct.1013)Howeversincethenmalboilingpointofmagnesiumof1380Kismuchlowerthanthetemperatureofironsteelmakingrefiningwithmagnesiumhasthedrawbacksoflowre

10、finingefficiencysafetyproblemduetoviolentmagnesiumvapization.Furthermemetalmagnesiumishighinprice.Inthepresentstudyanewmethodofdesulfurizationdeoxidationofmoltenironwithmagnesiumvapproducedinsitubyaluminothermicreduction

11、ofmagnesiumoxideisproposed.Thecheapermagnesiumoxideinsteadofmagnesiummetalisusedasthesecondarysourceofmagnesiumsothatthecostofdesulfurizaitondeoxidationwithmagnesiumisgreatlyreduced.Pelletsmadeofmixtureofmagnesiumoxideal

12、uminumpowdersaregedintoanimmersiontube.Theproducedmagnesiumvapisinjecteddirectlyintothemelt.Theeffectsofexperimentaltemperaturecarriergasflowrateontherefiningratearestudied.Akiicmodeldescribingtherateofdesulfurizationdeo

13、xidaionwithmagnesiumisproposedtoexplaintheexperimentalresults.Anovelmethodofimprovingtherefiningefficiencyofmagnesiumisproposedbyadjustingthemagnesiummolarratiointhebubbletotheoptimumvaluethroughchangingcarriergasflowrat

14、e.The3(MgO?Al2O3)(s)2Al(l)=3Mg(g)4Al2O3(s)(3)Indertoexpressthedegreeofreductionthereductionefficiencyofmagnesiumoxide(ηRMgO)isintroducedwhichisdefinedastheratioofthereducedMgOmass(WRMgO)totheinitialMgOmassinthepellet(W0M

15、gO).ηRMgO=(WRMgOW0MgO)?100(%)(4)4KiicsofDesulfurizationDeoxidationDesulfurizationdeoxidationwithmagnesiumvapcanbewrittenasMg(g)X=MgX(s)(5)whereXdenotesdissolvedsulfuroxygen.Acommonbasisisrequiredfadetailedkiicanalysisofd

16、esulfurizationofmoltenirondeoxidationofmoltensteelwithmagnesiumvapproducedinsitubyaluminothermicreductionofmagnesiumoxide.Intheseprocessesthedesulfurizationdeoxidationsitesareassumedonthebubblesurfacetheratecontrollingst

17、epsarethemasstransferofthegaseousmagnesiumthedissolvedmagnesiumX(sulfuroxygen)tothebubblesurface.Theotherassumptionsareasfollows:ThecontentofXthetemperatureinmeltareunifm.Thebubbleisofsphericalshapethereisnodisintegratio

18、ncoalescenceduringtherisingprocessofbubbles.Onthebasisoftheaboveassumptionsonecanobtainthefollowingequationsfasinglebubble.(6))(RddiMgMgMggBMgPPATktn???(7))[%X]([%X]100ddiXmXlX???MρAktn(8))][%Mg%Mg]([100ddMgmMgllMgiMρAkt

19、n???wherenxnMglarethenumberofmolesofsulfuroxygenmagnesiuminthemeltnMgBisthenumberofmolesofmagnesiuminthebubbleklXklMgarethemasstransfercoefficientsofsulfuroxygenmagnesiuminthemeltkgMgisthemasstransfercoefficientofmagnesi

20、uminthebubble[%X][%X]iarethesulfuroxygenconcentrationsinthemeltonthebubblesurface[%Mg][%Mg]iarethemagnesiumconcentrationsinthemeltonthebubblesurfacePMgPMgiarethemagnesiumpartialpressuresinthebubbleonthebubblesurfaceMXMMg

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