24 11 2012 11 JournalofIronandSteelResearch Vol.24 No.11 November 2012 CO Fe2O3 ( 100083) : CO Fe2O3 ; Fe2O3 Fe3O4 FeO ; FeO Fe 100% FeO Fe : ; ; ; :A :1001-0963(2012)11-0023-06 Micro-BehaviorofthePrecipitationofMetalicFeinthe ReductionofFe2O3 UnderCOAtmosphere ZHAOZhi-long TANG Hui-qing GUOZhan-cheng (StateKeyLaboratoryofAdvanced MetalurgyUniversityofScienceandTechnologyBeijingBeijing100083China) Abstract:Theprecipitationmorphologyofmetalicironandevolutionprocessofmineralogicalstructureatgas-solid interfaceduringreductionwerestudiedbyinsituobservationandthermalanalysistoidentifytherelationshipsbe- tweentheprecipitationmorphologyofmetalicironand micro-structurestickingproperty.resultsindicatethat metalicironismainlyformedasironwhiskerwithfibrousshapeinthefe2o3reductionundercoatmosphere andreductionrateismainreasonforthediferenceofthismorphology.intheconversionoffe2o3 Fe3O4 FeO thevolumeischangedjustduetolaticetransformationalsoaccompanyingcrackandholetakeplaceandnoiron whiskersform.thenucleationandgrowthofironwhiskers(100% pureiron)proceedintheconversionoffeo Fe.Thereforeinordertoavoidtheformationofironwhiskerstheorientedmigrationofatomironshouldbein- hibitedintheconversionoffeo Fe. Keywords:ironmaking;insituobservation;gaseousreduction;ironwhisker;sticking [1-2] [2-5] 3 [1-5] : (50834007) : (1984 ) ; E-mail:zzl123222@126.com; :2012-01-01
24 24 1 1.1 Linkam TS1500 ( 1~130 /min ±1 ) Zeiss StereoDiscoveryV20 (100~1300 ) 1 STA PT1600 (1600 2 50MPa) Fig.2 ImageofflakyFe2O3inhigh temperaturestereomicroscope N 2 TG-DTA 1 Fig.1 Experimentalapparatusofinsituobservation 1.2 150μm d 10~60μm h 2~4μm d/h 10 Fe2O3 Fe 2O 3 50 /min 30min 60 /min 1000 1 Fe 2O 3 10 /min 10MPa 30min 2 Fe(NO 3 ) 3 9H 2O Fe(NO 3 ) 3 2.1 ( =6mmh=0.6mm) 1000 CO 60min Fe 2O 3 3 700 Fe(NO 3 ) 3 Fe 2O 3 Fe 2O 3 2 Fe 2O 3 D 30~ FeO Fe 1.3 10min 700 800 900 800 CO+CO 2 N 2 CO+CO 2+N 2 40mL/min CO CO 2 4 1 N 2 0 20%( )
11 :CO Fe2O3 25 3 Fe2O3 Fig.3 ResultsofinsituobservationforFe2O3reductionatdiferenttemperatures 5min 30min 800 20~30min [6-7] 800 60min 3000 SEM ( 4)700 ;800 900 ;900 2~3min 10min 1~2μm CO 900 4 (a)700 ; (b)800 ; (c)900 30min SEM Fig.4 SEMimagesafterthereductionfor30minatdiferenttemperatures 2.2 5 800 CO CO
26 24 5 ( ) Fe2O3 (800 ) Fig.5 ResultsofinsituobservationsinFe2O3reductionatreducedgaswithdiferentconcentrations (CO+CO 2 ) 100% 8min N 2 70% 9min CO 30min 3000 SEM ( 6) CO+CO 2 100% ; N 2 CO+CO 2 70% 1 Fe2O3 Fe3O4; 2 Fe3O4 FeO; 3 FeO Fe 7 CO Fe2O3 TG-DTA CO Fig.7 CurvesofTG-DTAintheFe2O3reductionwithCO 6 (a)co+co2 100%; (b)co+co2 70% CO SEM (800 ) Fig.6 SEMimagesonthegrowthofiron whiskersatcoconcentrations(800 ) 2.3 CO TG DTA Fe 2O 3 Fe 3O 4 30s 3.3% Fe 3O 4 Fe 3O 4 FeO DTA 2min Fe 3O 4 FeO 50s DTA FeO Fe 5min TG FeO Fe FeO Fe FeO Fe CO TG CO 5min 83% CO+CO 2 Fe 2O 3 7 1min
11 :CO Fe2O3 27 30min 90% 800 TG-DTA 3 3.1 CO Fe 3O 4 Fe 2O 3 Fe 3O 4 CO Fe 2O 3 Fe 3O 4 8.6% Janowski [8] Roler [9] Schiler [5] SEM CO 30s 40~50s ( 8) Fe 2O 3 Fe 3O 4 Fe 2O 3 Fe 3O 4 FeO (a)4min; (b)4.5min; (c)5min; (d)10min; (e)30min 8 Fig.8 Morphologyevolutionprocesofironoxidesinthereduction TG Fe 2O 3 Fe 3O 4 Fe 3O 4 FeO FeO Fe Fe 2O 3 ( 9) Hayes [10] Swann [11] Nasr [12] Fe 2O 3 Fe 3O 4 Swann Fe 3O 4 Becker [13] Kashiwaya [14] X (0001) H (111) M Fe 2O 3 Fe 3O 4 (a)fe2o3; (b)fe2o3 Fe3O4; (c) ; (d) 9 CO Fig.9 CracksandholesinthereductionwithCO
28 24 3.2 CO CO Fe 2O 3 Fe 2O 3 Fe 3O 4 FeO [ 10(a)] FeO Fe 10(b) ( 2) ( 1) FeO FeO Fe FeO 11 FeO Fe Fig.11 Diagrammaticdrawingonformationmechanismof ironwhiskersintheconversionoffeo Fe 4 10 (a) (b) SEM Fig.10 SEManalysisintheformation procesofironwhiskers FeO Fe Fe 2O 3 Fe 3O 4 FeO FeO FeO Fe ( 11) Fe 3O 4 FeO FeO Fe ; FeO Fe : FeO Fe ja200410(4):309. Aachen1996. FeO Fe FeO Fe 1) 2) 1μm 3)CO Fe 2O 3 Fe 3O 4 Fe 3O 4 FeO FeO Fe Fe 2O 3 Fe 3O 4 FeO FeO Fe 100% Fe 2O 3 Fe 3O 4 FeO Fe 4) CO [1] MirkoKHeinrich-W G.TheStickingProblem DuringDirect ReductionofFineIronOreintheFluidizedBed[J].Metalurgi- [2] DegelR.EisenerzreduktioninderWirbelschihtMitWasserst- ofreichem Gas:Sticking und Ansatz [D].Iehk:RWTH [3] Gudenau H WHirsch MDeneckeHetal.TheDirectRe- ductionofironorebythefluidizedbedunderhydrogenat- mosphere[j].stahlundeisen1997117(4):91. ( 62 )
62 24 4 : [1] JuliusETheissen WBlockFR.FunctionandApplicationof ElectromagneticSlagDetectionSystem [J].WorldSteeland Metalworking1987107(9):56. [2] 4 [J]. 201022(7):59. tional:germany200225(1):52. Vision200459(2):167. [5] 3~5s 100% [6] 200314(8):1388. [7] 2010(2): 58.. [3] Rau HRopV.ApplicationofThermographicSlagDetection [J].Ingo MPT MetalurgicalPlantand TechnologyInterna- [4] FelzenszwalbP FHutenlocherD P.EficientGraph-Based ImageSegmentation [J].InternationalJournalofComputer. [J]. 200416(2):168.. [J].. [J]. 櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄櫄 ( 28 ) [4] Gudenau H WFangJHirataTetal.FluidizedBedReduc- tionasthepre-stepofsmeltingreduction [J].SteelRes 198960(314):138. [5] SchilerM.DieMikromorphologiederEisenphasealsFolgeder ReduktionvonEisenoxiden[D].Iehk:RWTH Aachen1987. [6] BonaldeAHenriquezAManriqueM.KineticAnalysisof theironoxidereductionusinghydrogen-carbon Monoxide MixturesasReducingAgent[J].ISIJInternational200545 (9):1255. [7] BartelsMLin W GNijenhuisJetal.Agglomerationin FluidizedBedsatHighTemperatures:MechanismsDetection andprevention [J].ProgressinEnergyandCombustionSci- ence200834(5):633. [8] JanowakiJJWyderko-DelektaMSadowskiA.Morphology ofhematiteto MagnetiteReductionZone[J].SteelResearch 199566(4):135. [9] RolerP W.TheoreticalVolumeDecreaseonReductionof Hematiteto Magnetite[J].TransactionsoftheIronandSteel InstituteofJapan198626(9):834. [10] HayesP CGrievesonP.Micro-StructuralChangesonthe Reduction of Hematite to Magnetite [J]. Metalurgical TransactionsB198112(3):579. [11] SwannPRTigheNJ.HighVoltageMicroscopyoftheRe- ductionofhematiteto Magnetite[J].MetalurgicalTransac- tionsb19778(30):479. [12] NasrMI.EfectofTemperatureandTimeontheStructure ofmagnetitecompacts [J].ScandinavianJournalofMetal- lurgy199423(5-6):209. [13] BeckerPHeizmannJJBaroR.RelationsTopotaxiques EntredesCristauxNaturelsD hématiteetlemagnétitequi enestissueparréductionàbassetempérature[j].journal ofappliedcrystalography197710(2):77. [14] KashiwayaYYamaguchiYKinoshitaHetal.InSituOb- servationofreductionbehaviorofhematite WithSolidCar- bonandcrystalographicorientationbetween Hematiteand Magnetite[J].ISIJInternational200747(2):226.