硕士论文-磁铁精矿的微波烧结研究

重庆大学硕士学位论文磁铁精矿的微波烧结研究姓名：任伟申请学位级别：硕士专业：冶金工程指导教师：白晨光20060401I7035CO2“”Fe3O42.45GHz1000WFe3O4100g15120067/min15100g201%2%3%10001%3%6003010CaO1.52.5100g20100013002.52.5200g400g600g201200600g800N2100g2.52.73.0201200Fe3O4100g20Fe3O4IIABSTRACTSinterisoneofthemainrawmaterialsinblastfurnaceiron-makingprocess,whichtakesabout70%intheiron-bearingmaterials.Generally,withanair-exhaustedorair-blastmethod,theironoreandothermaterialssuchascalciumaresinteredtomeettherequestofprocessing.Buttwoproblemscannotbeovercame.Firstly,theconventionalsinteringprocessneeds35percentcarbon,anditwillexhaustedalargemountsofcoalresource.Secondly,alargeamountofpollutedgaseswouldbeproducedduetotheuseofcoal,andthisisopponenttothe“cleanproduction”.Soitisnecessarytodevelopaprocessthatmayovercometheproblems,whilethemicrowaveisavaluablemethod.Microwaveheatingisanovelheatingmethod,whichhasmanypotentialproperties,suchasselectiveheating,volumetricheating,clean,easytocontrolandrapidheating,andithasappliedinmanyfields,especially,ithasattainedagreatachievementinsomeaspects.Asformagneticconcentrates-oneoftherawmaterialsmentioned,whosemaincompositionisFe3O4,ismicrowave-absorbingmaterial,andcanbeheatedrapidlyundermicrowaveirradiation.Forthegoaltoovercometheproblemsduetothefuelandpollutionofconventionalsintering,aprimarystudyaboutmicrowavesinteringofmagnetiteconcentrateshasbeendone.Themechanismofmicrowaveheatingwasintroduced,andinlab-scale,withamicrowaveoven(2.45GHz,100W)andperiodicaltemperaturemeasurement,intheconditionofdifferentirradiationtime,carbonaddition,basicity,samplemass,inertatmosphereandFe3O4addition,themicrowavesinteringpropertiesofthreemagnetiteconcentrates(Localconcentrates,ZhiLiconcentrates,V-Ticoncentrates)werestudied.Itwasshownthat:intheprocessofmicrowaveheatingmagnetiteconcentrates,thetemperaturecanreach1200in15minutes,andtheaveragetemperatureratewasabout67/min,thenthetemperaturechangebecamelowerinthistemperature;Withasameirradiationtime(20min),allthetemperatureofthesamplewith1%,2%,3%carbonwerelowerthan1000,thetemperatureof3%carbonsample,comparaedwiththesamplewith1%carbon,thetemperaturechangeisabout600,30,10forlocalconcentrates,ZhiLiconcentrates,V-Ticoncentratesrespectively.ToaddCaOtomagnetiteconcentratestoformthesamplewith1.52.5basicity,withaheatingtimeof20min,thetemperatureisamong1000to1300,especially,thelocalconcntreateswitha2.5IIIbasicity,alargemountofliquidphasegenerated;Withasamplemassof200g,400g,600g,thetmperaturewerealllessthan1200,andone600gsamplecanbelower800;IntheatmosphereofN2,thesamplewiththebasicityof2.5,2.7,3.0wereallabout1200;ToaddFe3O4tomagnetiteconcentres,comparedwiththepuremagnetiteconcentrates,therewaslessliquidphasegenerated.Keywords:Microwave,Sinter,MagnetiteConcentrates1111.11.1.170%90%[1]9.815.7kPa11001500[2]1.1.2122005300,28800m2[3]20043.25[4]1.7FeO10%1.1Table1.1sinterproductionfrom1990to20041990199119961997199820022004/t80009654142001510016300226003250035SO2CO21.1131.11980-1996CO2[5]Fig.1.1carbondioxideemissionsofsteelproductioninChina,1980-19961.2300MHz300GHz11000mm1.2915MHz2.45GHz5.8GHz24.124GHz[6]2.45GHz3×108m/s12.24cm24.5/1.3FeCuAl1.2[7]Fig.1.2wavesandtheirwavelength141.3Fig.1.3threetypesofmicrowaveheatingmode1.2.1100/s1.4151.4Fig.1.4heatingpatternsinconventionalandmicrowavefurnace1.2.2HACa10(PO4)4(OH)2BST(Ba0.65Sr0.35TiO3)PTC[8-12]TiO2NixMn3-xO4(0.5≤x≤1)LiMn2O4HgSCuS[13-19]ZSM5βSBA16TS2LSX[20-28]90[29-34][35]AuCuU[36-39]Cr[40][41]1.316Fe3O42722.12.1Fig.2.1principleofmicrowavedielectricheating2.1[42]10-15s10-16s2810-12s10-13s“”2.22.2.1jdisconjjj+=29EiiErrie)'()(0εεϖεσσ+++(2-1)conjdisjeσiσ)'(0rriεεε+20tan'2EfjEPreδεεπ==(2-2)ePf'0rεεδtanE')[tan0εεϖεσσδ++=ie(2-3)2-3'tanεεδ=2-4300MHz300GHz10-1410-15s[43]2.22102.2Fig.2.2theschematicsketchofpolarizabilitydependenceonfrequence2.2.2δ∫=TmHdBTP01(2-5))cos(tHeHHmiwtmϖ==(2-6))cos(sincoscos)cos(2πϖδϖδδϖ−+=−=tBtBtBBmmm(2-7)∫−=TmmmtdBtHTP0)cos()cos(1δϖϖ∫−−=TmmtdtBtHT0)()sin()cos(1ϖδϖϖδϖsin21mmBH=(2-8)'''sincos00001rrHBHBiHBriieHBmmmmmmµµδδµµµδµµ−=−===−(2-9)20tan'HfPrmδµµπ=(2-10)mPHmHB211mBδϖµ'µ''µf1012Hz2.2.32eionconEEjjEjPσ××=2-11conPjEionjejσ2.31012HzconmePPPPtotal2-12212totalPePmPconP2.3.1mePPP]||tan||tan[22'02'0HEfRRΦ+=µµδεεπ2-13fε0μ0εR‘μR‘tanδtanφEH12120etotaltan'2PEfPrδεεπ==(2-14)2.3.2mePPPtotal2-15totalP213ePmPωτεεεωεi1*+−∞∞s2-16ωε*ω∞εsεP20220()[]1sEεεωτσωεωεωτ∞−=++=22022()[]1sEεεωετσωτ∞−++2-17Tτ221ωτ2-17202||])([EPsτεωεεσ∞−+2-18[44]σ=exp()iiEAkT−∑2-19ττ=0τexpH/kT(2-18)220000[exp()exp()]EHPABEkTkTω=−+2-20[45]31433.13.1.1Fe3O4CaOZLJKGNJKFTJK3.1C99.9%Fe3O4CaO99.93.1Table3.1thecompositionofthemagnetiteconcentrates/g/gTFe/%SiO2/%CaO/%S/%FeO/%ZLJK100.4669.602.150.200.05323.920.09GNJK100.6764.406.251.300.14327.050.21FTJK100.3852.004.252.000.11020.700.473.1.23.13.1Fig.3.1thesketchformicrowavesinteringexperiment31510008mm1000W1000W666W333W2.45GHz329mm×215mm×329mma×b×d3.23.2Fig.3.2thestructureanddimensionofovencavity(3.3)3.3Fig.3.3thesketchofmicrowaveoven3163.43.53.6TE10FDTD3.4Fig.3.4Fielddistributionsincylinderwaveguides3.5Fig.3.5Fielddistributionsinrecta