Chapter two1(2007)

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1、ChaptertwoExtractionandRefiningofMetals冶金Extractionprocessesmaybedividedintothreemaingroups:a)Pyrometallurgicalmethods火法冶金inwhichheatisusedtoachievedecompositionofthevaluablemetalcompound.b)Hydrometallurgicalmethods湿法冶金whichinvolvetakingthevaluablemetalintoaqueoussolutionfollowe

2、dbyitsrecoveryfromthesolution.c)Electrometallurgicalmethods电冶金inwhichelectrolysisisusedtodecomposeafusedcompoundofthevaluablemetal.Pyrometallurgicalextractio（火法冶金）Hightemperatures（高温条件）underhighlyreducingconditionsusuallywithcarbon（还原反应）Fluxisusuallyincludedinasmeltingchargetoco

3、mbinewithgangue(脉石)oftheoretoformafusibleslag（溶剂，形成熔渣，杂质在熔渣中）.Thereducedmoltenmetalandamoltenslag(composedoftheunwantedgangueoxides)areproducedasseparatelayers（熔融金属和熔渣分层）2.Hydrometallurgicalextraction湿法冶金a)Comminutionofthestartingmaterialstoasuitableparticlesize.(破碎)b)Roastingto

4、convertthematerialsintoasolubleform,e.g.asulphatingroasttoconvertasulphideintosulphate.（煅烧，相转变过程）c)Leachingtodissolvethevaluablemetalinaleachliquor（浸取，选择性地溶解过程，有价值的金属溶解，其它不溶解）d)Separationoftheleachliquorfromtheunwantedmaterial（固—液分离）e)Recoveringthevaluablemetalfromtheleachliquor

5、.（富集，还原）3.ElectrometallurgicalExtractionElectrometallurgy（电冶金）involvestherecoveryofthemetalsatthecathodethroughtheelectrolysisordecompositionofeitheranaqueoussolutionorafusedsaltbythepassageofanelectriccurrent.冶金工艺特点：火法冶金成本低，生产率高，但污染大湿法冶金污染小，有色金属和稀有金属冶金电冶金生产率低，但金属纯度高4.Extraction

6、ofIron炼铁铁矿石ironores，gangueisrichinsilicaSiO2orrichinlimeCaO,phosphorus.熔剂Commonsmeltingfluxes（如何选择？）耐火材料，用于砌筑高炉、炼钢炉等炉村的材料燃料（焦炭）一、炼铁原料FluxChemicalnatureSilicaSiO2AcidLimeCaOBasicIronoxideFeOBasicFluorsparCaF2NeutralTable2.1Classificationofironores铁矿石脉石和硫磷杂质铁化合物Fe3O4(磁铁矿)Fe2O3(赤铁矿

7、)2Fe2O3·3H2O(褐铁矿)FeCO3(菱铁矿)65%50%30-50%30%二、高炉生产三、化学反应(1)燃料的燃烧C+O2→CO2温度达到1800℃(放热)CO2+C→CO1000℃(吸热)，热源和还原剂(3)熔剂反应CaCO3700℃－1000℃CaO+CO2(g)SlagCaO40%Al2O3,15%SiO2,3.5%，FeO,MnO.FeS(iniron)+CaO→CaS(inslag)+FeO(2)   Fe的还原FeO+CO→Fe+CO2FeO+C→Fe+CO铁的还原过程和去除脉石的造渣过程四、高炉产品（1）生铁炼钢生铁：作为平炉、

8、转炉热装炼钢的原料铸造生铁：用于铸件生产特殊生铁：如锰铁。硅铁，用作炼钢脱氧剂（2）高炉煤气：