以含铁海砂为原料的含碳球团直接还原研究

以含铁海砂为原料的含碳球团直接还原研究重庆大学硕士学位论文学生姓名：沈维华指导教师：朱子宗教授专业：冶金工程学科门类：工学重庆大学材料科学与工程学院二O一O年五月TheResearchonDirectReductionProcessforCarbon-containingPelletsofSeaSandIronOreAThesisSubmittedtoChongqingUniversityinPartialFulfillmentoftheRequirementfortheDegreeofMasterofEngineeringByShenWeihuaSupervisedbyProf.ZhuzizongMajor:MetallurgyEngineeringCollegeofMaterialsScienceandEngineeringofChongqingUniversity,Chongqing,ChinaMay,2010重庆大学硕士学位论文中文摘要I摘要随着钢铁行业的发展，富矿资源日益枯竭，而铁矿资源需求量却日益增加，从而导致铁矿价格不断飙升，钢铁企业面临着巨大的经济压力。产自新西兰近海滩的海砂资源储量丰富，价格低廉，来源也较稳定，但是由于其钒钛含量较高，粒度较粗，结构致密，硬度、熔点较高等原因，还未能大规模的应用于钢铁生产。本文旨在对海砂造含碳球团并直接还原进行实验室基础研究，探索海砂直接还原的特点、规律，得出了海砂造含碳球团以及直接还原的最佳工艺参数，并在此基础上提出了综合利用海砂资源的工艺流程方案，为大规模开发利用这类铁矿砂提供依据。针对海砂成球性差难以造球的物化特性，采取了球磨预处理和选用合理粘接剂的两项措施来改善海砂所造球团的质量。球磨预处理实验得出海砂最佳球磨预处理时间为60分钟，再增加球磨时间，球磨效率将大幅下降。造球实验得出最优造球工艺参数，即采用（水玻璃+钠基优质膨润土）复合粘接剂，其配加量为4.0%+1.0%，海砂原料粒度组成为（-300目=30%，300目~200目=40%，+200目=30%）。在该条件下所造球团能够满足竖炉与固定床对球团的性能要求。在含碳球团的直接还原中，以最佳造球工艺参数所造的球团为原料，采用单因素实验与正交设计实验来考察还原温度、配碳量、还原时间对含碳球团直接还原的影响。而不考虑还原气氛对还原的影响，这是由于含碳球团的还原是依靠自身煤粉还原的自还原反应，其还原速度主要是由自还原速度决定的，其在还原过程中能够抑制外在气氛对球团还原的影响。通过实验研究得出了影响含碳球团直接还原指标的因素依次为：C/O摩尔比还原温度还原时间，并确定出了最优还原参数，即温度控制在1300℃，C/O摩尔比控制在1.2，还原时间为30min。该条件下直接还原铁金属化率达到94.01%。在对实验生产的直接还原铁的扫描电镜和矿相分析中发现：温度达到1300℃时，球团中铁相发生聚集，形成大片的铁连晶，与脉石分离效果良好，并且钛铁也发生显著分离现象，低于这个温度时，铁相呈斑点状分布，未形成大面积铁连晶，钛元素仍较大程度的嵌布在铁元素中，球团中的钛元素大部分已经还原为TiC、TiN。最后，在实验室实验研究的基础上，提出了海砂造含碳球团→直接还原→磁选分离铁粉和高钒钛脉石，综合合理利用海砂资源的工艺流程方案。关键词：海砂，钒钛铁矿砂，含碳球团，直接还原重庆大学硕士学位论文英文摘要IIABSTRACTWithdevelopmentoftheironandsteelindustry,richoreresourcesaredepleted,andthedemandofironorehasincreasedmoreandmore,resultinginsoaringtheironoreprice.Steelcompaniesarefacinghugefinancialpressure.SeasandironoreisfromthebeachofNewZealandwhichisresource-richandlowcost,sourcesaremorestable,butduetoitshighcontentofvanadiumandtitanium,coarsegrainsize,compactstructure,hardness,highmeltingpointandotherreasons,ithasnotbeenlargelyusedinsteelmaking.Thisarticleaimstoresearchproducingcarbon-containingpelletswithseasandironorebydirectreductiontoexplorethecharacteristicsofdirectreductionofseasandironore,togettheoptimumparametersofseasandironoreinmakingthecarbon-containingpelletsanditsdirectreduction,andtoputforwardaprogramofcomprehensiveutilizationofseasandironoreresourcetoprovidethebasistheoryoflargelyuseofsuchironore.Forbadballingofseasandironore,takingtwomeasuresofball-millingpretreatedandreasonableadhesivetoimprovethequalityofpelletswhichmadeofseasandironore.Drawnintheball-millingpretreatment:thebestball-millingpretreatmenttimeofseasandironoreis60minutes,ball-millingefficiencywilldeclineifyouincreasetheball-millingtime.Intheexperimentofpalletizing,obtainingtheoptimalparametersforpelletizing,usedcompositebinder(waterglassbinderandhigh-qualitysodiumbentonitebinder),thereasonableratiois4.0%ofwaterglassbinderand1.0%ofhigh-qualitysodiumbentonitebinder,sandgrainsizecompositionofrawmaterials(-300mesh=30%,300mesh~200mesh=40%,+200mesh=30%).Underthecondition,carbon-containingpelletsmeetperformancerequirementsofthefixedbedandshaftfurnace.Inthedirectreductionofcarbon-containingpellets,thepelletsofthebestpalletizingparameterswasmadefortherawmaterial,singlefactorexperimentsandorthogonaldesignexperimentswereusedtostudytheInfluenceofreductiontemperature,carboncontent,reducingtimetodirectpelletsreductionwithouttakingtheimpactofreducingatmosphereonthereductionintoaccount,thisisduetothereductionofcarbon-containingpelletsisthereductionofcoaldependonreductionreactionitself,thereductionrateofcarbon-containingpelletsismainlydeterminedbythespeeditsownreductionreaction,itcansuppresstheimpactoftheexternalatmosphere.The重庆大学硕士学位论文英文摘要IIIexperimentprovesthattheimpactfactorsInproperorderofdirectreductionpellets:C/Omolarratioreductiontemperaturereductiontime,andfixtheoptimalreductionofparametersthattemperatureiscontrolledat1300℃,C/Omolarratiois1.2,reductiontimeis30min.Undertheseconditions,ironmetallizationrateindirectreductionreaches94.01%.directreductionironofexperimentalproductionisanalyzedbymeansofthescanningelectronmicroscopeandmineralogicalanalysis,theresultsshowthat:whenthetemperaturereaches1300℃,ironinpelletsstartstoaggregate,formalargeareaofironjoinedcrystal,andseparateironfromgangueiseasy,andsignificantseparationoftitanium-ironalsooccurs,belowthistemperature,theironshowapatchydistribution,evenwithoutformingalargeareaofironjoinedcrystal,titaniumelementisstilllargeextentembeddedintheiron,themajorityoftitaniuminpelletshavebeenreducedtoTiC,TiN.Finally,arationalandintegratedprocessplanbasedonexperimentalresearchinthelaboratorywasproposed：makingcarbon-containingpellets→directreduction→Magneticseparationofironpowderandganguewhichcontainhighvanadiumandtitanium.Keywords：seasandironore,vanadiferous,carbon-containingpellets,directreduction重庆大学硕士学位论文目录IV目录中文摘要..........................................................................................................................................I英文摘要........................................................................................................................................II1绪论.............