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中南大学本科生毕业设计说明书摘要i摘要本设计的任务是设计年产量为80万吨的氧化铝厂。通过对国内外各种氧化铝生产工艺进行广泛深入的分析和对比，并根据本设计的具体条件，确立了本设计的工艺流程（拜耳法生产氧化铝）。经过论证，确定了生产的工艺参数：分解溶液的配料比αk为1.45，精液碱浓度为158.66g/l；母液αk为3.0，溶出碱浓度为240g/L；溶出温度260℃，溶出赤泥A/S=1.40，N/S=0.3，赤泥分离底流L/S=1.5，赤泥洗涤底流L/S=1.0。在以上参数的基础上确立了本设计的工艺流程：管道化—压煮器溶出→两次深锥赤泥沉降分离、四次深锥赤泥洗涤→二段晶种分解→流态化闪速焙烧→母液蒸发。其中，本次设计的重点是赤泥洗涤车间。通过计算分析，设计了四次反向洗涤的工艺流程，并对热损失进行了验算。同时，还对全厂生产成本进行了计算，对沉降车间的工作人员进行分配。最后，针对氧化铝生产会产生的主要环境污染，制定了具体的处理措施。关键字：氧化铝；拜尔法；赤泥；沉降中南大学本科生毕业设计任务书AbstractiiAbstractThetaskistodesignanoutputof800thousandtonsofaluminarefinery.Basedonextensiveanalysisoftheinternationalanddomesticaluminaproductiontechnologyandthespecificrequirementsofthedesign,theproductionprocess(Bayerprocess)isestablished.Theparametersofproductionprocessareobtainedasfallowed:theαk,Nkofpregnantliquoris1.45and158.66g/l,respectively;theαk,Nkofspentliquoris3.0and240g/l,respectively;thedigestingtemperatureis260℃,theA/Sofredmudis1.40,andN/Sis0.3;theL/Sofsedimentationredmudis1.5,and1.0ofthewashingredmud.Onthebasisoftheaboveparameters,thetechnologyisestablishedasfallowes:tube-autoclavedigestion→twodeepconesettlingtankandfourdeepconesettlingtankredmudsedimentationandwashing→two-stageprecipitation→fluidizationflashcalcination→vaporizingspentliquor.Thekeynoteoftheseistodesigntheredmudwashingworkshop.Aprocesscontainingfour-timereversedwashingisdesigned.Moreover,itsheatlossiscalculated.Meanwhile,thecostoftheplantisalsocalculated,andthestaffoftheredmudwashingworkshophasbeenallocatedaswell.Finally,specificmeasuresareestablishedbecauseofthemainpollutionofthealuminaproduction.Keywords:alumina;Bayerprocess;redmud;sedimentation中南大学本科生毕业设计说明书目录I目录摘要...........................................................................................................................................IABSTRACT....................................................................................................................................II绪论........................................................................................................................................1第1章厂址和生产能力的选择与论证......................................................................................81.1厂址的选择与论证..............................................................................................................81.2生产能力的选择和论证....................................................................................................10第2章生产方法、工艺流程及主要技术、经济指标的选择与论证..................................122.1氧化铝生产方法现状........................................................................................................122.1.1拜尔法..........................................................................................................................122.1.2石灰石烧结法..............................................................................................................122.1.3拜尔-烧结联合法........................................................................................................132.1.4其他方法......................................................................................................................142.2生产方法的选择与论证....................................................................................................152.3工艺流程的选择与论证....................................................................................................162.3.1原料准备......................................................................................................................162.3.2预脱硅..........................................................................................................................172.3.3高压溶出......................................................................................................................172.3.4赤泥沉降分离及洗涤.................................................................................................202.3.5赤泥干法输送、堆存.................................................................................................282.3.6铝酸钠溶液控制过滤.................................................................................................292.3.7晶种分解......................................................................................................................302.3.8氢氧化铝过滤..............................................................................................................322.3.9氢氧化铝焙烧..............................................................................................................332.3.10母液蒸发....................................................................................................................362.3.11碳酸钠苛化................................................................................................................372.4主要技术、经济指标的选择与论证...............................................................................372.4.1溶出温度......................................................................................................................372.4.2配料αk................................................................................................................