摘要:本设计的任务是设计年产量为40万吨的氧化铝厂。通过对国内外各种氧化铝生产工艺进行了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。经过论证，确定了生产的工艺参数：分解溶液的苛性比αk为1.44，精液碱浓度为148g/l；母液αk为2.91，溶出碱浓度为200 g/l；溶出温度265℃，溶出赤泥A/S=1.2，N/S=0.5，赤泥分离底流L/S=2.30，赤泥洗涤底流L/S=1.80。在以上参数的基础上确立了本设计的工艺流程：管道—停留罐溶出→三次深锥赤泥沉降分离、五次深锥赤泥洗涤→二段晶种分解→流态化闪速焙烧→母液蒸发。其中，本设计的重点是赤泥洗涤车间。通过计算得出在本设计中使用3个直径为24米，高度为15米的分离槽，5个直径为25米，高度为15米的洗涤槽,设计了五次反向洗涤的工艺流程，进行了热损失的验算。

关键词：氧化铝生产；拜耳法；三水铝石；溶出

ABSTRACT:The task is to design an output of 400 thousand tons of alumina refinery. Based on extensive analysis of the international and domestic alumina production technology, and the specific requirements of the design, the production process is established. With demonstrating，the parameters of production process are obtained: the αk ,Nk of pregnant liquor is 1.44 and 148 g/l，respectively; the αk  ,Nk of spent liquor is 2.91 and 200g/l， respectively; the digesting temperature is 265℃，the A/S of red mud is 1.2，and N/S is 0.5，the L/S of sedimentation red mud is 2.30,and 1.80 of the washing red mud. On the basis of the above parameters, the technology is established as fallows :tube-autoclave digestion →three deep cone settling tank and five deep cone settling tank red mud sedimentation and washing →two-stage precipitation →fluidization flash calcination → vaporizing spent liquor. the keynote of these is the design of the red mud washing workshop. A process containing six-time reversed washing is designed. Moreover, it is heat loss is calculated. Meanwhile ,specific measures are established because of the pollution of the alumina production process.    

Keywords:Alumina production;  Bayer process;  Gibbsite；Leaching