Optimization Of Process Design For Alumina Production Form Diaspore By Bayer Process

With the rapid development of China's aluminum industry,Bauxite reserves reduces sharply and the grade is getting worse.On the other hand,the increasing alumina production and long-term relative low market requirement will bring challenge to the profit and survivability of modern alumina refinery.So,optimize alumina produce process,reduce production consumption and cost,alleviate bad effect to the environment,make alulmina industry grow healthly will have high economic and social benefit.Based on current situation of alumina production from diaspore by Bayer process,study of four aspects are researched in this paper,includes optimization of produce index,decrease of energy consumption,application of large-scale machines and reasonable layout of general plan.Firstly,research the process index of digestion and precipitation based on bauxite test result,give new digestion conception of high temperature and low caustic concentration,which can decrease the molecular ratio of post-digestion liquor and green liquor.In addition,improve the temperature procedure of precipitation and this can also improve the process index.Secondly,recover low quality energy resource such as low temperature water,steam and liquor,which will reduce energy consumption of alumina.Thirdly,apply more large-scale machines to project,which can reduce refinery general area,staff,project investment and running cost.Last,according to the character of different process,produce flow and machine,optimize general layout,such as centralized arrangement of interrelated procedures and machines,adjust network layout and reduce buffered device.To improve alumina refinery design by implication of methods mentioned above,calculation of mass balance and rational machine selection.The contradistinctive results are listed between pre-optimization and after,the consumption of raw material and energy,project investment and running cost are all reduces after optimization.The bauxite consumption is reduced from 2335.25kg/t-Al2O3 to 2297kg/t-Al2O3,steam consumption is reduced from 2184kg/t-Al2O3 to 1855kg/t-Al2O3;process energy consumption is reduced from 9.76GJ/t-Al2O3 to 8.52 GJ/t-Al2O3,and the direct product cost is reduced by 40.52RMB/t-Al2O3.