Research On Strengthening Technology Of Evaporation Efficiency In Bayer Process

Bayer process is the most popular alumina production process at home and abroad nowadays, and the evaporation procedure is the main process in the production. The consumption of evaporation procedure accounts for 20%-25% in the whole Alumina production process. It is one of the key technical issues in alumina production to increase the evaporation productivity and reduce the steam consumption in the evaporation procedure.On the basis of documentary analysis and engineering practices, the technologies and the equipments of the evaporation process which is used to resolve mother liquor are systematical analysis, according to problems about the new evaporation pan used after the factory project extended and technology updated, such as not reaching standard and production target, low productivity, and high steam consumption etc. The key factors to impact on the evaporation productivity and the consumption are studied, some effective measures are taken to reach the standard, aiming at promoting the evaporation efficiency.Improving the technology of evaporation process for alumina production is studied and discussed in the article. Through the heat balance calculation and the actual production analysis,the main factors affecting the efficiency of evaporation are determined:fast scaling in the evaporation pan;parts of technological processes needed to be optimized; the operation life and normal production affected by the evaporation acid scouring; the evaporation efficiency affected by changes of material; plenty of heat carried away by condensate etc.Based on investigation and demonstration the evaporation efficiency can be promoted by the following measures:to slow down the scaling by using the new scale inhibitor;to optimize depletion processes and to remake circulating water underground processes;to use the new type inhibitors by contrast test;to fully exert evaporation efficiency by flash evaporation technology;to to fully utilize exhaust steam by adding horizontal shearing drainer.It is found on research that after taking series of measures to promote resolving mother liquor evaporation efficiency in Bayer process,the goal to promote yield and reduce consumption are achieved, the standard can be reached and production efficiency is promoted as well. Meanwhile, the further research of strengthening evaporation efficiency has great economic benefits and social benefits. It can be popularized and applied widely in the same industry.