Heat transfer system in iron and steel smelting

Process of Alumina Production

The basic principles of the Bayer process for alumina production are as follows:

(1) Use NaOH solution to dissolve out the bauxite and the alumina in the resulting sodium aluminate solution is separated out as aluminum hydroxide under the conditions of adding seeds or stirring continuously, that is, seed precipitation process.

(2) After decomposition, the mother liquor can be used to dissolve out new bauxite at high temperature after evaporation and concentration, that is, dissolution process.Using these two processes alternately, you can get a batch of aluminum hydroxide by processing each batch of ore, which constitutes the so-called Bayer process cycle.The reaction equation is as follows:

Al2O3（1or3）H2O＋2NaOH＋aq2NaAl(OH)4＋aq

Heat exchanger type

Bayer process of alumina production: to use NaOH solution to dissolve out the bauxite and the alumina in the resulting sodium aluminate solution is separated out as aluminum hydroxide under the conditions of adding seeds or stirring continuously The heat exchange equipment used in this process are as following:

Pre-heater: to heat up the raw pulp to 90 ℃, removing the silicon from the pulp.

Condenser: to cool down the raw pulp after high-pressure dissolution, for pulp dilution.

Plate heat exchanger: to heat the refined sodium aluminate solution, separated to obtain more mother liquor.

Evaporator: to evaporate and condense the mother liquor generated in the whole process, which can be used to dissolve out new bauxite at high temperature and achieve the cycle collection of mother liquor.