Influence of the process conditions on agglomeration during the seeded precipitation of sodium aluminate solution

Agglomeration of gibbsite crystals is an important stage in the Bayer process. In the present study, the effect of the crystallization temperature, seed mass, stirring rate, caustic concentration of liquor, molecular rate on agglomeration were investigated. It appeared that at the temperature of 78 degrees C, the particle size enlarges significantly. Low caustic concentration is highly advantageous for the agglomeration. There is an optimum seed mass, which is 60gl(-1) for the gibbsite agglomeration in a batch crystallizer, in our experiments. In order to get coarser gibbsite, a proper stirring rate should be chosen. And interpretation of the results was proposed.