Experimental Study of Solid Dispersion in a Seeded Precipitation Tank with Slight Agitation for Gibbsite Crystallization

In order to explore the energy saving measures in gibbsite crystallization process for alumina production by Bayer method, industrial experiment was carried out to investigate the solid dispersion in a slight agitation seed precipitation tank for gibbsite crystallization. The experimental results showed that little difference of solid concentration, only 48.19 g·l-1is found in the range from 5 meters depth to the tank bottom, which is the most zone of the tank, and there is a somewhat large difference in the top 5 meters zone near the surface that is about 149.66 g·l-1. Therefore, under the condition of slight agitation, solid content would not concentrate to the tank bottom completely with the normal work flow. It is suggested that the work of production would not be interrupted in less agitation than before, and the electrical energy saving rate is about 34%. The effects of reduced agitation on the yield and the quality of gibbsite crystallization should be studied carefully in subsequent works.