Effect of different silica mineral compositions on the digestion results in bayer process

Abstract

The bauxite in the northern region of China belongs to diasporic type ore with high silica. The main silica minerals in the bauxite is kaolinite, illite and chamosite. Technological investigations were carried out based on the Bayer process. The presence of high silica causes high bound-soda losses in the red mud and the decrease of leaching rate. The dissolution behavior of different silicate minerals has obvious effect on the digestion of bauxite. Predesilication characteristic of the bauxite, the effects of dissolution temperature and retention time on A1203 digestion efficiency were determined. Experiment results showed that of chamosite and illite mineral characteristics and dissolution characteristics of chamosite helped to lower alkali consumption to improve the digestion rate of bauxite.