Effect of chamosite on bayer process of special diasporic bauxite with high silica

Abstract

Technological investigations were carried out based on the Bayer process. Predesilication characteristic of the bauxite, the effects of digestion temperature and retention time, concentration of Na2O and amount of CaO addition on Al2O3 digestion efficiency in Bayer process, the settling characteristics of the red mud were determined. The bauxite in the northern region of China is diasporic type with high silica (in 6-15% SiO2). The main silica minerals in the bauxite are kaolinite and chamosite. The presence of high silica causes high bound-soda losses in the red mud in the Bayer process, but a part of silica content in the bauxite was in the form of chamosite, the bound-soda losses can be greatly reduced with chamosite mineral by using Bayer process. Therefore, it is necessary to study digestion characteristics of the special diasporic bauxite and settling separation properties of the red mud by Bayer process.