Effect of Thermal Activation Temperature on Pre-desilication of Low-Grade Bauxite

Abstract

With the increase of requirements for environmental protection, the sintering process with high carbon dioxide emission was gradually reduced in the application. However, for low-grade bauxite, it was difficult to be directly economically utilized by the Bayer process, and a pre-desilication process was often required. This paper researched the influence of different thermal activation temperatures on the pre-desilication process of low-grade bauxite. The results showed that the phase transformation of low-grade bauxite was not much different at different thermal activation temperatures, but the pre-desilication behavior was different. Compared with 650 and 700 °C, the pre-desilication results of low-grade bauxite after thermal activation at 600 °C had a significant improvement. Only after 30 min of leaching, the ratio of alumina to silica of low-grade bauxite can be increased from 2.39 to 6.78. This study may have a certain significance for selecting a suitable thermal activation temperature to promote the high-efficiency pre-desilication of low-grade bauxite.