A CURRENT REVIEW ON BENEFICIATION PROCESS OF BAUXITE ORES FOR PRE-DESILICATION

Today, nearly all commercial production of alumina is obtained from standard Bayer process using bauxite ores as a raw material. One of the most important criteria for metallurgical-grade bauxites that can be directly fed to the Bayer process is the total silica content of bauxite. Because, reactive silica which tends to dissolve during bauxite leaching causes excessive caustic soda consumption and alumina losses in the Bayer process. For this reason, the reactive silica content in bauxite plays a critical role in the viability and economics of the Bayer process. Removing reactive silica from bauxite prior to leaching (also known as pre-desilication) is a major focus of effort for most alumina production plants. In recent years, it has been known that beneficiation methods such as froth flotation have been tried to pre-desilication. In this study, the major problems caused by reactive silica in bauxite ore and several beneficiation methods used for pre-desilication have been reviewed from the current literature. Among these methods, it has been determined that froth flotation is more important in terms of silica removal performance and industrial practice, and so investigations on bauxite flotation have been discussed extensively