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A REVIEW OF THE BAUXITE RESIDUE SINTER-LEACH PROCESS

Qi, T. Hodge, H. Hawker, W. Hayes, P. Vaughan, J.

Annually, in excess of 150 million tonnes of bauxite residue are produced as a by-product of the Bayer process. The current industry standard for treating this material is to maintain it in long-terms storage facilities. This represents a significant operating cost, as well as being a safety and environmental risk. Caustic sodium hydroxide reagent and alumina product are lost to the residue in the form of desilication products produced during the Bayer process. As reactive silica levels in bauxite ore increase, the amount of caustic and alumina being lost to the residue is becoming a serious cost. To deal with all of these issues, a process must be implemented to reduce the cost and risk of bauxite residue.

The bauxite residue sinter-leach process is capable of delivering all of these benefits. This paper presents a critical review of current literature on this process, with an emphasis on recent research from China. The chemical fundamentals of both the sintering and leaching are explored. The major processing issues and implementation hurdles are discussed. Finally, examples of industrial application are presented along with opportunities for future development of the process.