Optimization of iron and aluminum recovery in bauxite

Abstract

Recovering iron and aluminum efficiently is the key route to utilize low-grade high-iron bauxite. Aiming to optimize the iron separating process and elevate both Fe and Al recovery ratio, three different Fe–Al recovery processes with different magnetic roasting (R), Bayer leaching process (L) and magnetic separation (S) orders were investigated. The studied processes include bauxite leaching → red mud roasting → magnetic separation (L–R–S), bauxite roasting → magnetic separation → leaching (R–S–L) and bauxite roasting → leaching → magnetic separation (R–L–S). The iron recovery ratio, Fe2O3 content in iron concentration and the bauxite dissolution ratio of each process were investigated. Moreover, the optimizations of the leaching, roasting and magnetic separation conditions were studied. Results indicate that the R–S–L process should be an advisable order to recover both alumina and iron. In the three processes, the R–S–L route had the highest alumina dissolution ratio and iron recovery ratio, which was 86.20% and 69.58%, respectively, while the Fe2O3 content of the iron concentrate was 40.66%.