Abstract:Roasting desulfurization and digestion performance of high sulfur-bearing bauxite of millstone-milling (particle size of 75% -830 μm) and ball-milling (particle size of 85% -75 μm) were investigated comparatively with raw ore. The results show that sulfur content of millstone-milling and ball-milling drops from 2.33% to 0.68% and 0.64% respectively after roasted at 700 ℃ for 30 min, which meets the requirement of alumina production. Al2O3 digestion rate of roasted sample can be improved by 3~4.5 percentage under the optimum digestion conditions including caustic alkali concentration of 245 g/L, digestion temperature of 260 ℃, lime dosage of 8%, and digestion time of 60 min.