Roasting Pretreatment of High-sulfur Bauxite

Roasting pretreatment of high sulfur bauxite was studied using a rotary kiln, and the effects of roasting temperature and roasting time on sulfur content and digestion performance of high sulfur bauxite were examined. Changes of microscopic appearance and crystal structure were analyzed with SEM and XRD techniques. The mechanism of desulphurization and roasting pretreatment was also studied. The experimental results indicate that the sulfur in bauxite was successfully discharged as gas form through roasting, the sulfur content of high sulfur bauxite met the industrial standard under the conditions of 750 ℃ roasting temperature and 60 min holding time. The digestion rate of alumina was above 97% under the conditions of 220 ℃ digestion temperature and 60 min holding time.