Roasting pretreatment of high-sulphur bauxite and digestion performance of roasted ore.

High-S bauxite was pretreated in muffle, rotary tube and fluidised bed furnaces and the effects of roasting temperature and time on desulphurisation and digestion rate were studied. The results showed that elemental S was removed in the gas phase and that the S content of the roasted ore met the relevant industry standard. Optimum conditions for roasting pretreatment using the muffle or rotary tube furnaces were 750 degrees C for 30 min, for the fluidised bed furnace 800 degrees C for 10 min. The roasted ore produced using the fluidised bed exhibited the best digestion performance, with a digestion rate of 93.7% being achieved at 220 degrees C, a molar ratio of 1.3 and caustic soda concentration of 220 g/l.
High-S bauxite was pretreated in muffle, rotary tube and fluidised bed furnaces and the effects of roasting temperature and time on desulphurisation and digestion rate were studied. The results showed that elemental S was removed in the gas phase and that the S content of the roasted ore met the relevant industry standard. Optimum conditions for roasting pretreatment using the muffle or rotary tube furnaces were 750 degrees C for 30 min, for the fluidised bed furnace 800 degrees C for 10 min. The roasted ore produced using the fluidised bed exhibited the best digestion performance, with a digestion rate of 93.7% being achieved at 220 degrees C, a molar ratio of 1.3 and caustic soda concentration of 220 g/l.