Beneficiation of Aluminum-, Iron-, and Titanium-Bearing Constituents from Diasporic Bauxite Ores

Abstract

In this study, extraction of aluminum-, iron-, and titanium-bearing constituents from diaspore-type bauxite ores was investigated by stepwise treatment consisting of pre-desilication via alkali-leaching of bauxite ore, extraction of alumina via Bayer process, and recovery of iron from red mud via magnetic separation. The pre-desilication results showed that the removal of silica reached 73.92% and that the mass ratio of alumina to silica (A/S) of bauxite concentrate increased from 2.92 to 9.25 under the conditions of sodium hydroxide concentration of 50 wt.%, leaching temperature of 95°C, leaching time of 30 min, and liquid-to-solid ratio of 5 mL/g. A total of 96.31% alumina was extracted from the bauxite concentrate via the Bayer process. Subsequently, by using two-step magnetic separation (intensity: 0.8 T and 0.2 T), TiO2-bearing iron concentrate with total iron grade of 56.39% and TiO2 grade of 8.66% was obtained with recoveries of iron and TiO2 of 55.79% and 17.37%, respectively. The grade of TiO2 reached 21.22% in the nonmagnetic fraction.