Processing Diasporic Red Mud by the Calcification-Carbonation Method

The novel calcification-carbonation method was proposed to process the diasporic red mud discharged from Bayer process alumina plant. In this study, Batch experiments were performed to evaluate the potential effects of important parameters such as temperature, amount of CaO added, CO2 partial pressure and carbonation cycles on the recovery of alkali and alumina. The results showed that 78.74% alumina was recovered from the diasporic red mud with decreases in the mass ratios of Al2O3 to SiO2 (A/S) from 1.27 to 0.27. The Na2O content in the processed red mud was less than 0.3 wt%, and it can be used as a construction material.