Extracting Al2O3 and TiO2 from Red Mud Smelting Separation Slag by Alkali and Acid Leaching Methods

Recovery of valuable metals from red mud smelting separation slag is important for environmental protection and saving natural resources. In this paper, we propose a recycling process by mineral phase reconstruction conducted under an air atmosphere. process, NaOH Ca(OH)2 roasting Al2O3 NaAlSiO4 was performed, SiO2 were converted into alkaline-soluble NaAlO2 Ca2SiO4, respectively. the consequent steps, more than 80% selectively dissolved leaching solution using 95 °C, obtained can be used as source extracting alumina. Then, 20 wt.% HCl to remove residue, obtaining SiO2-containing concentrated residue undissolved TiO2 CaO. Finally, enable higher metal rate, study provides novel, clean, sustainable method slag.