A new route for separation and recovery of Fe, Al and Ti from red mud

Red mud is one kind of by-products rejected from industrial production of alumina plant and characterized by high content of alkaline and containing many valuable metals such as iron, aluminum, titanium, etc. It is urgent to effectively utilize red mud for the sustainable development of aluminum metallurgy industry. In this paper, a new route was proposed to fully recover Fe, Al2O3 and TiO2 from the red mud, which includes three procedures, i.e. pre-reducing-smelting, alkaline leaching and acid leaching. The pre-reducing-smelting step was employed to recover iron from the mud, producing pig iron at an iron recovery of some 98.15% and slag containing 43.17% Al2O3 and 15.71%TiO2, respectively. Then, based on the thermal dynamic calculations, a modification of the slag-alkaline leaching and hydrochloric acid leaching process were conducted to obtain the stepwise recovery of Al2O3 and TiO2, respectively, from the smelting slag. Aluminum and titanium were recovered in the form of sodium aluminum solution and perovskite at a recovery of 85.85% and 95.53%, respectively. The innovative route is probably a potential way to achieve comprehensive and clean utilization of red mud.