Processing of Demetallized Cast Iron Slag to Obtain REEs Concentrates and Titanium Dioxide

Under conditions of depletion of natural resources and increasing volumes of techno-genic waste from metallurgical and alumina production, the development of technologies for the integrated processing of sludges with the extraction of valuable components becomes highly relevant. This study proposes a method for the combined processing of red mud and dump sludge to obtain pig iron, a rare earth element concentrate, and titanium dioxide. The reduction smelting of a briquetted charge composed of sludge mixtures was carried out in a muffle furnace at 1350–1400 °C with the addition of a reducing agent. Magnetic separation of cast iron slag made it possible to reduce the iron content in the non-magnetic fraction and increase the concentration of REEs. As a result of nitric acid leaching of the non-magnetic slag fraction, followed by neutralization and calcination of the titanium-containing precipitate, a rare earth element concentrate and titanium dioxide containing 96.5% TiO2 were obtained. The developed method ensures the utilization of technogenic raw materials and contributes to the creation of an additional resource base for the production of strategically important materials.