Abstract: The present disclosure relates to processes for recovering rare earth elements from various materials. The processes can comprise leaching the at least one material with at least one acid so as to obtain a leachate comprising at least one metal ion and at least one rare earth element, and a solid, and separating the leachate from the solid. The processes can also comprise substantially selectively removing at least one of the at least one metal ion from the leachate and optionally obtaining a precipitate. The processes can also comprise substantially selectively removing the at least one rare earth element from the leachate and/or the precipitate.

Abstract: There are provided processes for preparing alumina. These processes can comprise leaching an aluminum-containing material with HCl so as to obtain a leachate comprising aluminum ions and a solid, and separating said solid from said leachate; reacting said leachate with HCl so as to obtain a liquid and a precipitate comprising said aluminum ions in the form of AlCl3, and separating said precipitate from said liquid; and heating said precipitate under conditions effective for converting AlCl3 into Al2O3 and optionally recovering gaseous HCl so-produced. These processes can also be used for preparing various other products such as hematite, MgO, silica and oxides of various metals, sulphates and chlorides of various metals, as well as rare earth elements, rare metals and aluminum.

Abstract: There are provided processes for treating red mud. For example, the processes can comprise leaching red mud with HCl so as to obtain a leachate comprising ions of a first metal (for example aluminum) and a solid, and separating said solid from said leachate. Several other metals can be extracted from the leachate (Fe, Ni, Co, Mg, rare earth elements, rare metals, etc.). Various other components can be extracted from solid such as TiO2, SiO2 etc.