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 TiO 2 , SiO 2 etc.
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 AlCl 3 , and separating said precipitate from said liquid; and heating said precipitate under conditions effective for converting AlCl 3 into Al 2 O 3 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 is provided a method for extracting aluminum ions from aluminous ores, such as argillite. The process comprises leaching the argillite with an acid such as HCI so as to obtain a composition comprising the aluminum ions and iron ions; at least partially removing the iron ions from the composition by substantially selectively precipitating the iron at a pH of about 3 to about 6 by adding a base and at least partially removing the precipitated iron ions so as to obtain an Al-rich composition; and optionally purifying the Al-rich composition by adding a base for substantially selectively selectively precipitating the aluminum ions, by means of a hollow fiber membrane, or by a liquid-liquid extraction.
Abstract:
There are provided methods for preparing hematite. For example, the method can comprise reacting a basic aqueous composition comprising the iron and the aluminum with hematite under conditions suitable for at least partially converting the iron into hematite under the form of a precipitate, thereby obtaining a liquid phase and a solid phase; and separating the liquid phase from the solid phase.
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 methods for separating iron ions from aluminum ions contained in an acidic composition. The methods comprise reacting the acidic composition with a basic aqueous composition having a pH of at least 10.5 so as to obtain a precipitation composition, maintaining the precipitation composition at a pH above 10.5 so as to cause precipitation of the iron ions, at least substantially preventing precipitation of the aluminum ions, and to obtain a mixture comprising a liquid portion and a solid portion; and separating the liquid portion from the solid portion. There are also provided methods for treating an acidic composition comprising iron ions and aluminum ions. Such methods can be useful for preparing products such as alumina, aluminum, hematite etc.
Abstract:
The present disclosure relates to processes for recovering rare earth elements from an aluminum-bearing material. The processes can comprise leaching the aluminum-bearing material with an acid so as to obtain a leachate comprising at least one aluminum ion, at least one iron ion, 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 aluminum ion and the at least one iron 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.