Abstract: There is provided a process for purifying aluminum ions comprising: reacting an aluminum-containing material with an acid so as to obtain a composition comprising aluminum ions; precipitating said aluminum ions in the form of AlCl3; optionally converting AlCl3 into Al(OH)3; and heating said AlCl3 or said Al(OH)3 under conditions effective for converting AlCl3 or Al(OH)3 into Al2O3 and optionally recovering gaseous HCl so-produced. Aluminum ions so purified are thus useful for preparing various types of alumina.

Abstract: There are provided processes for converting alumina into ?-Al2O3 or transition alumina that comprise heating the alumina at a temperature of about 900° C. to about 1200° C. in the presence of steam and optionally at least one gas under conditions suitable to obtain the ?-Al2O3 or transition alumina. For example, the alumina can comprise a transition alumina (such as ?-Al2O3), an amorphous alumina or a mixture thereof.

Abstract: There are provided processes for purifying aluminum ions. Such processes comprise precipitating the aluminum ions under the form of Al(OH)3 at a first pH range; converting Al(OH)3 into AlCl3 by reacting Al(OH)3 with HCl and precipitating said AlCl3; and heating the AlCl3 under conditions effective for converting AlCl3 into Al2O3 and optionally recovering gaseous HCl so-produced. The processes can also comprise converting alumina into aluminum.

Abstract: There is provided a process for preparing alumina. The process comprise leaching an aluminum-containing material (for example an industrial waste product chosen from red mud, fly ashes and a mixture thereof), with HCl so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate. Then, the process comprises reacting the leachate with HCl so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlCl3, and separating the precipitate from the liquid. Then, the precipitate is reacted with a base. Finally, the process comprises heating the precipitate under conditions effective for converting the precipitate into Al2O3.

Abstract: There are provided processes for purifying aluminum ions. Such processes comprise precipitating the aluminum ions under the form of Al(OH)3 at a first pH range; converting Al(OH)3 into AlCl3 by reacting Al(OH)3 with HCl and precipitating said AlCl3; and heating the AlCl3 under conditions effective for converting AlCl3 into Al2O3 and optionally recovering gaseous HCl so-produced. The processes can also comprise converting alumina into aluminum.