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.

IPC Classes  ?

• C22B 3/10 - Hydrochloric acid
• C01F 7/02 - Aluminium oxideAluminium hydroxideAluminates
• C01F 7/56 - Chlorides
• C22B 3/42 - Treatment or purification of solutions, e.g. obtained by leaching by ion-exchange extraction
• C22B 3/46 - Treatment or purification of solutions, e.g. obtained by leaching by chemical processes by substitution, e.g. by cementation
• C22B 21/00 - Obtaining aluminium

Abstract

There are provided processes for converting alumina into α-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 α-Al2O3 or transition alumina. For example, the alumina can comprise a transition alumina (such as γ -Al2O3), an amorphous alumina or a mixture thereof.

IPC Classes  ?

• C07F 7/30 - Germanium compounds
• C01F 7/02 - Aluminium oxideAluminium hydroxideAluminates

Abstract

There are provided processes for decomposing AlCl3•6H2O into γ-Al2O3 that comprise heating the AlCl3•6H2O at a temperature of about 600°C to about 800°C in the presence of steam and optionally at least one gas (for example chosen from air, argon, nitrogen, carbon dioxide, hydrogen and hydrochloric acid), under conditions suitable to obtain the γ-Al2O3. For example, the γ-Al2O3 obtained can be suitable for use in an aluminum smelting process or optionally for processes for treating the γ-Al2O3 to obtain high purity alumina, fused alumina, transition alumina, tabular alumina, calcined alumina, ultra-pure alumina or specialty alumina.

IPC Classes  ?

• C01F 7/30 - Preparation of aluminium oxide or hydroxide by thermal decomposition or by hydrolysis or oxidation of aluminium compounds
• C01F 7/02 - Aluminium oxideAluminium hydroxideAluminates
• C22B 3/10 - Hydrochloric acid

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.

IPC Classes  ?

• C01F 7/02 - Aluminium oxideAluminium hydroxideAluminates
• C01F 7/30 - Preparation of aluminium oxide or hydroxide by thermal decomposition or by hydrolysis or oxidation of aluminium compounds
• C01F 7/34 - Preparation of aluminium hydroxide by precipitation from solutions containing aluminium salts
• C22B 21/04 - Obtaining aluminium with alkali metals
• C22B 3/10 - Hydrochloric acid
• C22B 3/46 - Treatment or purification of solutions, e.g. obtained by leaching by chemical processes by substitution, e.g. by cementation
• C25C 3/06 - Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium