Method of producing anhydrous aluminum chloride from acid leach-derived ACH and the production of aluminum therefrom
AssigneeAtlantic Richfield Company
InventorsRaouf O. Loutfy, James C. Withers
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Abstract
An improved process is provided for producing via ACH anhydrous aluminum chloride suitable for electrolytic reduction to aluminum wherein the feed ACH is acid leach derived. In a preferred embodiment the acid leach derived ACH is single stage crystallized.
Claims10
A method of producing aluminum by electrolytically reducing anhydrous aluminum chloride from iron and phosphorous or magnesium-containing aluminum hexahydrate crystals comprising:
- (a) leaching aluminous raw material containing phosphorous or magnesium with a hydrochloric acid leach liquor to dissolve the alumina fraction into soluble aluminum chloride;
- (b) separating said leach liquor from any solids present;
- (c) removing all soluble iron chloride from said liquor to obtain a substantially iron free, aluminum hloride-containing pregnant liquor;
- (d) crystallizing said pregnant liquor to produce a separable slurry of phosphorous or magnesium-containing aluminum hexahydrate (ACH) crystals;
- (e) heating said phosphorous or magnesium-containing ACH crystals from said slurry to a temperature of about 200.degree. C. to 450.degree. C. to produce partially calcined ACH (PCACH);
- (f) chlorinating said PCACH in the presence of chlorine and a reductant to produce said anhydrous aluminum chloride;
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- (g) electrolytically reducing said anhydrous aluminum chloride to produce aluminum and chlorine.
In a method of producing aluminum by electrolytic reduction of anhydrous aluminum chloride obtained from aluminum chloride hexahydrate (ACH) by a process comprising heating said ACH to a temperature of about 200.degree. to about 450.degree. C. thereafter reductively chlorinating in the presence of a gaseous mixture of chlorine and one or more gaseous reductants, the improvement comprising forming said anhydrous aluminum chloride from ACH obtained by a method comprising:
- (a) leaching aluminous raw material containing iron and phosphorous or magnesium with a hydrochloric acid leach liquor to dissolve the alumina fraction into soluble aluminum chloride;
- (b) separating said leach liquor from any solids present;
- (c) removing any soluble iron chloride present from said liquor by solvent extraction to obtain a substantially iron-free pregnant liquor;
- (d) crystallizing said pregnant liquor to produce a separable slurry of phosphorous or magnesium-containing aluminum chloride hexahydrate (ACH) crystals.
Dependencies are inferred from the claim text.