Coproducing alumina, iron oxide, and titanium-dioxide from aluminum ore bodies and feedstocks

Abstract

A process for the extraction of alumina, iron oxide and titanium dioxide from bauxite ore and clays, and other ore bodies and feedstocks. The process starts by sulfuric acid leaching of the feedstocks in pressure autoclaves at about 200° C. and appropriate pressure. A leach liquor of sulfate salts of aluminum, iron and titanium is obtained. Any iron values are converted to a ferrous state. A recycled potassium sulfate helps produce double aluminum alkali sulfate crystals in the reduced leach liquor. The crystals are removed at about 20°-60° C. with the help of SO2 gases that reduce the ferric. Such double salt is hydrolyzed into a basic aluminum alkali precipitated sulfate salt. This is then dried and calcined at about 950° C. Any alkali sulfate is washed out and recycled. The remainder is alumina. The ferrous sulfate is crystallized out at about 10° C. It is dried and calcined at about 450° C. to produce an iron oxide mixed with other sulfate salts that can be washed out and recycled.

Dependencies are inferred from the claim text.