Southwire Company, LLC

National Steel Corporation

Earth Sciences Limited

Kent W Loest

John T Schaefer

Vernon R Ewing

George H Kesler

The invention is an improvement in the method for recovering aluminum values from alunite ore by roasting the ore to remove water, reducing the ore by roasting it in a reducing atmosphere to remove sulfate, optionally roasting the reduced ore in an oxidizing atmosphere to convert any sulfides formed in the second roast to oxides, leaching the calcined ore with water as a solvent to remove compounds of sulfur and alkali metals, recovering aluminum values as soluble aluminates from the residue from the leaching step by digesting it with at least one alkali metal hydroxide, removing contaminate silica from the resulting leach solution, and precipitating aluminum hydroxide from the solution, the improvement being the use of a two stage reduction of the dehydrated alunite ore, in which the ore is reduced by sulfur in the first stage, followed by a second stage reduction with another reducing agent such as hydrogen.

Process for reduction of alunite ore in aluminum recovery process

An improvement in the process for the recovery of aluminum from alunite in which potassium hydroxide is recovered from byproduct potassium sulfate by electrodialysis, further improvement being the use of sodium hydroxide from the bleed stream from the Bayer leach for use in the electrodialysis process for recovering potassium hydroxide from potassium sulfate.

Process for the recovery of aluminum from alunite

A continuous process for the production by electrodialysis of monobasic potassium phosphate from phosphoric acid produced by the wet process and potassium sulfate produced as a by-product in processes for the recovery of aluminum from alunite.

Production of monobasic potassium phosphate by electrodialysis

A process for recovering aluminum from alunite ore directed to providing a residue for the Bayer leach step substantially free of impurities so that a high A/C ratio Bayer leach liquor is produced, which comprises roasting the ore in particulate form to drive off water and sulfur as SO.sub.2 and to convert aluminum sulfate to alumina, leaching the residue containing aluminum values with water and filtering to remove potassium sulfate and other soluble sulfates, hot leaching the residue with sulfuric acid to convert the alumina therein to soluble aluminum sulfate followed by filtering to remove silicon dioxide and other solid impurities, crystallizing the aluminum sulfate to further remove impurities, heating the residue to convert the aluminum sulfate to alumina and drive off any remaining sulfur as SO.sub.2, and digesting the alumina calcine with sodium hydroxide under standard Bayer conditions at a high A/C ratio to provide a high A/C ratio solution from which a 'sandy' aluminum hydroxide is precipitated.

Recovery of aluminum from alunite ore using acid leach to purify the

A process for the production of monobasic potassium phosphate from wet process phosphoric acid and potassium sulfate by ion exchange. The application of the process is the production of monobasic potassium phosphate by ion exchange from wet phosphoric acid produced by the reaction of sulfuric acid on apatite rock and by-product potassium sulfate from processes for the recovery of aluminum from alunite.

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Broomfield, CO, United States of America

Kent W Loest