Southwire Company, LLC

National Steel Corporation

Earth Sciences Limited

Vernon R Ewing

George J Hartman

Kent W Loest

An improvement in processes for recovering aluminum from alunite ore which processes include roasting the ore to remove water of hydration, removing sulfur and potassium compounds from the roasted ore by a procedure including a first leaching step resulting in a residue and a solution containing potassium sulfate, effecting partial recovery of potassium sulfate from the solution by crystallization with some potassium sulfate being bled off from the mother liquor, converting aluminum values in the residue to alkali metal aluminates by digesting the residue with alkali metal hydroxide including a substantial amount of sodium hydroxide, removing silicon from the alkali metal aluminates leaving a waste desilication product, recovering aluminum values from the desilicated aluminates by precipitation, circulating the mother liquor from the precipitation step to digestion as contaminated sodium hydroxide is bled off, the improvement which comprises enhancing the economics of the overall process by introducing therein an ion exchange procedure in which potassium hydroxide for the first leaching step is produced through ion exchange by use of potassium sulfate and sodium hydroxide, a further improvement being the use of the desilication product as the ion exchange agent.

Process for recovering aluminum from alunite

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.

Production of monobasic potassium phosphate by ion exchange

An improvement in processes for recovering aluminum from alunite ore which processes include roasting the ore to remove water of hydration, removing sulfur and potassium compounds from the roasted ore by a procedure including a final leaching step resulting in a residue and a solution containing potassium sulfate, effecting partial recovery of potassium sulfate from the solution by crystallization with some potassium sulfate being bled off from the mother liquor, converting aluminum values in the residue to alkali metal aluminates by digesting the residue with alkali metal hydroxide including a substantial amount of sodium hydroxide, removing silicon from the alkali metal aluminates leaving a waste desilication product, recovering aluminum values from the desilicated aluminates by precipitation, circulating the mother liquor from the precipitation step to digestion as contaminated sodium hydroxide is bled off, the improvement which comprises enhancing the economics of the overall process by introducing therein an ion exchange procedure in which potassium hydroxide for the first leaching step is produced through ion exchange by use of potassium sulfate and sodium hydroxide, a further improvement being the use of the desilication product as the ion exchange agent.

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Denver, CO, United States of America

Vernon R Ewing