The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 21, 1977
Filed:
Mar. 24, 1976
Kent W Loest, Broomfield, CO (US);
Southwire Company, Carrollton, GA (US);
National Steel Corporation, Pittsburgh, PA (US);
Earth Sciences, Inc., Golden, CO (US);
Abstract
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.