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:
Jul. 09, 1991
Filed:
Jul. 18, 1989
Applicant:
Inventors:
Assignee:
Alcan International Limited, Montreal, CA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C01F / ;
U.S. Cl.
CPC ...
423 215 ;
Abstract
A process for the recovery of rare earth elements from Bayer Process red mud includes the following steps: (a) digesting red mud containing rare earth elements with a dilute acid solution, e.g. sulphur dioxide dissolved in water, to selectively dissolve the rare earth elements while leaving iron in the red mud substantially undissolved; (b) separating the solution obtained from the solid residue and (c) recovering the rare earth elements from the solution.