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:
Oct. 03, 1978
Filed:
Sep. 19, 1977
Murry C Robinson, Don Mills, Ontario, CA;
Other;
Abstract
Ores or mineral mixtures containing zinc sulphides and magnesium and/or calcium in the form of carbonates, oxides and/or hydroxides are leached with an aqueous sulphur dioxide bearing solution to selectively dissolve magnesium and/or calcium leaving the zinc sulphides in the undissolved residue in concentrated form. During the dissolution reaction, the pH is maintained within the range of about 1 to about 4 by the addition of sulphur dioxide to the leach solution at a rate at least sufficient to replace sulphur dioxide taken up in the dissolution of magnesium and/or calcium thereby promoting selective dissolution of the magnesium and calcium compounds and non-dissolution of the zinc sulphides.