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:
Apr. 14, 1981
Filed:
Oct. 01, 1979
James R Valentine, Reading, MA (US);
Ravindra M Nadkarni, Arlington, MA (US);
Arthur D. Little, Inc., Cambridge, MA (US);
Abstract
Process and apparatus for recovering a precious metal, either as pure metal or in alloyed form, from a bimetallic material in which the precious metal is mechanically bonded to a base material comprising at least one base metal, e.g., copper, brass or bronze. The base material is leached off with an ammoniacal solution of an ammonium salt, preferably ammonium carbonate, using a leaching liquid containing reactive oxygen. The base metal or metals are recovered as metal compounds by thermally decomposing the resulting pregnant leach liquor; and the ammonia and ammonium salt are reconstituted for recycling. The method and apparatus are particularly suited for recovering karat gold from filled gold scrap.