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. 05, 1988
Filed:
Sep. 24, 1986
Applicant:
Inventors:
Wasyl Kunda, Edmonton, CA;
Thomas H Etsell, Edmonton, CA;
Assignee:
The Governors of the University of Alberta, Alberta, CA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22B / ; G03C / ;
U.S. Cl.
CPC ...
430398 ; 7511 / ; 210721 ; 210737 ; 210749 ; 210766 ; 210912 ; 423 23 ; 430399 ; 430400 ;
Abstract
In a process for recovering silver from spent photographic treatment solution comprises mixing nitric acid with a quantity of the treatment solution to precipitate from the solution silver sulfide. The silver sulfide may be then converted to pure silver. The improvement comprises mixing less than two parts of concentrated nitric acid solution with more than ten parts of the treatment solution to precipitate out of solution silver sulfide. The solution is filtered to remove the silver sulfide precipitate from the solution to yield a solid residue which includes silver sulfide.