Stanley J Woyden

US Patent:

39649903, Jun 22, 1976

Filed:

Nov 4, 1974

Appl. No.:

5/520246

Inventors:

Stanley Woyden - Stamford CT

International Classification:

C25C 700

US Classification:

204275

Abstract:

This application discloses a system for recovering silver and other precious metals from waste solutions such as those used in the development of photographic film. The system includes a holding tank from which solution is pumped into a recovery tank intermittently in dependence upon the concentration of metal in solution in the recovery tank. The system operates with a substantially constant voltage across the plates in the recovery tank, with the concentration of solution in the recovery tank being maintained substantially constant by the intermittent operation of the pump. The plating tank incorporates rotating plating surfaces in combination with a circulating system which maintains a flow of solution within the recovery tank to foster rapid and uniform plating of metal.