Extraction and Recovery of Precious Metals from Plating Solutions Using Molecular Recognition Technology

Abstract

SUMMARYConventional techniques for recovery of gold from dragout, plating, or stripping solutions, produce a gold product that must first be refined, and then converted back into potassium gold cyanide (PGC) for re-use. This procedure results in subsequent refining and conversion charges. With the molecular recognition technology (MRT) process, the gold can be directly extracted and converted to the form of potassium gold cyanide, resulting in substantial savings through elimination of the various costs and controls associated with gold refining. The recovered gold does not have to be remanufactured in the form of PGC, and can be quickly recycled. The PGC is deposited on the SuperLig® resin material, and can then be readily stripped into a concentrated aqueous solution for recycling. Results of tests on a commercial gold electroplating line are presented. Results of work conducted on recovery of palladium from a dipping bath of palladium/tin chloride catalyst solution are also reviewed.