STUDY OF MERRILL-CROWE PROCESSING .2. REGRESSION-ANALYSIS OF PLANT OPERATING DATA

The recovery of precious metals from alkaline cyanide solution is acco mplished effectively utilizing the well-established Merrill-Crowe proc ess. Plant data from three silver operations were analyzed in terms of zinc efficiency, and mathematical models were generated with multiple regression techniques. Projections of the mathematical model are in g ood agreement with actual plant performance. The results of the regres sion analysis showed that the silver concentration in the feed is the dominant operating variable in determining zinc efficiency in Merrill- Crowe processing, and this is especially true for operations with low- pregnant grades. Pregnant grade and flow rate are the two operating va riables which are beneficial to zinc efficiency. Increases in sodium c yanide concentration and zinc addition result in reduced zinc efficien cy. Finally, the mathematical models indicate that modest economic imp rovement in Merrill-Crowe processing can be realized with relatively m inor modifications to the circuits.