Selective electrowinning of silver and gold from cyanide process solutions.
Nehl-FH; Murphy-JE; Atkinson-GB; Walters-LA
Reno, NV: U.S. Department of the Interior, Bureau of Mines, RI 9464, 1993 Jan; :1-7
The U.S. Bureau of Mines investigated the selective electrowinning of Ag and Au from cyanide solutions contaminated with Cu with the goal of decreasing the amount of Cu codeposited. Decreasing Cu codeposited will reduce refinery costs. Direct current was applied to the cell in pulsed and square wave voltages at 0.070 A. h per 150 mL of solution. Times tested for each cycle ranged from 1 to 10,000 ms. Graphite, lead, and stainless steel were evaluated as electrode materials. Square wave electrowinning at 70" C gave the best separation of Ag and Au from Cu. Applying 25 V during the duty cycle, 0.0 V the rest of the period, a duty cycle of 10 to 30 pet, and a period of 100 to 1,000 IDS gave the following results: Ag concentrations decreased from 34 to 0.1 microg/mL, Au concentrations decreased from 54 to 0.2 microg/mL, and Cu concentrations remained almost constant at 560 microg/mL.
Mining-industry; Metallurgy; Metallurgical-processes; Electrochemical-reactions; Electrolytic-refining
Report of Investigations
NTIS Accession No.
Reno, NV: U.S. Department of the Interior, Bureau of Mines, RI 9464