Selective Electrowinning of Mercury from Gold Cyanide Solutions.
Sheya-SAN; Maysilles-JH; Sandberg-RG
Many gold-bearing ores in the western United States also contain small amounts of mercury. The presence of mercury creates potential pollution and health hazards during several steps in gold processing. An investigation was undertaken by the Bureau of Mines to develop techniques for removing mercury from cyanide mill solutions by selective electrowinning to reduce the potential hazards. Sixty-five percent of the mercury was selectively electrowon from synthetic carbon strip solution at applied potentials of 1.00 to 1.50 V when using a mercury-coated platinum or copper plate cathode. Increasing the active surface area by using mercury-coated copper wool resulted in up to 96 pct of the mercury being electrowon from mill carbon strip solutions that contained 1.9 to 20 ppm hg, 20 to 345 ppm au, and 0.35 to 39.5 Ppm ag. About 98 pct of the silver was eletrowon with the mercury onto the mercury cathode. Gold extraction ranged between 0 and 20 pct. Results of the investigation showed that choice of cathode material was critical to the success of the process. Selectivity was not achieved using uncoated steel wool cathodes.
IH; Report of Investigations;