Direct Electrowinning of Gold.
Elges-CH; Wroblewski-MD; Eisele-JA
Proc Int Symp on Electrochem in Min &met Processing 1984 84-19:501-512
Electrowinning gold and silver from cyanide leaching solutions has been utilized by industry for many years. Steel wool cathodes are loaded to high levels with precious metals and fire-refined to produce dore bullion. If the leaching solutions are dilute, the gold and silver are concentrated by adsorption on activated carbon, followed by desorption in order to produce a strong enough solution for electrowinning. The electrowinning cells are operated at about 80 deg c, which is the solution temperature coming from stripping. The Bureau of Mines is developing an electrowinning cell having improved mass transfer (imt) characteristics. The gold and silver are deposited onto steel wool cathodes directly from dilute leaching solutions, and the carbon adsorption-desorption step is avoided. An additional benefit is that electrolysis can be done at ambient temperatures and does not require heating large quantities of solution. By fortifying the dilute leaching solution with naoh and recirculating the electrolyte rapidly within the cathode compartment, better current efficiency and deposition rates were obtained at ambient temperature with the imt cell than with the conventional zadra cell.
Proc. Int. Symp. on Electrochem. in Min.&met. Processing, V. 84-19, 1984, PP. 501-512