Chlorine and cyanide leaching of gold-bearing refractory ores

A leaching process of gold-bearing refractory and complex ores has been studied by using chlorine dissolved in brine solutions comparing these results with a standard cyanidation process. Chlorine is locally generated with the same brine solution by electrolysis that also produces the sodium hydroxide needs for the proposed process for the neutralisation phase of the barren solutions. These precipitation reactions restore the presence of NaCl that may be recycled in the process after a suitable pre-treatment. Some simulation and experimental results are present to highlight limits and advantages of the proposed process. A comparison with conventional cyanidation has been also reported.