Evaluation of pre-treatment methods for gold recovery from refractory calcine tailings

The South African gold mining industry has a legacy of abundant tailings dams, which have attracted the attention investors because their potential as cheaper secondary resource. In this we investigate study recovery from refractory calcine dam. Bulk mineralogy indicated silicates and iron oxides to be most phases. Scanning Electron Microscopy (SEM) showed exist in submicrometre micrometre sizes, free gold, associated with arsenic, sulphur, e.g. quartz talc. Gold by direct cyanidation was low at 17.3%. Mechanical (ultra fine grinding P80 -16µm) chemical (alkaline, NaOH) pre-treatment microwave roasting microwave-assisted cyanide leaching were investigated increase recoveries. Ultrafine effective, producing recoveries 66.5%. NaOH pre-leaching ultrafine milled material increased 71.5%. Alkaline overall for non-pre-treated material, making process preferred it is less costly than grinding. Microwave did not achieve higher alkaline or investigation highlights confirms that treatment powerful tool extraction tailings.