Autoclaving Circuit

From acidulation the slurry passes to the autoclaving circuit. High-pressure oxidation of refractory gold ores and concentrates is performed in order to enhance their amenability to cyanide leaching. Oxidation conditions are critical to the chemistry within the autoclave and can significantly affect gold extraction. Important paramaters in the oxidation of refractory gold ores under oxygen pressure are the finess of grinding; the pressure, temperature, density and pH of the slurry in the autoclave; and the total retention time.

The combination of abrasion, low pH, high temperature, and high pressure restrict the selection of autoclave materials to titanium, titanium-clad carbon steel, or acid-resistant brick-lined carbon steel.

After autoclaving, the slurry is cooled in flash towers and tube heat exchangers before being sent to the neutralization circuit.

The above photograph shows an autoclave at Barrick's Goldstrike Property.