Other

Xstrata Queensland Limited

John Anthony Willis

Michael Matthew Hourn

David Winborne

Rodrigo U Ventura

Rodrigo Ulep Ventura

Precious metals such as gold can be extracted from a refractory ore using a conventional cyanide leaching step and with reduced cyanide consumption by pre-treating the ore prior to cyanide leaching. The refractory ore is pretreated by fine grinding and an initial leaching step which uses inexpensive limestone and lime to maintain the initial leach relatively alkaline. Oxygen is added to the initial leaching step and the conditions are carefully controlled to only partially oxidize the ground ore to between 9-15%. The initial leaching step can be carried out at temperatures of less than 100 degrees C. and at atmospheric pressures. The pre-treated ore is then leached by a conventional cyanide leaching step to recover the precious metal and cyanide consumption can be reduced by more than two thirds.

Reducing cyanide consumption in gold recovery from finely ground sulphide ores and concentrates

A method of processing a mineral composition comprising a refractory material the method comprising milling the composition to a particle size of P of less than 25 microns and leaching said composition with a solution comprising lime and/or limestone in the presence of an oxygen containing gas.

Growing community of inventors

Sherwood, Australia

John Anthony Willis