Leaching Complex Gold Ores
Calaverite is a gold telluride found in the Kalgoorlie region, Fiji, Cripple Creek Colorado and numerous other locations. It is known that a high pH is necessary for calaverite cyanidation, with the leach rate increasing substantially above pH 12 due to the hydroxide ion concentration.In most circumstances lime is used to achieve high pH, however lime saturates at approximately pH 12, limiting the maximum pH obtainable in a critical region for calaverite leaching.Plant observations, laboratory experiments and thermodynamic modelling show that the maximum hydroxide ion concentration that can be achieved with lime (CaO) is strongly dependent on common ions. The presence of calcium, as commonly found in saline waters, substantially diminishes the maximum pH that can be obtained with lime. Conversely the presence of sulfate ions, as generated through oxidation of sulfides, substantially increases the maximum pH that can be achieved with lime.Sulfide oxidation during cyanide leaching of complex ores may generate acid and sulfate ions,making overdosing with lime at the front of the circuit, or staged addition down the leach train, important to maintaining the maximum hydroxide concentration.
J. A. Rumball P. L. Breuer K. Phelan
Manager Metallurgical Services, Barrick Technology Centre, Canada
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
1658-1665
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）