Gold process modelling. II. The effect of ore type on leaching and adsorption dynamics at Telfer gold mine

The process of go Id cyanidation and Carbon-ln-Pu Ip/Carbon-In-Leach (CIP/C IL) is used extensively worldwide for the recovery of gold from ores. A con tinuous CIP/CIL model can be used to predict outcomes from the CIP/CIL proc essing of different ores, or for evaluating the effects of non-idealities i n CIP/CIL circuits, such as preg-robbing. in this paper a CIP/CIL model was developed which accounted for the leaching of gold from the ore, preg-robb ing of gold onto the ore surface and adsorption of leached gold onto activa ted carbon. A variable order Mintek model was used to model the kinetics of gold leaching. A film diffusion model was used for modelling the process o f preg-robbing, which has not been modelled before using experimental data. A simple film diffusion model was also used to model the adsorption of aur ocyanide onto activated carbon; The model developed was then applied to a n umber of oxide and sulphide ores. It was found that the leaching model satisfactorily described the extractio n of gold from the ore. It was also found that plant activated carbon shoul d be used for the adsorption model calibration. When the model was used to simulate the behaviour of different ores, it was found that the recovery of gold was most closely linked to the flowrate of slurry through the circuit . For refractory ores, the most important consideration was the relative ki netics of the processes of leaching, adsorption onto activated carbon and p reg-robbing at the ore surface. When preg-robbing was slower than adsorptio n, the circuit gold extraction could be improved by removing the leaching t anks, so that the preg-robbing must compete with the faster adsorption onto activated carbon. Neither the carbon distribution nor the mechanism of car bon transfer was found to have a significant effect on the extent of preg-r obbing. (C) 2001 Elsevier Science Ltd. All rights reserved.