Some remarks on the reactor network synthesis for gold cyanidation

Abstract

Gold cyanidation in most of the plants occurs in a cascade of large tanks because this configuration offers the longest residence time and consequently the highest gold recovery. However, the long contact between the ore and the leaching solution can increases the reactants consumption by side reactions, and in some cases this conventional reactor configuration will not be the most suitable. In this paper, several configurations for a gold leaching circuit with five equal-sized reactors are investigated and the effect of different network configurations on the process performance addressed. It is showed that, for high gold content and low cyanide concentration the conventional in-series configuration is the most recommended; however, for high cyanide concentration and low gold content the in-parallel configuration is the best one. For intermediate values of gold content and cyanide concentration, hybrid configurations with parallel sections at the beginning of the circuit are the best choice. It is also showed that the optimal circuit configuration strongly depends on the gold price and cyanide cost, and for low values of cyanide price the conventional in-series configuration is the most recommended, while for high cyanide prices the hybrid and parallel configurations must be taken into account.