Two-stage SART process: A feasible alternative for gold cyanidation plants with high zinc and copper contents

The SART process (SP) has been successfully implemented in gold cyanidation plants to address issues associated with high cyanide-soluble copper content the ores. However, this process could produce a relatively low grade precipitate, descreasing the sale price, when gold plants have high zinc and copper content in their solutions. A potential option in this case would be use of a two-stage SART process (TSSP) to produce separate zinc and copper precipitates. The additional equipment involved with this process would increase the capital cost, thereby generating concerns about the optimal range of metal contents that could justify this option. This study presents a methodology to quantify the feasible range of Cu/Zn concentrations that would justify a two-stages SART process. The study is based on a thermodynamic model and a simple economic evaluation. Results show the TSSP is preferred when the Cu/Zn ratio ranges between 0.2 and 1.5 with copper concentration higher than 500 mg/L. The TSSP appears to be a viable option to consider for gold plants having concentrations of copper and zinc higher than 500 and 350 mg/L respectively.