A study of the factors affecting copper cementation of gold from ammoniacal thiosulphate solution

Thiosulphate leaching of gold is a proposed alternative to cyanide leaching for certain types of refractory gold ores. The most promising method for recovering gold from thiosulphate leach solutions is by copper cementation. This study focused on determining how the factors of pH/ammonia concentration, copper concentration, thiosulphate concentration, sulphite concentration, and temperature, commonly manipulated in thiosulphate leaching studies, affect gold cementation performance using copper. These factors were varied in artificial leach solutions according to the ranges typically found in literature. Both powder cementation and rotating disk electrode cementation were used to study the kinetics of gold cementation. Overall, the cementation of gold by copper from ammoniacal thiosulphate solution was concluded to be under mass transfer control. Higher temperatures and pH/ammonia concentration were determined to positively affect the rate of gold cementation. Conversely, sulphite and copper in solution were established to negatively affect cementation performance.Education, Faculty ofLanguage and Literacy Education (LLED), Department ofGraduat