| Summary: | 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.
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