Enhancing the kinetics of chalcopyrite leaching in the Galvanox™ process

Pyrite is an effective catalyst for the atmospheric leaching of chalcopyrite in iron sulfate media via the Galvanox™ process. However, not all pyrite samples have the same catalytic effect on the process. Techniques to enhance the catalytic properties of pyrite were investigated. Specifically, the effects of pyrite treated with silver (enhanced pyrite) on the kinetics of chalcopyrite leaching were examined with the aim of improving the Galvanox™ process. It has been shown that by pretreating natural pyrite samples with miniscule amounts of silver ions, the rate of chalcopyrite leaching increases dramatically. As little as 50 ppm silver on pyrite, or about 50 g silver (about 1.5 troy ounces) per tonne of pyrite, is sufficient to ensure rapid chalcopyrite leaching kinetics in the Galvanox™ process, regardless of the source of the pyrite. With this new process, the catalytic properties of pyrite are improved such that all pyrite samples accelerate the rate of copper extraction from chalcopyrite significantly.

Research Highlights► Pyrite is an effective catalyst for chalcopyrite leaching via the GalvanoxTM process. ► Pyrite from different sources can influence the rate of chalcopyrite leaching differently. ► A strong correlation exists between the level of silver in pyrite and its catalytic effectiveness. ► Pre-treating pyrite in dilute silver solution enhances its catalytic effectiveness. ► After pre-treatment, any pyrite sample can be made a suitable catalyst for the GalvanoxTM process.