Study of chalcopyrite oxidation in hydrogen peroxide-ethylene glycol system

Chalcopyrite leaching with hydrogen peroxide as an oxidant in the presence of ethylene glycol was investigated. The addition of a small amount of ethylene glycol improves copper dissolution significantly. The mechanism of chalcopyrite dissolution was established by examining the influence of various parameters on reaction rate in the presence of ethylene glycol. The effect of temperature on the reaction kinetics, the linear relationship of reaction rate constant with the inverse particle radius and an activation energy of 30 kJ/mol suggest that the leaching reaction is surface reaction controlled. Stirring speed and sulfuric acid concentration do not impact the reaction rate. Ethylene glycol stabilizes hydrogen peroxide, even at higher temperature. Electrochemical Impedance Spectroscopy was used to investigate the effect of ethylene glycol on the chalcopyrite-solution interface. The two time constant electrical equivalent circuit for two different layers on the chalcopyrite surface was identified. No significant effect of ethylene glycol on the electrical properties of sulfur layers was observed.