Behavior and mechanism of cyanide loss in ultrasound-assisted gold leaching process

The potential effect of ultrasound was investigated, which could lead to cyanide loss or decomposition during gold leaching. The variations of cyanide concentration during gold leaching with and without ultrasound were compared. The influence of initial cyanide concentration, pH, temperature, atmosphere, natural loss, hydrolysis, and cavitation effect on the loss of cyanide was examined. The results showed that the loss of cyanide was mainly caused by hydrolysis, oxidation, and reaction with CO2 in the traditional gold leaching process. With the introduction of ultrasound, the oxidative •OH slightly increased the loss of cyanide. Comparing the concentration variations of total cyanide and free cyanide proved that ultrasound (120 W) exhibited a non-detrimental effect on the loss of cyanide in gold leaching process.