Behavior and mechanism of cyanide loss in ultrasound-assisted gold leaching process
(1. Key Laboratory for Ecological Metallurgy of Multimetallic Ores (Ministry of Education), Northeastern University, Shenyang 110819, China;
2. School of Metallurgy, Northeastern University, Shenyang 110819, China;
3. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China)
2. School of Metallurgy, Northeastern University, Shenyang 110819, China;
3. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China)
Abstract: 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.
Key words: ultrasound; gold; cyanidation; cyanide loss; •OH radical