Mechanism of leaching zinc from low-grade zinc oxide by ultrasonic enhancement

• Optimal conditions for LZO leaching were explored by one-way analysis of variance. • The difference between slag in conventional and ultrasonic environments was investigated. • The mechanism of ultrasonic promotion was investigated by kinetic leaching modeling. In view of the depletion of sphalerite and the shortage of zinc resources, zinc leaching from low-grade zinc oxide (LZO) had become an important research direction. A new technology of ultrasonic enhanced H 2 SO 4 solution leaching of LZO was proposed. The effects of H 2 SO 4 solution concentration, ultrasonic power, reaction temperature, solid-liquid ratio and agitation rate on zinc leaching rate and zinc leaching kinetics were investigated. The results showed that the leaching rate of ultrasonic-enhanced leaching under optimal conditions was 95.45 %, which was 3.61 % higher than that of the traditional leaching procedure. The kinetic analysis showed that the process of ultrasonic-enhanced leaching of LZO was controlled by product diffusion and interfacial reaction, and the ultrasonic enhancement of leaching conditions reduced the activation energy from 21.375 kJ/mol to 13.912 kJ/mol. In addition, the characterization analysis showed that ultrasound opened and dissociated the particles in the wrapped state, exposing more interfaces and accelerating the reaction. This study could accelerate the promotion and application of ultrasonic enhancement in the field of enhancement leaching of low-grade ores.