Ultrasonic-enhanced sulfuric acid leaching kinetics of high-grade germanium-containing materials

Abstract

The study is based on the application of sulfuric acid in germanium leaching process, the leaching kinetic of high grade germanium-containing materials with sulfuric acid as solvent under ultrasonic assistance was studied. The influences of reaction temperature, sulfuric acid concentration and ultrasonic power on germanium leaching process were investigated.The results showed that when the sulfuric acid concentration was 110 g/L, the leaching temperature was 90 °C the leaching time was 30 min, the liquid-solid ratio was 10, and the ultrasonic power was 700 W, the germanium leaching effect was the best, and the leaching efficiency reached 92%.The leaching reaction process of germanium conforms to the unreacted shrinking core model. In the reaction process, loose product layer will be formed on the surface of the mineral, which hinders the diffusion of the leaching agent into the mineral. The leaching reaction control step of germanium in high-grade germanium-containing materials is internal diffusion control. According to the experimental data, the macro-kinetic model of the reaction was established, and the macro-kinetic equation was obtained with Ea (apparent activation energy) of 8.76 kJ/mol, A (pre-exponential factor) of 0.102.