Leaching Kinetics of Germanium in Vacuum Slag in HCl-CaCl2-H2O Solution

Abstract:

In order to provide a theoretical basis to improve the leaching rate of germanium in vacuum slag, the leaching kinetics of germanium in vacuum slag was investigated in hydrochloric acid-calcium chloride solution. The results show that the leaching process fits the generation of solid products of unreacted-core shrinking model. The kinetics equation is 1–2/3x–(1–x)2/3=4.66×10-3CHCl1.027CCaCl21.046d-0.862exp(–21068/RT)t. The leaching process is controlled by the diffusion of the lixiviant and the activation energy is determined to be 21.068 kJ/mol. The leaching speed and the leaching rate of germanium are increased by increasing the hydrochloric acid concentration, the calcium chloride concentration, the leaching temperature and the liquid-solid ratio and decreasing the particle size of the sample.

Key words:germanium; vacuum slag; hydrochloric acid; calcium chloride; leaching kinetics