Optimization of the acid leaching process by using an ultrasonic field for metallurgical grade silicon

Abstract

In the experiment, acid leaching under an ultrasonic field (20 kHz, 80 W) was used to remove Al, Fe, and Ti impurities in metallurgical grade silicon (MG-Si). The effects of the acid leaching process parameters, including the particle size of silicon, the acid type (HCl, HNO3, HF,) and the leaching time on the purification of MG-Si were investigated. The results show that HCl leaching, an initial size of 0.1 mm for the silicon particles, and 8 h of leaching time are the optimum parameters to purify MG-Si. The acid leaching process under an ultrasonic field is more effective than the acid leaching under magnetic stirring, the mechanism of which is preliminarily discussed.