Understanding the mechanism of microcrack-enhanced bioleaching of copper

Abstract

Investigations on the microcrack distribution characteristics and bioleaching behaviors of particles were conducted to obtain better bioleaching efficiency and deepen the mechanism understanding. Results indicate that comminution by high-pressure grinding roll (HPGR) is the desirable method for obtaining particles with more abundant and wider microcracks. Fixing the HPGR pressure at 4 MPa results in the highest bioleaching efficiency for copper extraction, namely 86% for the shaking flask bioleaching (particle size: <1.7 mm) and 52% for the column bioleaching of particles (particle size: 3.35–6.7 mm). The suggested model for reaction kinetics of microcrack-containing particles implies that more abundant and wider microcracks can promote the exposure of both Cu-containing phases and ferrous iron as well as solution infiltration, as evidenced by the COMSOL simulation results and bacteria proliferation analysis. The results highlight the importance of microcracks for enhancing the bioleaching process and provide insights for the mechanism understanding.