Improving copper sulfides liberation using pulse power comminution (PPC). Application to Escondida hard ore deposit

Abstract

High Pulse Power (HPP) has been developed for mining applications (comminution) in the late 70s-early 80s (Andres., 1989). The main principle of HPP is compressing a slowly stored energy (ms-s) that is delivered quickly (<10 µs) in order generate a peak of electric power. This later is then transmitted in a media chamber to create an electric arc and shockwaves that pulverize rocks. Based on these assumptions, using I-ROX HPP technologies, different experimental procedures (PPC) have been developed to investigate the selective liberation of copper sulfides minerals from Escondida hard ore deposit (partnership with BHP) using SEM automated mineralogy (SEM-MLA-AMICS). Results have been compared with conventional comminution (CC) (crushing (C-for coarse) and grinding (F- for fine)) and with initial texture of the deposit. In all PPC experiments, liberation in coarser sizes is better than in CC. During coarse crushing, a stronger Cu enrichment is observed in the fine particles created by PPC than that by CC. Other results from fine grinding show that overgrinding can be prevented, resulting in better liberation in the floatable sizes. Overall, results show 10 % increase of highly liberated particles in F-PPC compared to F-CC, most likely implying that copper recovery after rougher flotation could be equivalent/better to CC at bigger/similar particle size, respectively.