Enhanced flotation of chalcopyrite particles by grinding with short cylinder media

In mineral processing, sufficiently liberated target minerals by grinding is a prerequisite for successful flotation. Rod grinding produces particles with a narrower size range and better floatability through line contacts, but with a lower production capacity compared to balls (point contacts). As a result, balls remain as the preferred media for most dressing plants. However, balls produce many ultra-coarse and ultra-fine particles. Hence, grinding media with multiple contact forms could offer a compromise, which can combine the advantages of both rods and balls. In this paper, the performance of short cylinders which comminute minerals in point and line contact modes and ball grinding media were compared and evaluated using chalcopyrite as a test mineral. The grinding results show that short cylinders generate more angular particles with intermediate particle sizes and have a higher grinding efficiency compared with balls. Short cylinders selectively produce more active {1 1 2} surfaces of chalcopyrite, which possess higher adsorption capacity with collectors and were preferentially floated as the concentrate. Flotation tests confirm that the real ore particles ground by short cylinders have higher liberation degree and exhibit a higher flotation recovery of chalcopyrite than ore ground using balls. This study provides a reference scheme for the grinding and flotation optimization of valuable minerals.