Mechanical Activation Mechanism of Cassiterite Based on Copper-Based Grinding Media

Abstract

During grinding, the abrasion and corrosion of the grinding media generate metal ions, thereby affecting mineral flotation separation. In this study, the mechanical activation mechanism of cassiterite by copper-based media was investigated via grinding and micro-flotation experiments, inductively coupled plasma optical emission spectroscopy (ICP-OES), solution chemistry calculations, X-ray photoelectron spectroscopy (XPS) and Density functional theory (DFT). Compared with ceramic medium, copper-based medium enhanced the grinding technical efficiency of cassiterite and improved the flotation recovery. Mechanism study revealed that the increase Cu ions content in the pulp of cassiterite grinding products was the main contributor to the mechanical activation of cassiterite by copper-based grinding media, and the main forms of Cu in the solution were Cu2+, Cu(OH)+ and Cu(OH)2. XPS results demonstrated that the Cu components adsorbed on the surface of cassiterite as Cu(II) and Cu-O groups. Meanwhile, DFT calculation results shown that the Cu components were spontaneously adsorbed on the surface of cassiterite (110) in the following order: CuOH+ < Cu(OH)2 < Cu2+. Therefore, the adsorption capacity of BHA increased. These results indicate an improvement in the flotation behavior of cassiterite mechanically activated by copper-based grinding media.

Keywords: mechanical activation, cassiterite, grinding media, grinding technical efficiency, flotation