Effects of grinding media on grinding products and flotation performance of chalcopyrite

Abstract

Selective flotation has been considered the most promising strategy for treating chalcopyrite. Grinding, an essential procedure before flotation, has extraordinary significance in chalcopyrite flotation. In this study, the differences between the properties of the products obtained by grinding with cast iron ball (CIB, >3.5% C) and ceramic ball (CB, >90% Al2O3) media were investigated using various techniques: atomic absorption spectrometry, scanning electron microscopy combined with energy dispersive spectrometry, X-ray photoelectron spectroscopy, and contact angle and zeta potential measurements. The performance of chalcopyrite flotation was used as the final factor in determining the characteristics of both the grinding media. The results indicate that the Fe3+ concentration and the pH of the pulp obtained by grinding with CB medium were lower, while the dissolved oxygen content was obviously higher, than those of the pulp obtained by grinding with CIB medium. The Cu2+ concentrations were basically the same under the two grinding media systems. Furthermore, grinding with CB medium yielded products with relatively more even and smoother surface than grinding with CIB medium did. Fewer oxygen-containing floccules, i.e., FeOOH and Cu(OH)2, had formed and scattered on the chalcopyrite surface during grinding with CB medium, and this is mainly attributable to the limited local cell reaction of chalcopyrite alone. Additionally, it was found that better hydrophobicity and a lower iso-electric point of the chalcopyrite surface were achieved by grinding with CB medium. Consequently, grinding with CB medium exhibited better performance in terms of chalcopyrite recovery, which was approximately 16% higher than that obtained by grinding with CIB medium.