Using advanced mineral characterisation techniques to estimate grinding media consumption at laboratory scale

Grinding media is very important in the mineral processing, mainly because its consumption involves significant costs of grinding and consequently, of the total mining operational expenditure. During grinding, chemical and physical consumptions take place. In both cases, operational variables play an important role but also mineralogy, because many pulp properties depend on it. In the present work, an experimental methodology to study grinding media consumption is proposed, following a geometallurgical approach. The methodology was applied on three Chilean copper sulfide ores to show the kind of results that can be achieved. In the laboratory case study presented, an empirical and predictive model of grinding media consumption as a function of grindability, operational variables (pulp pH and grinding time) and mineralogy, was obtained with the aid of advanced mineral characterisation techniques such as reflectance spectroscopy, X-ray diffraction and portable X-ray fluorescence. The results show that pH has an important effect on grinding media consumption, which may be due to the opposite relation between corrosion and an alkaline environment. Grindability also affects the grinding media consumption, but is related to a physical mechanism. It was found that the overall mineralogical composition and grindability of the ore may change the rate of grinding media consumption, which is greater for hard samples with highly reactive sulfide minerals. However, the highest consumption was obtained in samples with more sulfide minerals.