Identification of grinding kinetics of malachite copper ore using population balance model

Abstract

To liberate copper from malachite, the ore has to be reduced to appropriate size using comminution processes. Ball mills are commonly used to obtain fine particles in grinding circuits. Population balance equations can be used to model grinding kinetics in a ball mill. The aim of this study was to understand the mineralogical characteristics of malachite copper ore and identify its grinding kinetics. To achieve this, chemical analysis and petrographic studies on thin slides were carried out. Additionally, grinding tests were carried out in a ball mill using five mono-sized fractions. Short grinding cycles of 0.5 minutes were used to calculate breakage distribution functions. Longer grinding cycles up to 30 mis were used to determine specific breakage rates. The experimental results were fitted into population balance models to obtain breakage parameters that characterize the material. The parameters were used to predict particle distributions. The malachite bearing copper was found to exists among other minerals. The average concentration of copper was found to be 4.7%. The specific rate of breakage increased as particle size increased to a maximum value at particle size of 2 mm. The parameters of grinding kinetics computed parameters were applied in prediction of particle size distribution. The particle distribution produced a high degree of agreement between the simulated and experimental results. The parameters can be used in the design of ore flowsheets for processing malachite ore.