Study of the Effect of the Mineral Feed Size Distribution on a Ball Mill Using Mathematical Modeling

In this paper, the effect of the feed size distribution was studied for a ball mill. Copper ore of 0.5% was tested using batch-grinding tests. Samples were carried out using three reconstructed feed size distributions in an experimental ball mill. The size distribution was reconstructed using the double Weibull formula, and modeled using the selection and breakage functions. Copper ore samples were grinding up to 15 min. A nanosize (-19+12.5), coarse (-19+6.3 mm), medium (-4.75+0.6 mm), and fine (+0.425-0.038 mm) particle size distributions were tested. The 0.32 m diameter test mill was run at 38% volume loading and Nc (critical speed) of 68% (50.85 rpm). Breakage rate parameters were calculated and simulated for each size distribution in an industrial mill. The results show that the change in the feed size distribution has an impact on the grinding kinetics. The curves show that the mono size fraction has the highest specific rate of breakage. It is also important to note that, as the size distribution F80 decreases the power consumption increases.