Effects of Ball Size Distribution and Mill Speed and Their Interactions on Ball Milling Using DEM

A comprehensive investigation was conducted to delineate the effect of ball size distribution, mill speed, and their interactions on power draw, charge motion, and balls segregation in a laboratory-scale mill. The mill was simulated at different critical speeds with different mill fillings. In total, 165 scenarios were simulated. When the mills charge comprising 60% of small balls and 40% of big balls, mill speed has the greatest influence on power consumption. When the mill charge is more homogeneous size, the effect of ball segregation is less and so the power consumption of the mill will be less affected. The shoulder angle compared to the toe angle is more affected by the increase in mill speed. The small balls move to the outer layer of the ball charge and interrupt the contact of big balls with the mill liners and lifters and preventing them from rising and their presence in the cataracting regime and this is exacerbated when the small ball fraction increase. The big balls mostly appear in the cascading flow region, and then more involved in the attrition breakage mechanism, and this is exacerbated when the mill speed increase.