Optimum choice of the make-up ball sizes for maximum throughput in tumbling ball mills

Ball size distribution for the maximum production of a narrowly-sized mill product

“…Cho et al [1] pointed out how difficult it is to determine an optimum composition of make-up balls for maximum output. The reason is the dependency of ball size distribution on many variables; these include the mill operating conditions, mill size, feed characteristics, product specifications, and grinding circuit configurations.…”

“…This is owing to the fact that each ball size effectively breaks a particular size in the mill [1,2]. The optimum ball size distribution is thus determined by the amount and combination of grinding balls of different diameters in the make-up charge.…”

“…Several researchers have proposed make-up charge policies; the underlying idea has been to maintain a steady balanced ball mill charge. The following sequel of work indicates the important milestones achieved over the years: Austin et al [3]; Austin and Klimpel [4]; Menacho and Concha [5,6]; Austin and Concha [2]); Bwalya et al [7]; Cho et al [1]; and Rivera Madrid et al [8].…”

“…Concha et al [10] and Cho et al [1] then took it a step further by successfully combining a grinding circuit model with ball wear model to optimise the make-up ball policy.…”

“…Appreciating the role of ball charge and wear rate on ball size distribution and the complexity involved with controlling the ball size distribution parameter, Cho et al [1] incorporated the information that describes variation of the grinding kinetics with ball sizes and the ball wear kinetics into grinding model and investigated the effect of the make-up ball size on the mill performance with various feed and product specifications. They found binary mixture of make-up ball sizes among other factors such as feed size, the product size, the mill diameter and the breakage parameters, to perform better than a mixture of the three ball sizes.…”