Grinding kinetics, modeling, and subsieve morphology of ball mill grinding for cement industry ingredients

The dependence and interactions of various factors affecting the ball mill grinding like diameter of ball, particle size, and time of grinding on 80% passing size of product d(80) was studied for cement industry raw materials of lime stone and sand using Box-Behnken design of response surface experiments. The bond grindability index and work index of ball mill were determined for different feed characteristics by varying the number of balls involved in grinding operation in the ball mill. The higher specific rate of breakage was obtained for new or smooth surfaced balls than old or rough surfaced balls. The reduction in size due to ball mill grinding was found to be better for wet grinding than dry grinding based on specific rate of breakages obtained. The subsieve morphology of particles in sieve pan for sand for both dry and wet grinding were analyzed using scanning electron microscopic observations to determine the breakage characteristics.