Abstract
Cement industry depends mainly on grinding which is an energy intensive unit operation. Thus, understanding the behaviour of cement raw materials grinding is a vital issue. Therefore, this paper considers batch ball mill grinding of cement raw materials according to different grinding schemes, including single grinding of each component (clay quartzite, limestone) separately and grinding them together in ternary mixtures. The applied energy levels were verified for both schemes. In addition, in the ternary mixtures case, the ratio between the components was changed. The results were judged in light of the product size distribution at specified level of energy and the energy distribution between the mixture components. It was found that increasing the grinding energy level sharply affects the Gaudin-Schumann size modulus of the ground material whether was ground as single or a mixture. On contrary, the energy influence on the Gaudin-Schumann distribution modulus was minor. It was also found that the modified Charles equation for energy calculation (in mixture grinding) expresses very well the energy distribution between the mixture components. The energy distribution among the mixture components depends to a large extent on the hard component portion which enhances the grindability of the soft ones. For that reason quartz utilizes only 96% of its predicted energy in the mixture 1: 2: 1 at any applied level of grinding energy.