Investigation of energy consumed characterization of mixture grinding in the ball-and-race mill

Abstract

In this paper, grinding experiments of mixtures of super clean anthracite coal and pyrite or calcite in different volumetric ratios are conducted on a Hardgrove machine, with a power meter. Mass weighted Moh’s Scale of hardness of mixture is incorporated into the classical coal breakage model of t10 vs grinding energy, and this modified model can describe the energy-size reduction of mixture grinding. Interaction between components is embodied with energy and energy split phenomenon is discussed based on this mind. Based on the energy balance calculation of heterogeneous grinding, energy split factors (ESFs) of components in the ball-and-race mill at different grinding time are firstly computed. These two energies are calculated by the modified model with parameters in the mixture and single breakage, respectively. Interaction between components changes energy efficiencies of components in mixture grinding. ESFs of coals in mixtures are smaller than 1, which means less energies are required to yield the same t10. Only ESF of calcite is bigger than 1. On the other hand, ESFs of components change with not only grinding time, but also volumetric proportion of components in mixture.