Energy split in multicomponent grinding

Abstract

An energy split factor is defined as the ratio of energies expended when unit-mass of a mineral is ground in a mixture environment and ground alone for the same time interval. Provided the grinding path of a mixture component remains invariant in the two grinding modes and the mill power-breakage rate function correlation holds, the energy split factor can be computed from breakage rate functions or initial rates of production of fines or from data for top-size feed particles remaining unbroken as a function of time. The concept of energy split factor is highly useful for analyzing different aspects of mixture grinding. The principal implications of the analysis presented here lie in a rational and self-consistent integration of the energetics and kinetics of mixture grinding, and in the insight into hard and soft minerals interaction obtained by tracking the energy split factors of the constituents as a function of time. For illustration and verification, three sets of mixture grinding data have been employed, namely, calcite-quartz and hematite-quartz, both in 1:1 volume ratio, and dolomitehematite in four different compositions.