Establishing the effect of a decrease in power intensity of self-oscillating grinding in a tumbling mill with a reduction in an intrachamber fill

Abstract

Effect of the degree of chamber filling with the charge on efficiency of the self-oscillating grinding process in a tumbling mill has been assessed.By using the approximate analytical and experimental method, dynamic effect of increasing the self-oscillating impact action of grinding fill on the crushed material was compared with the conventional steady-state motion mode. A significant increase in average sums of vertical components of the self-oscillating collision momenta and the average sums of power of such components with a decrease in the chamber filling degree was found. Manifestation of this effect is due to the increase in the self-oscillations swing with decreasing filling. An increase in the maximum momentum values was found to be approximately 2.4 times at the degree of filling κ=0.45, 3.1 times at κ=0.35 and 5.8 times at κ=0.25. An increase by 5.7 times in maximum values of momentum power was found at κ=0.45, by 9.6 times at κ=0.35 and by 45.5 times at κ=0.25.Technological effect of significant decrease in the specific power intensity and productivity growth of the innovative self-oscillating grinding process as compared to the characteristics of the conventional steady-state process with a reduction in the chamber filling degree have been experimentally established.The process of grinding cement clinker with a complete filling of gaps between spherical grinding bodies with a relative size of 0.026 with particles of the crushed material was considered. It was found that during excitation of self-oscillations, power intensity of grinding decreased and productivity increased. A decrease in relative specific power intensity was observed: 27 % at κ=0.45, 42% at κ=0.35 and 55 % at κ=0.25. A 7 % increase in relative productivity was found at κ=0.45, 30 % at κ=0.35, and 46 % at κ=0.25.The effects established in operation have allowed us to predict rational parameters of the self-oscillating grinding process carried out in a tumbling mill with variation in the chamber filling degree