Studies in additive grinding of minerals

The effects of solid and liquid additives on a dry grinding process were studied at four additive concentrations and two grinding times, using a laboratory vibration ball mill with calcite as the feed material, under selected milling conditions. Among the additives used, the fatty acids are the most effective followed by alcohols, other organic solvents and inorganic salts. The experimental results show that the fineness of the product increases to a maximum and then decreases with an increase in additive concentration. Statistical correlations show that the increase in surface tension and dipole moment and also decrease in viscosity and density of the liquid additives can enhance the grinding process. Based on experimental results and correlations, it is concluded that the physico-chemical properties of the additive influence the cohesive interactions among the particles and in turn the breakage mechanisms for a better grinding environment. © 1992, Society of Powder Technology Japan. All rights reserved.