Effect of operating parameters in stirred ball mill grinding of coal

Abstract

For any physical separation process to work efficiently, a high degree of liberation must first be achieved. In the case of coal, a mean particle size as fine as 5 μm may be necessary when deep cleaning is required. One of the most energy-efficient devices for producing micronized coal is the stirred ball mill In the present work, various operating parameters such as stirring speed, pulp density and the use of grinding aids have been studied using a laboratory stirred ball mill. It has been found that the mill operates most efficiently at low stirring speeds and high pulp densities, as long as the viscosity is controlled within limits. The use of grinding aids reduced the energy consumption significantly, which may be attributed to a reduction in slurry viscosity.