Effect of media size in stirred ball mill grinding of coal

As a prerequisite to producing super-clean coal with any physical coal-cleaning process, such as microbubble flotation, the feed coal must be micronized to liberate finely disseminated mineral matter. The stirred ball mill is regarded as one of the most efficient devices for micronizing coal. Using a 13.4 cm batch mill, the optimum operating conditions have been determined in terms of media size, feed size and media type. The rate of breakage determined with monosized feeds are compared on the basis of specific energy consumption. It has been found that a 20:1 ball size/particle size ratio gives optimum grinding conditions.