Breakage properties of some materials in a laboratory ball mill

Crystalline quartz, silicon carbide, three coals of different rank and a cement clinker were studied in a small laboratory ball mill under standard conditions. The first-order specific rates of breakage and the cumulative primary daughter fragment distributions were determined. Two coals showed a slowing down of breakage rate at fine dry grinds. Anthracite showed an acceleration of grinding rate. Wet grinding was first order in all cases even to very fine grinds. Wet grinding was always faster than dry grinding for a given material but the shapes of the size distributions were the same within experimental variability.