| Abstract
| - Grinding tests were conducted under various conditions to characterizethe breakagecharacteristics of coal−water mixtures. Five bituminous coalswere ground in a conventionaltumbling ball mill for different times at solids concentrations of40−70% by weight, with andwithout the use of a dispersant. For a given coal, the grindingrate decreased as the solidsconcentration increased, whereas grinding at a higher solidsconcentration produced a higherproportion of fines, giving a flatter distribution. However, evenat the highest slurry density,the product size distribution was steeper than the broad sizedistribution recommended formaximum solids loading and minimum viscosity. Additional grindingtests were performed in astirred ball mill, aiming at a two-stage grinding method for producingcoal−water mixtures. Onthe basis of the breakage parameters obtained from the laboratorytests, simulations wereperformed to analyze an industrial scale two-stage grindingcircuit.
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