NEWER ENERGY-EFFICIENT APPROACH TO PARTICLE-PRODUCTION BY COMMINUTION

Grinding tests on solids of varying hardness show that, in general, energy utilization in a choke-fed high-pressure roll mill is higher than in a ball mill, but lower than in the single-particle mode of comminution under slow compressive loads. The presence of moisture in feeds improves the energy efficiency of the high-pressure roll mill somewhat, presumably by reducing interparticle friction and the briquetting tendency of fines produced in the roll gap. The size distributions of ground products from the high-pressure roll mill are self-similar; the logarithmic median size decreases linearly with the fines produced, and the inverse of the median size increases linearly with the energy expended. Pressurized roll milling can be simulated satisfactorily by modifying the standard particle population balance grinding equation in order to account for energy dissipation in the tightly compressed particulate bed.