The Grinding Equilibrium Size of In-Water Grinding of Silica Sand by a Planetary Ball Mill.

The limit of in-water grinding of silica sand by a planetary ball mill, which gives a much higher grinding rate than tumbling ball mills, was investigated from the viewpoint of mechanical grinding conditions. The grinding limit and subsequent negative grinding were confirmed in the in-water grinding. To do this, the product fineness was evaluated on the basis of size analysis by the laser scattering-diffraction method. As a result of a series of experiments, it was found that the grinding equilibrium size, defined as the minimum particle size determined by the size analysis, decreased as the ball size, ball density or mill's rotation was reduced. The grinding equilibrium size was well correlated with the maximum force exerting on a single ball in the mill pot within the experimental range.