Abstract
Limestone powder was ground with a vibration mill under various vibration rates and amplitudes. 32ml/800g-powder of methanol was added as a grinding aid. The BET specific surface area SB, of ground material increased up to the grinding limit then decreased through negative grinding.
A characteristic time, t0, was introduced as a parameter to characterize each grinding condition. The variation of SB was correlated as a common curve of (SB-SB0) vs. t/t0. The curve was identical with that of Rittinger's law in the initial grinding phase and extended, beyond the grinding limit, to the negative grinding phase. Negative grinding also proceeds rapidly under a grinding condition in which the positive grinding proceeeds rapidly. The negative grinding rate can be roughly estimated from the rate of positive grinding in the range of Rittinger's law.
