COMMINUTION KINETICS IN CEMENT TUBE MILLS

By employing operational data, the applicability of the following comm inution kinetics equation, to closed-circuit grinding for cement was i nvestigated. R(D-p, t)/R(D-p, 0) = exp(-k t D-p(n)) It was revealed th at the values k and n varied with the progress of comminution, though they were formerly regarded as constants. The value of n was affected by the grain size distribution, and the value of k varied with n. This relationship was expressed by the following equation. k = 5.93 x 10(- 4) x (22.5 x 10(-6))(-n) When the equation is substituted for the comm inution kinetics equation, n is the only parameter affecting the parti cle size distribution. in the grinding process. There was Sound a fixe d point P-s [D-p, R(D-p, t)/R(D-p, 0)] which satisfied all values of k and n for the same grinding time at D-p = 22.5 x 10(-6) m. Moreover, some compensation for k was required when it was less than 4 mu m.