To the ball mill theory

Abstract

The motion of balls in a ball mill was the subject of research by White (1905) and Davis (1920), who considered the trajectories of the outer row of balls after they were separated from the drum wall to be parabolic. However, some experimenters in their collective work indicate that the balls, during their free movement, are thrown further than is assumed by the theory mentioned above. This circumstance was not taken into account by the theories of White and Davis. Therefore, it seems advisable to reconsider the old theory of the ball mill in order to clarify it and take into account the mutual pressure of the balls during their relative motion with respect to the drum. The subject of our next study will be the trajectory of the outer row of balls. Let us note first of all that usually the moment of separation of the ball from the wall of the drum is identified with the moment of separation from the underlying ball. Meanwhile, in reality these moments do not coincide. During the time passing between them, the lower ball continues to exert pressure on the upper one and thereby influences the nature of thetrajectory of the latter.