In fact, no matter which kind ball mill it is, a ball mill, a energy saving ball mill, a large ball mill, or a planet ball mill using in the university laboratory,a cement ball mil using in the cement production, the working principle of them are all basically simalar. So, the factors of affecting the revolving speed of them should have in common as well. In the operation process of ball mill, cylinder drives the medium group to do motion, during which, medium collide with the other adjoining medium and the cylinder wall; these collisions determine the motion law of medium in grinding ball. Milling process and the complexity of interactions between adjacent media increase the difficulty in understanding the characteristics of these collisions, leading the research on media motion to be more difficult, so the research areas of progress cannot quickly achieve the desired goals.

It is the complexity of media campaign that makes its research difficult to have a breakthrough. With the applications of DEM in the field of engineering, media motion modeling has been widely applied in the grinding process. Some foreign scholars use the discrete element method to calculate and simulate the movement patterns of media in the ball mill, establish a mathematical model of media campaign and take simulation with the software to simulate industrial mill medium motor behavior, and the results deduced by model are reasonably close to the experimentally determined value. The current theories include two-dimensional DEM and three-dimensional DEM.

The grinding mills grind materials at the driving of revolution and autobiography and relying on the friction and collision of the grinding balls in grinding bowl .The higher the revolving speed, the greater the function of the friction and the collision. So when the ball mill works at the formal condition, the discharging grain is basically proportional with the revolving speed of the ball grinder. The gradually promotion and wide application of modern camera technology in the research of mill medium motion are also due to the complex influence of grinding parameters on medium movement; theory research basically depends on the assumption of some parameters, which makes the theory research exist certain deviation of the actual media movement. The application of this technology makes media motion study be more in line with the actual grinding process and the results are more accurate.