Jul 27, 2020 Select the ball mill according to the grinding sizes. Because the overall operation cost of the ball mill is high, so the ball mill is generally used for the regrinding of two-stage grinding, and the particle size of the material is relatively fine. Usually, the feeding particle size range is 20-30mm, and the particle size of the product is 0-3mm. This means that in operation, the pebble crusher remains in an intermittent operating state. The size of the ball mill is slightly undersized, which could explain why the circuit is unable to reach the designed product size (115 m). Furthermore, the operating capacity of the ball mill has reached 90% capacity, running at near full load. James M. Ekmann, Patrick H. Le, in Encyclopedia of Energy, 2004 5.2 Milling of Pulverized Coal. At the mill, fine grinding of coal involves producing coal particle sizes such that 70% or more are finer than 75 m (200-mesh) to ensure complete combustion and minimization of ash and carbon on the heat exchanger surfaces. Three types of mills, according to speed, are available low-speed mills ...