The main part of the ball mill grinding of material occurs at the level of the low-speed rotation of the cylinder when the cylinder is driven by the rotary drive means, the grinding media due to the inertial centrifugal force, attached to the liner and the inner wall surface of the mill shell Together the rotation, was taken to a certain height, by the force of gravity free fall, then grinding the crushed material barrel, while in the rotating grinding mill in addition to the rise, fall outside of the circular motion, but also produce sliding and rolling, resulting in between grinding, lining and the grinding abrasive material so that the material ground. While material impact crushing and grinding ground, by the end of the feed material and the discharge end of the height difference between the material surface itself, so that the material from the feed end to the discharge end flows slowly complete the grinding operation.

Clearly, when the mill in normal operation, the state of motion of the grinding media have a great impact on the abrasive material. Can be brought to the mill at a higher, the same as the projectile falling grinding because of its high kinetic energy, so the material has a strong impact crushing capacity; height can not be brought to the mill, and the material on slide together, the material has a strong grinding capacity.

The state of motion of the mill grinding mill usually associated with speed, quality and quantity grinding mill memory of a great relationship. Because the speed of the cylinder determines the size of the grinding physical inertia generated by the centrifugal force. When the cylinder has a different speed, there will be three kinds of grinding motion states:

  1. When the cylinder speed is too low, can not be brought to a higher height grinding, grinding and material generated by gravity immediately fell, was "pouring in motion," the impact of the role of the material is very small, almost exclusively played grind effect, and thus poor grinding effect, and less productive.
  2. When the cylinder speed is too high, due to the inertia of the centrifugal force of its own gravity greater than grinding, grinding and material attached to the body wall of the cylinder, the cylinder rotates together with no land, was "the circular motion of the state." Grinding not have any impact on the material and abrasive.
  3. When the cylinder moderate speed, grinding has been elevated to a certain height the falling down, was "thrown down the state of motion", then grinding the materials have a greater impact and abrasive, grinding better.

In the Ball Mill, the number of grinding media filling fewer higher cylinder speed, the rolling and sliding grinding is also smaller, resulting abrasive material effect on the smaller, when the number of filling a lot of grinding when distributed in the grinding cylinder near the central portion of the cross section, not enough to form a projectile motion. And produce more rolling and sliding, resulting in the material by abrasive and grinding. So when grinding size bigger or harder materials, the average size of the grinding bodies to be bigger, the number may be less filling, thus ensuring grinding projectile landed with sufficient height, strengthen the role of impact crusher. Conversely, smaller or easier mill grinding materials, the grinding average size can be smaller, but the number should be more filling, which will strengthen abrasive.

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