The grinding theory. Though used different medium (steel ball and steel rod are contained in ball mill and rod mill), the working theory of ball mill and rod mill are similar. When the shell move, the medium in shell be raised and down which has a impact on ore. Some medium may close to the tube wall of shell which can grind the ore. After long time grinding, the material be grinded to the correct size.
For details, the grinding theory of ball mill and rod are different in many ways. For ball mill, the grinding force of steel ball to ore is less than the impact, because the contact area is small between balls and mineral. Thus, the throwing motion of ball can produce a large impact, but it need a high rotate speed and has a higher power consumption. But for rod mill, grinding effect is better which need a lower rotate speed and has a lower power consumption.
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