Ball Mills By Shandong Alpa Powder Technology Co. Ltd.

a cBall mill for the dry comminution of hard materials, especially for the ultrafine range < 10 Aum in circuit with an ALPINE ultrafine classifier.
a cGrinding drum supported in water-cooled, oil-lubricated journal bearings.
a cGrinding drum lined with tungsten carbide wear plates or with silex or ceramic elements when the requirement is grinding without iron contamination.
a cGrinding elements dictated by the type of lining.

Principle of operation

Ball mills are giant drums that are filled to between 30 and 40% of their volume with freely moving grinding media - in this case balls. The diameter of the balls is between one and several centimetres to suit the application - smaller balls for fine milling results and larger ones for coarser milling tasks.

The drive sets the milling drum into slow rotation and the bed of milling media is thus activated, i.e. the balls are lifted and then impact back against the bed. Ball mills are usually operated at 75% of the critical speed. The critical speed is the speed where, mathematically calculated, the grinding media would centrifuge out. Mills of 2 m in diameter therefore rotate in operation at about 23 revolutions per minute, which corresponds to a peripheral speed of 2.4 m/s.