Ball mill - WikipediaBall mills rotate around a horizontal axis, partially filled with the material to be ground plus the grinding medium. Different materials are used as media, including ceramic balls, flint pebbles and stainless steel balls. An internal cascading effect reduces the material to a fine powder. Industrial ball mills.define a ball mill how are possible to rotate in one,The System of a ball millOct 10, 2016 . The ball mill is a hollow drum closed with loading and unloading end caps, filled with grinding media and rotated around its axis. The drum of the ball mill (Pic. 1) is a hollow cylinder of steel, lined inside with armor lining plates which protect it from impact and friction effects of the balls and the grinding.