Ball mill is widely used for milling various kinds of ores or rocks in metal and non-metal mining and building material industry.The main bearing of the Ball mill with the shell diameter 900-2100mm is spherical liner bearing; for the shell diameter 2700mm, the main bearing is completely closed self-aligning 120bearing with strong alloy of high lead and low tin with low hardness, underneath laid with cooling copper piping full of water The bearing is of static pressure structure with high and low pressure united oil lubricating system. A Ball mill operates by rotating a cylinder with steel grinding balls, for the ball to fall back into the cylinder and onto the material to the ground. The rotation is usually between 4 to 20 revolutions per minute, depending upon the diameter of the mill. The larger the diameter is, the slower the rotation will be. If the peripheral of the mill is too great, it begins to act like a centrifuge and the balls do not fall back, but stay on the perimeter of the mill Ball mills are generally used to grind material 1\4 inch and finer, down to the particle size of 20 to 75 microns. To achieve a reasonable efficiency with ball mills, they must be operated in a closed system, with oversize continuously being recalculated back to the mill to be reduced.