Ball mill is a grinder for reducing hard materials to powder. A ball mill grinds material by rotating a cylinder with steel grinding balls/ceramic balls causing the balls to fall back into the cylinder and onto the material to be ground.
The cylinder rotates at a relatively slow speed, allowing the balls to cascade through the mill base, thus grinding or dispersing the materials. The rotation is usually between 4 to 20 revolutions per minute, depending upon the diameter of the mill. The larger the diameter, the slower the rotation.
If the peripheral speed 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. The point where the mill becomes a centrifuge is called the "Critical Speed", and ball mills usually operate at 65% to 75% of the critical speed.
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 material continuously being recirculated back into the mill to be reduced. Various classifiers, such as screens, cyclones and air classifiers are used for classifying the discharge from ball mills.
This Ball Crusher Mills, a horizontal type and tubular running, has two warehouses. It runs along the outside gear. Materials spirally and evenly enter the first warehouse along the input hollow axis by input devices. In the warehouse, there is a ladder scale board or ripple scale board. Steel balls of different specifications are installed in the scale board. When the barrel body rotates, centrifugal force is produced. At the same time, the steel ball are carried to some height and then fall to grind and strike the material. After being grinded coarsely in the first warehouse, the material then enters into the second warehouse for regrinding. In the end, the powder is discharges by output material board.