The raw materials through a hollow shaft neck into the hollow cylinder grinding. Cylinder are equipped with various diameters of the steel balls, when the cylinder around a horizontal axis at a certain rotation speed, ball and raw materials in the barrel is arranged in the role of the centrifugal force and friction force, with the cylinder reaches a certain height, when their own gravity is greater than the centrifugal force, from the inner wall of the barrel body projectile falling or roll, due to the impact force and shot down broken ore. At the same time, in the process of grinding, the sliding movement of the steel ball to each other also produce the grinding effect. After grinding the material through the hollow shaft discharge. Due to continuous feeding into the material, the pressure of the material from the material to the end of the material feeding end, wet grinding, the material is carried away by the water, dry grinding, the material is taken out of the air flow away.