Materials vertically fall into the impeller rotating with high speed from the top of the machine. Under the high-speed centrifugal force, materials will have high-speed collision and crushing with the other parts of materials that are distributed around the impeller. After mutual crushing, materials will mutually hit, rub and then be crushed in the space between impeller and enclosure and finally will be discharged from the bottom of the machine. The whole process will form a closed circulation and screen equipment will be used for controlling the required granularity of final products.