The main bearing and each dial are driven by electromotor of main machine through reducer, and numbers of rollers, which are rolling in the ring, are driven by dial through plunger. After crushed by hammer crusher, the big materials become small ones and are sent to storage hopper by elevator and further sent to the middle of first dial evenly by the electromagnetic vibrating feeder and feeding pipe. The materials will be driven to the edge of dial by centrifugal force and fall down into the ring, crushed and grinded by roller, and become powder after production of three rings. The high pressure centrifugal blower will inhale air from outside and blow the crushed materials to classifier. The rotating turbo in the powder concentrator will make the coarse materials return to the mill and reground, while the fineness will mix with the air and go into the cyclone and be discharged in the discharge bin, which is at the bottom of it. The air, which mixed with very little fineness, will be purified by impulse duster and discharged by blower and muffler.