The main motor drives the millstone to rotate through the reduction box, meanwhile, the air flow gets into the mill through air intake. The materials come out of the screw feeder and fall on the center of the millstone, and then they will move from the center to the edge of the millstone under the affect of centrifugal force. When they move across the grinding zone, they will get grinded by the rollers. The materials in the air flow will go through the rotor vanes on the separator above. The coarse powder will go back to the millstone while the eligible powder will go out of the mill together with the air flow and get collected by the powder collector. Those collected powder is the final products of the LUM grinding mill. The final products can be in different fineness through adjusting the rotating speed of the rotor of the powder concentrator.