Waste gas of kiln outlet is introduced to the coal mill as the drying source. Raw coal is weighed and fed to the mill by a rotary disc feeder under the raw coal bin, and after dried in a drying chamber, grinded again in the grinding bin into pulverized coal which is then carried by vented gases to a high lever separator. The coarse grits are recycled to the mill for further grinding through a heavy punch lock air flap valve and a spiral conveyor; while the fine powder flow with gases into coal mill bag filter and are fed into pulverized coal bin at the kiln outlet by the spiral conveyor. Gases are purified into the atmosphere with normal gas emission density ≤30mg/m3.
