Roller press, also known as extrusion mill and roller mill, is a new type of cement energy-saving grinding equipment developed in the mid-1980s. It can replace the pre grinding system of ball mill with high energy consumption and low efficiency, and reduce steel consumption and noise. It is suitable for the construction of new plants and the technical transformation of old plants, so as to increase the output of ball mill system by 30-50%. In the extruded material cake, 0.08mm fine material accounts for 20-35% and less than 2mm accounts for 65-85%, The internal structure of small particles is filled with many small cracks due to extrusion, and the grindability is greatly improved. The roll surface adopts thermal surfacing, which makes the maintenance of wear-resistant layer more convenient.