The rotary kiln is widely used in the fields of building materials, metallurgy, chemical industry, environmental protection, etc. It can be divided into cement kiln, metallurgy chemical kiln and lime kiln according to the different materials processed. The cement kiln is mainly used to calcine cement clinker; In the process of non-ferrous and ferrous metallurgy, such as iron, aluminium, copper, zinc, stannum, nickel, wolfram, chromium, etc., the rotary kiln can be used to sinter and roast ore, concentrate, intermedium, etc.; The lime kiln is mainly used to calcine limestones.