Suspension kiln is one of the ideal kilns for light firing of fine or powder materials. Suspension kiln is a kind of kiln in which fine granular or powdery materials are suspended in hot gas flow under the action of heat-carrying gas, and intense heat and mass transfer process occurs between gas and solid. The suspension kiln consists of several cyclones and one reaction tube, typically six cyclones and one light-fired reaction tube. The qualified raw material is added to the cyclone preheater from the feeder, and passes through the Ⅰ cyclone preheater, Ⅱ cyclone preheater and Ⅲ cyclone preheater in sequence. The whole preheating process is completed through the suspension, separation and deposition process for many times, and is preheated to 600 ~ 700℃, and the carbonate part is decomposed into the reaction tube for light burning. The light burning of the material is mainly completed in the reaction tube. At the bottom of the reaction tube, at about the same level as the feed point, fuel is sprayed into the reaction tube by the burner, mixed with the secondary air from the cooling system at a temperature of 600 to 700 ° C, and burned. The heat released by combustion is immediately absorbed by the material suspended in the air stream, and the material decomposition is completed instantly. The lightly fired material is taken by gas into the finished aggregate where the finished material is collected, separated and passed through the cooling system, where the material is cooled by a two-stage cyclone cooler and then discharged from the kiln. After secondary cooling, the material is reduced from 850 ~ 950℃ to below 300℃. Suspension kiln is suitable for roasting fine particles or powder with particle size less than 3mm. Fuel is mostly gas fuel and liquid fuel.