The treatment of hazardous waste in a rotary kiln usually involves several stages: drying and pyrolysis, combustion, and burnout. Under the action of high temperature, hazardous waste will be decomposed and destroyed, but will form flue gas and slag. The flue gas of the hazardous waste and some molten slag will cause damage to the refractory materials in the rotary kiln. Therefore, the proper selection of refractory materials can effectively improve the quality of the rotary kiln.
Selection of Refractory Materials for Hazardous Waste Rotary Kiln
1) High temperature resistance
In the selection of the refractory material for the inner wall of the rotary kiln, it must have high temperature resistance. The treatment of hazardous waste requires high temperature combustion. If the high temperature resistance of the inner wall is not good, it will not only affect its service life, but also affect its treatment effect. Generally speaking, the incineration temperature of hazardous waste is around 800 degree . The operating temperature in the rotary kiln is generally 850 degree 1000 degree .
2) Good strength and wear resistance
The strength of rotary kiln refractory refers to its mechanical strength. Hazardous wastes usually have different shapes and sizes, and their hardness is naturally different. If the strength and wear resistance of the material are poor, it is easy to be damaged by impact and wear when the waste enters the kiln and is turned over and dropped. In addition, dangerous goods will expand during the combustion process, and the shell of the rotary kiln will also stress the refractory material, which is bound to require the material to have good strength.
3) Good volume stability
The refractory material of the rotary kiln is closely covered with the entire inner wall of the kiln. During the normal operation of the rotary kiln, it is subjected to thermal stress caused by temperature changes, mechanical stress imposed by the rotation of the cylinder, and stress between materials. The process of temperature change will The expansion agent that brings the volume of the refractory material shrinks. When the volume stability of the refractory material is poor or the volume changes greatly at different temperatures, there will be extrusion or gaps between the refractory materials, between the refractory materials and the cylinder, causing the material to break or fall off. .
4) Good corrosion resistance
A large amount of corrosive gas and slag are generated during the incineration of hazardous waste, which will enter the material through the open pores and micro-cracks on the surface of the material, and react with the material matrix to cause embrittlement and peeling of the material. Use materials with good corrosion resistance It can reduce the penetration and reaction of harmful substances to a certain extent, and prolong the overall service life of the rotary kiln.
