The lime kiln is composed of steel shell cylinder, refractory kiln lining, rotating roller and transmission device, combustion equipment and cooling system. The refractory lining of lime kiln is used in harsh environment, and the lining body is affected by material wear, mechanical stress, thermal stress, chemical erosion and other factors. Therefore, the refractory of lime rotary kiln must have the properties of wear resistance and erosion resistance, high temperature volume stability, erosion resistance, thermal shock resistance and so on.
The following is the specific configuration requirements of refractory bricks for each part of lime rotary kiln collected and sorted by Kerui refractory manufacturer.
- Refractory for pre heating zone:
At the front end of the preheating belt is a preheater. The limestone is heated in the preheater, and the heat source is the waste gas in the cooling section. The particle size of raw materials should be 10 ~ 30mm, and the temperature entering the preheating section should be 1000 ~ 1050 ℃. The refractory materials in this area are required to have high strength, wear resistance, thermal shock resistance and other properties. Generally, clay bricks or clay bricks with good compactness are used.
- Refractory for transition zone:
The working temperature in this area is 1200 ~ 1300 ℃, which is the transition stage before the raw limestone enters the sintering zone. The temperature fluctuates greatly during this period, so some limestone has reacted. Therefore, refractories are required to have high temperature, high strength, thermal shock resistance and other properties. Generally, mullite bricks are used. At the same time, in order to make the raw materials heated and evenly distributed, during masonry, several protrusions can be added in the length direction to drive the raw materials to turn over. This material is generally the same material precast block, i.e. mullite precast block. When mullite bricks are used for masonry, the permanent layer may not be used.
- Refractory for high temperature zone:
The temperature in this area is 1300 ~ 1400 ℃, and the temperature fluctuates greatly. The refractory is required to have the properties of high load, high temperature volume stability and thermal shock resistance. Generally, high alumina bricks are used for direct masonry without permanent layer.
- Refractory for combustion zone:
Calcination zone is the final reaction stage of lime. The working temperature of this section is 1400 ~ 1500 ℃. The firing temperature is affected by the activity of raw limestone. The higher the activity is required, the higher the firing temperature will be. For the masonry of thermal insulation layer in the combustion zone, the refractory is required to have the properties of high temperature, high strength, wear resistance and so on. Magnesium rich spinel brick can be used for masonry. Add steel plate between refractory bricks. The steel plate reacts with the refractory material at high temperature to form magnesium iron spinel, which makes the masonry more firm and durable.
- Refractory for cooling belt:
The cooling system of the cooling belt is the cooling device of finished lime, which is cooled by fan. The temperature of the cooling belt is lower than 100 ℃, and the cooled lime enters the silo through the conveyor belt. The hot air temperature after heat exchange is about 600 ℃, which enters the rotary kiln for mixed combustion with the combustion body. The cooling zone is generally built with clay bricks. The temperature of several layers of bricks / castables in a small area at the front end of the cooling belt is 1300 ~ 1400 ℃, and this area can be built with high alumina bricks.