Why do cement rotary kilns use alkaline refractory bricks?

Why do cement rotary kilns use alkaline refractory bricks?

The raw materials for cement production in cement rotary kilns mainly include limestone (main material, providing caO), clay raw materials (providing so2, A1O3 and a small amount of FeO), calibration raw materials, but in many cement plants, iron ore is often required due to insufficient iron in the clay. powder; sometimes there is not enough silica in the clay, sandstone needs to be added; or because the aluminum content is not enough, bauxite needs to be added. This added raw material is called auxiliary (or correction) raw material, and the purpose of adjusting these raw materials is to make the content of each chemical component in the raw material meet certain requirements.

Generally speaking, limestone accounts for 80% of the raw materials for cement production in cement rotary kilns, which is the main material for cement manufacturing. Material dust and alkali, sulfur, chlorine and other alkali vapors volatilized by fuel have serious erosion on refractory materials, and with the cyclic enrichment of alkali, sulfur, hydrogen and other volatile substances and melting in the pre-decomposition system, they adhere to powdery materials and produce Skin blockage. Therefore, in the use of cement rotary kiln linings, refractory bricks with good resistance to alkaline corrosion are used.