Advantages of Using Dolomite Brick in Cement Kilns
The important component material of dolomite brick is dolomite. The theoretical composition of pure raw materials is MgO 42%, CaO 58%; the total amount of SiO2, Al2O3, Fe2O3 is less than 3%. The biggest Advantages of Using Dolomite Brick in Cement Kilns are its price advantage and good adhesion of kiln skin.
From the main component point of view, dolomite brick has the characteristics of easy digestion. It is broken down into pieces in 2 to 3 weeks without waterproofing. Therefore, it brings great difficulties to the use of dolomite bricks. At present, the advancement of packaging and impregnation technology has made the manufactured dolomite bricks stored for one year and then used again without problems.
Dolomite bricks are widely used in the high temperature zone of cement kilns because of their good chemical resistance.
The Advantages of Using Dolomite Brick in Cement Kilns are as follows:
(1) Excellent kiln skin performance
Because the dolomite brick is under high temperature, the cement clinker in the liquid phase will cause the surface layer of the brick body to be eroded. When the temperature rises to 1450 ° C, f-CaO in dolomite bricks will react with dicalcium sulfate in cement clinker. This creates a protective layer on the surface of the brick. And because the melting point of C2S and C3S is relatively large, the film is not easy to disappear, so the protective layer of kiln skin produced on the surface layer of the brick is relatively stable.
(2) Excellent corrosion resistance
Because there is f-CaO in the dolomite brick, it can generate a relatively strong protective film-kiln skin on the surface layer of the brick. The newly-generated kiln skin can effectively prevent the liquid phase in the cement clinker from diffusing into the brick body of the dolomite brick. It reduces the corrosion and flaking of refractory bricks. Moreover, the thickness of the newly-generated kiln skin makes the temperature of the refractory brick drop. As a result, the chemical corrosion and heat load on the refractory bricks are reduced, thereby increasing the use time of dolomite bricks.
(3) The heat loss of the cement kiln body is reduced
Because a thick protective film is formed on the surface of the dolomite brick. The temperature is reduced, and the heat dissipated through the inner wall of the rotary kiln is small. This can increase economic efficiency and reduce energy consumption.
Disadvantages of dolomite bricks
Weak resistance to hydration is the most serious weakness of dolomite bricks. In the preparation, output and other processes, it will encounter air and react with water vapor, causing it to be seriously hydrated. In addition, poor thermal shock stability leads to large-scale cracks in the cement rotary kiln when it is used intermittently, which damages the rotary kiln.
The main schemes to improve its thermal shock stability include: improving the firing system, selecting the appropriate particle gradation, adding appropriate additives, etc. More refractory fire bricks details.