Refractory Bricks for Cement Kiln
June 01, 2018
Cement rotary kiln is a kind of construction material equipment, which is a kind of lime kiln. Rotary kiln can be divided into cement rotary kiln, metallurgical chemical rotary kiln and lime rotary kiln according to the different material. Cement rotary kiln is the main equipment of cement clinker dry process and wet process production line.
According to the different heating methods, it is divided into two types: internal heating and external heating.
Materials in the internal heating rotary kiln is directly contact with flame and flue gas,can be adjusted to realized internal oxidation or reducing atmosphere, the inner wall of the cylinder masonry refractory brick,high strength wear-resistant castable for lining, head and tail cover are flexible seal with the cylinder, can completely eliminate dust and material leakage. Multi gear support can be adopted to make the barrel length reach 60 meters, and max using temperature can reach 1600℃. For large production,the applicable fuel is liquefied gas, natural gas, gas, fuel oil, pulverized coal, coal and so on.
Material in external heating rotary kiln is not directly contacted with flame and flue gas. The heat source is between the heating furnace and the cylinder, through heat transfer of the heat resistant steel cylinder wall, and the lining of the heating furnace is refractory fiber, which can save energy and reduce consumption. By the method of heating and tube material limit, general cylinder length is less than 15 meters, heating temperature are less than 1200℃. The output is small, and the heating mode is suitable for electric heating, gas, fuel, coal and so on.
Generally decomposition zone is used with spalling resistant high alumina bricks, silicon mullite brick is superior in performance to the spalling resistant high aluminum bricks, life is the twice than high alumina brick, but price high, the kiln inlet can be adopted silicon carbide castable with anti skinning.
Transitional zone burning zone
The kiln coating of the transition zone is unstable, which requires the kiln lining to resist the atmosphere with good ability, good thermal shock resistance, small thermal conductivity and wear resistance.It uses of spinel magnesia brick, but the high thermal conductivity of the brick,with high the cylinder temperature, heat consumption large, is not conducive to reducing energy consumption. The thermal conductivity of the silicon brick is small and wear-resistant,its performance can be compared to the spinel magnesia brick.
Burning zone temperature is high, intense chemical reaction, requirement of lining erosion resistance and anti clinker, strong ability of anti CO2 SO3.It’s commonly used spinel magnesia brick at abroad, but the adhering coating is more difficult, and the dolomite brick thermal shock resistance is not good, easy hydrated; The spinel magnesia brick is better in coating, but the cost is too high. The low chrome periclase spinel compound brick used in good condition.
Cooling belt and kiln
The temperature of the cooling belt and the kiln is about 1400℃, the temperature fluctuates greatly, the grinding of clinker and the scour of air flow are very serious. The requirements of thermal conductivity lining small, wear resistance and thermal shock resistance is good; alkaline brick has excellent thermal shock resistance, such as the high alumina bricks suitable for the cooling zone.The spinel brick’s coefficient of thermal conductivity is big, and the wear resistance is not good. We use anti-spalling wear-resisting bricks instead.
In the entrance of the kiln, castables with good thermal shock resistance are used. Such as abrasion resistance and thermal shock resistance of high alumina bricks or steel fiber reinforced castable and low cement high alumina castable, but in the high temperature of the large kiln entrance is used ordinary or steel fiber reinforced castable.