2017年11月2日星期四

Principle of Selection of Refractories for Cement Kiln

refractory material
refractory material
Preheat zone and decomposition zone
The temperature of these two places is relatively low,  refractory material requiring brick lining of the thermal conductivity is small, good wear resistance, in this area from raw materials, fuel sulfuric acid base and chlorinated alkali began to evaporate, in the kiln condensation and enrichment, and infiltration brick internal. Ordinary clay brick and alkali reaction to form kaolinite and garnet, so that the brick surface crisp, brick body expansion caused by cracking peeling. And containing Al2O3 25% ~ 28% and SiO2 65% ~ 70% of the alkali-resistant or alkali-resistant insulation brick at a certain temperature and alkali reaction, the brick surface immediately formed a layer of high viscosity glaze layer, to prevent the Peeling, but this brick can not resist the use of more than 1200 ℃ temperature. So the preheating zone is generally combined with high alumina refractory bricks, anti-peeling high alumina bricks or resistant to alkali brick.
Decomposition with the general use of anti-peeling good high alumina brick, silicon brick in the performance is better than the anti-peeling good high alumina brick, life than peeling off the high alumina brick about twice as high, but the price is higher, kiln The tail feed should be made of anti-crusted silicon carbide castable.
Transition zone and firing zone
Transition zone kiln leather is unstable, require kiln lining resistance to climate change ability, good thermal shock resistance, thermal conductivity is small, wear. Foreign recommended magnesium aluminum spinel brick, but the thermal conductivity of the brick, the cylinder temperature is high, the relative heat consumption is large, is not conducive to reducing energy consumption. Domestic silicon Mo brick thermal conductivity is small, wear, its performance to a certain extent, comparable with imported materials.
Burning zone with high temperature, intense chemical reaction, requiring brick lining anti-clinker erosion, anti-SO3, CO2 capacity. Foreign generally use magnesium aluminum spinel brick, but the brick hanging kiln skin is more difficult, and dolomite brick thermal shock resistance is not good, easy to hydrate; foreign magnesium iron spinel brick in the hanging kiln skin effect is better , But the cost is too high. The use of new low-chromium perovskite composite spinel brick use is better.
Cooling belt and kiln mouth
Cooling zone and kiln temperature as high as 1400 ℃ or so, the temperature fluctuations, clinker grinding and air erosion are very serious. Requirements of brick lining of the thermal conductivity is small, wear resistance, thermal shock resistance; good thermal shock resistance of alkaline bricks, such as spinel brick or high alumina brick for cooling zone. Foreign generally recommended the use of spinel brick, but the spinel brick thermal conductivity, and wear resistance is not good. Most of the domestic use in recent years, silicon-resistant brick and anti-peeling good wear-resistant brick.
Kiln parts of the use of good resistance to thermal shock castable. Such as: wear-resistant heat-resistant high-alumina brick or steel fiber toughened castables and low-cement high-alumina refractory castable, but the kiln temperature is very high in the large kiln is the use of ordinary, or steel fiber toughening Of the corundum castable.
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