Cement kiln commonly used products High strength alkali brick!
Alkali brick is generally made of low alumina clay clinker with Al2O3 content of 25 ~ 30% on the basis of adding pyroxylite, coke gems and appropriate additives to improve the compressive strength of the refractory brick. It has the characteristics of high strength, stable volume, permeability resistance and alkali erosion resistance.
The alkali resistance mechanism of alkali resistant brick is that the SiO2 in it will react with the alkali metal oxide deposited in the flue gas at high temperature to form a high viscosity liquid phase, forming a layer of glazed protective layer, covering the surface of the refractory brick to block the porosity, to prevent the penetration and erosion of the alkali metal melt, and play the role of alkali corrosion resistance.
Alkali resistant brick of cement kiln is divided into ordinary type, high strength type, arch type and heat insulation type, which are mainly used in cement kiln preheater, decomposition furnace, tertiary air pipe and other parts.
The preheater and decomposition furnace are located at the end of the whole hot gas flow, and the temperature of the preheater and decomposition furnace is low, not higher than 1100℃, and the frequency and amplitude of temperature change are small. Under such calcination temperature, there is basically no liquid phase in the calcined material, and there is basically no caking and sintering. Therefore, the configuration of refractory materials in preheaters and calciners does not require too high refractoriness and too high strength, nor does it require too high thermal shock stability.
However, in the range of 800 ° C ~ 1200 ° C is the temperature area where the condensation of alkali metal oxides occurs, so under the raw and burning materials with high alkali content, the preheater is in a large range, and the refractory material must withstand the chemical erosion of alkali metal oxides.
In the four or five preheater and decomposition furnace working temperature of about 1100℃, the relative temperature is high, not only to consider the alkali sulfur gas on the erosion of refractory materials, but also need to consider the material erosion, so it is necessary to choose a high strength alkali brick with resistance to material erosion wear and erosion.
In the first, second and third preheater, the cement raw material gradually reaches about 800 ° C from normal temperature, the relative temperature is low, the erosion effect of alkali sulfur gas on the refractory is small, and the ordinary alkali resistant brick or heat insulating alkali resistant brick can be used.
