High wear resistant castables are used in the arch bridge parts of sleeve kilns. They are the castables chosen for emergency repairs of the kiln in recent years.
The sleeve kiln is a double-cylinder kiln, and the arch bridges are also double. For example, one sleeve has 8 arch bridges, and two sleeves have 16 arch bridges. The number of arch bridges is increased or decreased according to the size of the sleeve kiln, and the number is not necessarily certain. Because this part has to bear the heavy pressure of the material, and is closely connected to the combustion chamber, as well as the erosion of the wind speed and alkaline atmosphere in the furnace lining. Under normal circumstances, magnesia-alumina spinel bricks are used, but the temperature of the sleeve kiln is not as high as that of the cement rotary kiln. C-shaped magnesia-alumina spinel bricks are more suitable.
In the case of emergency repair, the manufacturer will use castables for emergency repairs, but the selection of the type of castables is a difficult problem, because the temperature of the arch bridge of the sleeve kiln does not exceed 1300°C. If corundum castables are used, corundum will not condense well due to the low temperature. The castables must also peel off. If mullite castables are used, the erosion of wind brushes and raw materials in the furnace, coupled with the erosion of the alkali atmosphere of the white ash raw materials, cannot fully meet the use of this special part. The use of high-aluminum castables is not wear-resistant. Totally inappropriate for use in this particular area.
However, there is a prerequisite for the emergency repair of castables. If the columns on the arch bridge are damaged, it is not possible to use any kind of castables. The columns must be built with magnesia bricks before suitable castables can be used.
Since the arch bridge part of the sleeve kiln must bear load and resist wind brushing and alkali metal erosion, it is more appropriate to use high wear resistant castables because the raw materials added to the high wear-resistant castables include mullite and There is a reasonable proportion of silicon carbide, and then 1% steel fiber is added. Mullite and silicon carbide improve thermal shock and wear resistance, and steel fiber increases pulling performance. Moreover, adding silicon carbide can also prevent alkali metal corrosion. skin phenomenon.
Therefore, it is more appropriate to use multiple components of highly wear resistant castables to resist load-bearing and alkali erosion during emergency repairs on arch bridges.
