1. Emergency Repair of the hot blast stove
When a blast furnace's hot blast stove collapses, mullite corundum concrete is an ideal repair material. While it does not require high-temperature firing, it offers greater airtightness than refractory bricks. Compared with composite bricks, its advantages are more significant. The production cycle for composite bricks is long, including production, preparation, and other steps. Furthermore, emergency blast furnace repair is difficult due to the wide variety and limited number of types available. Mullite corundum concrete can be produced quickly. The specific work involves dismantling the collapsed section, installing lightweight bricks in the hot blast stove, installing the formwork, and casting the entire structure with mullite corundum concrete. This repair method not only allows for faster repairs but also strengthens the connection between the hot air bypass pipe and the outlet, improving airtightness.
2. Emergency Repair of the Hearth Window
The hearth window of a blast furnace is a vulnerable part. In an emergency, mullite corundum concrete can also be used. The maintenance procedure is similar to that for the hot air outlet. First, the damaged part is removed and lightweight bricks are laid as an insulating layer. Next, a two-stage formwork is installed over the assembled bricks, and the entire structure is poured until the angle of inclination returns to the original 25°, thus restoring the hearth window to service.
3. Emergency Repair of Other Parts
Mullite corundum concrete can also be used for emergency repairs of the straight section of the blast furnace wall, the assembled bricks of the hot air roof, and the connection between the hot air bypass pipe and the furnace shell. If the heavy bricks in these parts are deformed or burned, even if the distance is small, and this affects normal production, they can be repaired with this concrete. During the operation, the damaged area is first removed, the insulation layer is repaired with lightweight mullite bricks, and then asphalt paint is applied to the surface of the lightweight bricks. After the formwork is installed, the corundum-mullite concrete is poured in stages to completely repair the damaged area of the blast furnace top.
4. Importance of Firing in the Furnace
Whether repairing the hot blast stove, the combustion chamber, or the hot air branch, post-repair firing must follow a reasonable firing schedule. Only scientific firing can ensure the optimal performance of the corundum-mullite concrete and the normal and safe operation of the blast furnace.
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