Application of Corundum-Mullite Castables in the Emergency Repair of Critical Sections of Hot Blast Stoves

II. Emergency Repair Procedure for the Hot Blast Outlet
The hot blast outlet serves as the core conduit of the hot blast stove; its structural stability directly impacts the operational safety of the equipment. In the event of a collapse in this section requiring emergency intervention, repairs may be executed according to the following steps:
1. Demolition and Cleanup
Carefully dismantle the collapsed section to ensure the repair area is clean and safe, thereby establishing the necessary conditions for subsequent operations.
2. Reconstruction of the Insulation Layer
Construct an insulation layer within the hot blast branch pipe using lightweight refractory bricks to create a robust thermal barrier structure.
3. Monolithic Casting
After setting up the formwork, perform a monolithic cast using corundum-mullite refractory castable. This process not only facilitates the rapid completion of repair operations but also ensures a tight, seamless connection between the hot blast branch pipe and the hot blast outlet, thereby significantly enhancing the system's airtightness.

III. Emergency Repair Process for the Combustion Port
The combustion port is a component within the hot blast stove that is highly susceptible to damage. Its repair process is similar to that of the hot blast outlet, but it must adhere to specific structural angle requirements:
1. Removal of Damaged Sections
Clear away any collapsed or damaged material to ensure that the repair substrate is intact and structurally sound.
2. Installation of the Insulation Layer
Reconstruct the insulation layer using lightweight bricks to ensure the combustion port maintains its thermal performance.
3. Segmented Formwork and Casting
Implement a two-stage formwork process within the composite brick zone to perform a monolithic casting. Upon completion of the casting, it is essential to verify that the structure achieves an inclination angle of 25°, thereby meeting the technical specifications of the original design.

IV. Emergency Repair Procedures for Other Components
Corundum-mullite castables can also be utilized for the emergency repair of various components, such as the straight sections of hot blast stove walls, the composite bricks of hot blast domes, and the junctions between hot blast branch pipes and the furnace shell. When these components exhibit localized deformation or burn-out—thereby disrupting normal production—the following repair methods may be employed:
1. Removal of Damaged Structures
Remove the damaged heavy-duty refractory bricks, ensuring that the repair area is thoroughly cleaned and free of debris.
2. Restoration of the Insulation Layer
Reconstruct the original insulation layer using lightweight mullite bricks to restore thermal insulation performance.
3. Surface Treatment
Apply a coating of bituminous paint to the surface of the lightweight bricks to enhance their corrosion resistance and waterproofing properties.
4. Segmented Monolithic Lining Installation
After setting up the formwork, install a monolithic lining in segments using corundum-mullite castable to complete the repair of the damaged sections in the upper structure of the hot blast stove.

V. Furnace Drying and Operational Management
Following repairs, areas such as the hot blast outlet, combustion port, and hot blast branch pipes must undergo a drying process strictly in accordance with the established furnace drying curve.
The drying process plays a decisive role in ensuring the full realization of the performance potential of the corundum-mullite castables, and it directly impacts the operational effectiveness of the repaired sections. Only after thorough drying can the repaired areas achieve optimal durability and stability, thereby allowing the system to transition into a normal operational state and ensuring the safe and efficient operation of the hot blast stove.