Corundum mullite castable is an excellent repair material for hot blast stoves. Compared to refractory bricks that have undergone high-temperature sintering, this material, despite not being sintered, exhibits superior gas tightness, making it particularly suitable for emergency repairs in critical parts of hot blast stoves. When hot blast outlets, combustion ports, and other areas collapse or are damaged, traditional brick repair methods involve multiple steps such as production and pre-laying, and due to the wide variety and limited quantity of bricks, they are difficult to meet the demand for rapid repairs. Using corundum-mullite castable for repairs can effectively shorten the repair cycle and improve operational efficiency.
Emergency repair process for hot air outlet
The hot air outlet is the core channel of the hot air stove, and its structural stability directly affects the operational safety of the equipment. When the part collapses and requires emergency treatment, the following steps can be taken for repair:
1. Demolition and Cleaning: Reasonably demolish the collapsed part to ensure that the repair area is clean and safe, creating conditions for subsequent operations.
2. Reconstruction of the Insulation Layer: Build an insulation layer using lightweight bricks inside the hot air branch pipe to form a good thermal insulation protective structure.
3. Overall Casting and Forming: After setting up the mold, use corundum mullite refractory castable for overall casting. This process not only enables rapid completion of the repair work but also achieves a tight connection between the hot air branch pipe and the hot air outlet, significantly enhancing the sealing performance of the system.
Emergency repair process for combustion port
The combustion port is a highly vulnerable part of the hot blast stove, and its repair process is similar to that of the hot blast outlet, but it must meet specific structural angle requirements:
1. Remove and clear the damaged or collapsed area to ensure that the repair base surface is complete and solid.
2. Insulation layer construction: Use lightweight bricks to rebuild the insulation layer to ensure the thermal performance of the combustion port.
3. Segmented formwork casting: Implement a two-stage formwork casting process in the composite brick area for overall casting. After casting, ensure that the structure reaches a 25° inclination angle to meet the technical requirements of the original design.
Emergency repair process for other parts
Corundum-mullite castable can also be applied for emergency repairs of various parts such as the straight section of the hot blast stove wall, hot blast dome composite bricks, and the connection between hot blast branch pipes and the stove shell. When the aforementioned parts experience local deformation or burn damage that affects normal production, the following repair methods can be adopted:
1. Remove the damaged structure and clear away the damaged heavy bricks to ensure that the repair area is clean and free of debris.
2. Repair the insulation layer. Use mullite lightweight bricks to rebuild the original insulation layer and restore its thermal insulation performance.
3. Surface treatment. Apply asphalt paint on the surface of the lightweight bricks to enhance corrosion resistance and waterproofing.
4. Segmented overall lining. After setting up the molds, use corundum-mullite castable in segments for overall lining, completing the repair of damaged parts on the upper part of the hot blast stove.
Oven drying and operation management
The repaired hot air outlet, combustion port, hot air branch pipe, and other parts must be baked strictly in accordance with the established baking curve. The baking process plays a decisive role in fully exploiting the properties of corundum-mullite castable, directly affecting the performance of the repaired parts. Only after sufficient baking can the repaired parts achieve optimal durability and stability, thereby transitioning to normal operation and ensuring the safe and efficient operation of the hot air furnace.
