Refractory bricks are a core material in high-temperature industrial kilns, and their service life directly affects production efficiency and safety.
Maintenance for different brick types needs to be tailored to material characteristics and operating conditions. Proper daily maintenance, adherence to usage guidelines, and regular inspections are essential to maximizing their high-temperature resistance and corrosion resistance.
Daily Use: Laying the Foundation for Maintenance
Temperature Control is Key
When starting up, follow the principle of “gradual heating.” Clay refractory bricks require at least 8 hours to heat from room temperature to 1000℃. High-alumina refractory bricks can be heated to 6 hours to avoid thermal shock cracking caused by excessive temperature differences.
When shutting down, cool down slowly. Never directly rinse the bricks inside the kiln with cold water, especially high-density bricks like corundum-mullite bricks, as sudden cooling can easily cause micro-cracks.
Reduce Media Corrosion
For magnesia-alumina spinel bricks used in the transition zone of cement kilns, it is necessary to control the alkali metal content in the raw materials and regularly clean the scale buildup inside the kiln to prevent alkali vapor from penetrating the bricks and causing spalling.
Special refractory bricks used in waste incinerators require timely removal of acidic waste residue from the furnace to prevent corrosion of the brick surface glaze.
Targeted Maintenance: Differentiated Operations for Different Brick Types
Clay Refractory Bricks
These bricks have high permeability, requiring regular checks of the joint seals. Gaps should be filled with high-temperature refractory mortar to prevent high-temperature gases from penetrating and eroding the brick body.
Avoid impacts from hard objects during daily use. Handle with care during transport. During periods of inactivity after installation, keep the furnace interior dry to prevent moisture absorption and pulverization.
High-Alumina Refractory Bricks
High-alumina bricks, commonly used in steelmaking furnaces, should avoid direct contact with molten metal. An anti-permeability coating can be applied to the brick surface.
If you notice localized wear during use, promptly repair the area with refractory spray—pay special attention to high-wear spots like furnace openings and corners.
Silicon Carbide Refractory Bricks
As the preferred brick type for high-temperature and highly corrosive environments, you must clean surface ash and deposits regularly to avoid ash buildup that hinders heat dissipation and causes localized overheating.
Welding or hammering on the brick surface is prohibited to prevent damage to its dense structure.
Magnesia-chrome Refractory Bricks
Commonly used in cement kiln firing zones, magnesia-chrome bricks require controlled kiln atmosphere to reduce the corrosive effects of reducing gases on the bricks.
If surface peeling occurs during use, replace the damaged bricks promptly to prevent crack expansion from affecting the overall structure.
Regular Inspection: Timely Identification of Potential Hazards
Daily Inspection
Observe the brick surface daily for cracks, peeling, corner chipping, etc., with a focus on checking the integrity of high-end brick types such as corundum bricks. Monitor the temperature distribution of the bricks with a thermometer; abnormally high localized temperatures may be a precursor to brick failure.
Regular Replacement
Replacement cycles should be determined based on operating conditions: clay refractory bricks generally last 1-2 years, high-alumina refractory bricks 2-3 years, and silicon carbide bricks 3-5 years. If brick wear exceeds 1/3 of its thickness, or if through-cracks appear, immediately stop the machine and replace the brick to avoid safety accidents.
Shutdown Maintenance
During furnace shutdown maintenance, thoroughly clean the furnace of waste slag and accumulated ash. Clean and seal the surfaces of intact bricks. During downtime, keep the furnace well-ventilated and dry to prevent the bricks from becoming damp and deteriorating, preparing them for the next use.
If you encounter difficulties in maintaining clay, high-alumina, or silicon carbide bricks. Or need customized maintenance solutions, or to purchase suitable brick types and maintenance materials, please feel free to contact us!
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