Routine Maintenance of Several Types of Refractory Fire Bricks

The refractory fire brick family includes core categories such as magnesia bricks, high-alumina bricks, and clay bricks, which are crucial for the lining of high-temperature kilns and boilers.

Magnesia bricks have outstanding alkali resistance, high-alumina bricks combine high-temperature resistance and strength, and clay bricks offer high cost-effectiveness. Although each has its own strengths, routine maintenance requires more meticulous attention compared to ordinary cement bricks. Slight negligence can lead to peeling and cracking in all types of refractory fire bricks. The following targeted maintenance details must be implemented.

Basic Inspection: Building the First Line of Defense for Safety

1. Regular Inspections, Focusing on Vulnerable Areas

Before starting the machine each day, a categorized inspection should be conducted according to brick type. High-alumina bricks are commonly used in the core high-temperature zone of the kiln; focus on checking for brittleness and pulverization. Magnesia bricks are susceptible to acidic corrosion; check for white spots on the surface. Clay bricks have weak crack resistance; pay attention to whether cracks are appearing at the edges and corners.

Areas under stress, such as kiln corners and around the furnace door, are more prone to problems. During inspection, compare the bricks with adjacent insulating bricks; if the brick’s color darkens abnormally or gaps appear at joints, mark them immediately.

Tap the bricks weekly with a small hammer. A clear, crisp sound indicates they are in good condition; a dull sound suggests internal hollowness, requiring immediate attention.

2. Monitor temperature and avoid thermal shock.

Different types of refractory fire bricks have different thermal shock resistance; temperature control must be adjusted according to the brick type.

Clay bricks have the worst resistance to rapid heating and cooling; the temperature increase should not exceed 80°C per hour. High-alumina bricks can be heated up to 100°C. While magnesia bricks are heat-resistant, they will still crack if cooled suddenly. When cooling down, do not turn off the heat source directly; cool gradually: clay bricks should be cooled to below 150°C and then allowed to cool naturally; magnesia and high-alumina bricks can be cooled up to 200°C.

Simultaneously check the temperature measuring instruments to prevent localized overheating that could burn the bricks.

Cleaning and Maintenance: Extending the Service Life of Bricks

1. Timely Removal of Adhesives to Prevent Corrosion

After kiln use, clean any adhesives according to the characteristics of the bricks.

If the ash on the surface of high-alumina bricks contains acidic components, long-term adhesion will reduce strength. For magnesia bricks, special attention should be paid to removing alkaline residues to avoid chemical reactions. Molten material on the surface of clay bricks should be scraped off promptly to prevent clogging of pores. Use a special steel scraper to gently scrape; do not use sharp tools to scratch the brick surface.

For tightly bonded adhesives, soften them with warm water before removal, especially for brittle clay bricks; do not use excessive force.

2. Proper Repair to Prevent Potential Exacerbation

When small cracks are found, select the appropriate repair material according to the material: use high-alumina repair material for high-alumina bricks, magnesia material for magnesia bricks, and clay-based repair material for clay bricks, ensuring material compatibility.

If a brick peels off in a localized area, replace it with a new brick of the same type, ensuring a tight fit with the original brick. Fill the gaps with refractory mortar of the appropriate material. Damaged refractory fire bricks that need to be replaced, especially magnesia and high-alumina bricks which contain special components, must be stored centrally. While clay bricks have a simpler composition, they cannot be discarded as easily as cement bricks to avoid contamination.

Maintenance of magnesia, high-alumina, and clay bricks requires meticulous attention. “Brick-specific” maintenance is key to the long-term operation of equipment.

If you encounter difficulties in preventing cracking of clay bricks, acid corrosion of magnesia bricks, or brittleness of high-alumina bricks, or have any questions about brick inspection and repair, please feel free to contact us.

We have a professional refractory fire brick maintenance team that can provide customized solutions to help you accurately avoid potential hazards, ensuring that every refractory fire brick reaches its maximum value and building a solid barrier for your production safety!