Difference between bonded mullite brick and Rebonded fused mullite brick

Sintered mullite brick and re-sintered fused mullite brick are two refractory materials made by different production processes. Their main differences lie in the production process, microstructure and performance characteristics.

Production process:
Sintered mullite brick: This type of brick is made by finely grinding and shaping natural raw materials (such as kaolin) and then sintering them at high temperatures. This process allows the components in the raw materials to react to form a mullite phase.
Re-sintered fused mullite brick: First, the raw materials are heated to a molten state in an electric arc furnace, which can remove impurities and promote the growth of mullite crystals. Subsequently, the melt is cooled and solidified, and then crushed, shaped, and sintered again to form the final product.

Microstructure:
Sintered mullite bricks usually have a relatively uniform microstructure, but may have more pores or glass phases.
Because the re-sintered fused mullite brick has undergone a melting process, its internal structure is more compact, the crystals are well developed, and it contains less pores and glass phases.

Performance characteristics:
Sintered mullite bricks have good refractoriness and are suitable for a variety of industrial kiln environments, but their mechanical strength and thermal shock resistance may be slightly lower than those of re-sintered fused products.
Re-sintered fused mullite bricks have better high-temperature strength, lower thermal expansion coefficient, excellent thermal shock resistance and chemical stability due to their higher purity and more optimized microstructure. This makes it more suitable for applications under extreme conditions, such as high temperature, strong corrosive environment, etc.
In summary, the choice of which type of mullite brick depends on factors such as specific application requirements, working temperature, and atmosphere conditions. For more stringent working environments, re-sintered fused mullite bricks may be a better choice; for conventional use scenarios, sintered mullite bricks with lower costs can be selected.