Mullite bricks used for hot air ducts are refractory products primarily composed of mullite as the main crystal phase. They are made by using mullite as the main raw material, along with refractory clay, kaolin, zircon sand, and additives. The production process involves mixing, shaping, drying, and high-temperature firing to obtain mullite refractory bricks.

1.Why are mullite bricks used for hot air ducts?
The typical lining structure of a hot air duct includes refractory spray coating, refractory fibers, lightweight insulation bricks, and working layer refractory bricks. However, after being put into operation, this structure often experiences cracking, spalling, and thermal deformation, which severely affects the performance of the hot air duct. In order to address this issue, Ruiwo has developed a special type of mullite brick specifically for hot air ducts, replacing conventional refractory bricks. Mullite bricks exhibit a certain degree of toughness and abrasion resistance at high temperatures, and they can resist the permeation of carbon monoxide atmosphere, making them the preferred choice for the working layer of hot air ducts.

2.Characteristics of mullite bricks used for hot air ducts:
High load softening temperature
Good thermal shock resistance
Excellent thermal stress resistance
Good abrasion and erosion resistance

3.Applications of mullite bricks in hot air ducts:
Mullite bricks are used in various parts of the lining construction of hot air ducts, including suspended sections and openings, vertical ducts, high-temperature straight sections, circumferential areas, and temperature-stable sections. Different grades of mullite bricks are used in different regions of the duct.

4.Considerations for using mullite bricks with toughness in hot air ducts:

(1)To achieve better performance, precast membrane with a combination of mullite bricks is used during the construction of hot air ducts.

(2)Suitable refractory mud is used in conjunction with mullite bricks during the lining construction.

(3)Different areas require mullite refractory bricks of corresponding grades, and mixing different grades of mullite bricks is prohibited.

(4)Mullite bricks with non-compliant dimensions should not be used.