Description:
Mullite Refractory Bricks (also called mullite bricks) are made of synthetic fused mullite or sintered mullite, pressed by selected shaping processes, and fired in high temperature furnaces. Mullite refractory bricks offer high density, low porosity, good hot strength, and good slag resistance. Mullite bricks are preferred for high temperature, high load applications, such as at the hot end of regenerative chambers of glass melters, the superstructure of the furnace, and the arch of glass fiber melters, due to their excellent thermal properties, excellent strength at high temperature, great resistance to thermal shock, etc.
The mullite brick comprises the following chemical components in percentage by weight: 35 to 80 percent of Al2O3, 27 to 64 percent of SiO2, and 1 to 1.2 percent of Fe2O3. Mullite bricks are high-alumina refractories with mullite (3Al2O3·2SiO2) as the main crystal phase. Generally, the alumina content is between 70% and 80%. Mullite Refractory bricks have high refractoriness, which can reach above 1790℃. The starting temperature of load softening is 1600～1700℃. It has the good thermal shock resistance with cold crushing strength of 70～260MPa. There are two types of mullite refractories: sintered mullite bricks and fused mullite bricks. If the Al2O3 content in refractory brick is more than 80%, we call it as corundum mullite brick. If there is ZrO2 in the brick, we call it as Zircon Mullite Brick.
Mullite refractory bricks are widely used in glass furnaces, hot blast stove and etc.
Features of Mullite Refractory Bricks
Low levels of iron and other impurities
High mechanical intensity
High refractoriness, can contact with the flame directly, suitable for various atmosphere
High porosity, low volume density, low thermal conductivity
Good heat insulating performance and energy-efficient
Low creep rare at high temperature,good thermal shock stability
Chemical corrosion resistance
Long service life
Specifications.
Item / Types | JM-23 | JM-26 | JM-28 | JM-30 | JM-32 | XIJJM-35 | |
Chemical Composition (%) | Al2O3 | 40 | 55 | 65 | 70 | 75 | 80 |
SiO2 | 50 | 42 | 33 | 26 | 22 | 17 | |
Fe2O3 | 1 | 0.8 | 0.7 | 0.7 | 0.5 | 0.2 | |
TiO2 | 1.2 | 1.3 | 0.9 | 0.5 | 0.3 | 0.3 | |
CaO+ MgO | 0.7 | 0.6 | 0.2 | 0.3 | 0.2 | 0.2 | |
K2O+ Na2O | 1.3 | 1.1 | 0.8 | 0.2 | 0.1 | 0.1 | |
Classification temperature (ºC) | 1300 | 1420 | 1530 | 1550 | 1650 | 1700 | |
Bulk Density (g/cm3) | 0.6 | 0.8 | 0.9 | 1 | 1.1 | 1.1 | |
Cold Crushing Strength (MPa) | 1.2 | 1.8 | 2.5 | 3.3 | 3.5 | 3.5 | |
Modulus of rupture (MPa) | 1 | 1.7 | 2.3 | 3.1 | 3.2 | 3.2 | |
Permanent linear change (CT x24h)% | 0.6 | 0.6 | 0.8 | 0.9 | 1.01 | 1.01 | |
Thermal Expansion(%) @ 1000ºC | 0.5 | 0.52 | 0.52 | 0.53 | 0.6 | 0.7 | |
Thermal conductivity (W/m.k) | 350ºC | 0.18 | 0.27 | 0.32 | 0.38 | 0.45 | 0.49 |
400ºC | 0.2 | 0.29 | 0.34 | 0.4 | 0.45 | 0.5 | |
600ºC | 0.24 | 0.32 | 0.36 | 0.42 | 0.47 | 0.51 | |
Mullite refractory bricks should not be used for long-term use in high-alkaline slag and high water vapor content environments.
Dimensions of mullite refractory bricks
l 230 x 114 x 64 mm
l 230 x 114 x 76 mm
l Customized production for bricks with special dimension is available
Application
Furnace roof of hot blast stove
Furnace stack and bottom of blast furnace
Regenerative chamber of glass melting furnace
Ceramic high temperature furnace0