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Product overview
Mullite brick is a kind of high alumina refractory with mullite as the main crystal phase. Generally, its alumina content ranges is from 70% to 90%. In addition to mullite, the mineral composition of mullite brick with lower alumina content also contains a small amount of glass phase and quartzite, the mineral composition of mullite brick with higher alumina content also contains a small amount of corundum.
There are two kinds of mullite bricks: bond mullite bricks and fused mullite bricks. Bond mullite bricks is made of high alumina bauxite clinker, adding a small amount of clay or raw bauxite as a binder, by molding and firing. The fused mullite brick is made of high alumina bauxite, alumina powder and refractory clay with fine particles of charcoal or coke as reducing agent by Reduction electrofusion methods after molding . The crystallization of fused mullite brick is larger than that of bond mullite and its thermal shock resisitance is better than that of bond mullite brick.Their high temperature properties mainly depend on the content of alumina and the uniformity of the distribution of mullite phase and glass.
The high temperature creep resistance of Mullite brick is much better than the other high alumina bricks, including special grade high alumina brick. His some high temperature performance is as good as silica brick, magnesia brick and corundum brick, the thermal shock resistance is far superior to these products, the erosion resistance to acidity and low basicity slag is better than that of magnesia products, but not as good as corundum products. The main features are listed below.
Character:
Mullite brick has high refractoriness up to 1790℃. The starting temperature of load softening is 1600 ~ 1700℃, and cold crushing strength 70 ~ 260MPa. Good thermal shock resistance.
Specification
Item |
Index |
||
SM-77 |
SM-80 |
SM-90 |
|
Al2O3 /％ |
77 |
83.8 |
89.5 |
SiO2 /％ |
22 |
15.3 |
9.8 |
Fe2O3 /％ |
0.3 |
0.2 |
0.2 |
R2O/% |
0.25 |
0.25 |
0.25 |
Apparent Porosity/％ |
15.2 |
16 |
16.2 |
Bilk density g/cm3 |
2.7 |
2.75 |
2.95 |
Cold Crushing Strength /Mpa |
90 |
100 |
115 |
Hot modulus of rupture/Mpa (1400℃) |
8.4 |
10.0 |
1.03 |
0.2MPa Map Refractoriness Under Load/℃ |
＞1680 |
＞1700 |
＞1700 |
Linear Change （1600℃×3h）/％ |
0～0.2 |
0～0.15 |
0～0.1 |
High Thermal Shock Resistance/time (1100℃, water cooling) |
＞15 |
＞15 |
＞25 |
Thermal conductivity/W.(m.K)-1 |
3.48(1200℃) |
4.12(1200℃) |
|
Thermal Expansion/% (1300℃) |
0.68 |
0.74 |
0.86 |
Application
The mullite brick is mainly used for roof of hot blast furnace, the body and bottom of blast furnace, glass furnace re generator, ceramic sintering kiln, oil cracking system blind corner lining, etc.
The mullite brick are widely used in roof of hot blast furnace, the body and bottom of blast furnace, heating furnaces, ladles, crown, channel covers and re-generator Chambers glass furnace , heating furnaces used in mechanical industry, carbon black reaction furnaces used in petrochemical industry, and high-temperature firing kilns used in ceramic and refractory industry, etc.
Production line of bond refractory brick:
http://fr.refractories-bricks.com/
