Good thermal stability at high temperatures refractory heavy weight mullite brick use for blast furnace

Good liquid glass erosion scour resistance refractory mullite brick use for glass furnace of the cover plate

Mullite electric fused brick is a kind of aluminum-silicon refractory products which are cast into a certain shape after being melted at high temperature and take mullite as the main crystalline phase.Since the main crystalline phase of mullite brick is mullite, the properties of mullite brick are mainly made of mullite. Therefore, the refractoriness of mullite brick is around 1850℃, with high softening temperature under load, low creep rate at high temperature, good thermal shock resistance and acid slag erosion resistance.
Mullite brick should not contact with alkali above 1450℃, otherwise it will decompose mullite.Under the reducing atmosphere above 1370℃, mullite will also decompose, and part of SiO2 will turn into gaseous SiO and leave the brick.Mullite decomposes at temperatures above 1650 ° C, even at low partial oxygen pressures, rather than in a reducing atmosphere.

Mullite brick, as a common brick in glass melting furnace, can be used in many parts of glass melting furnace. The following is the application of mullite brick in different parts of glass melting furnace.
1. Front gable
The front wall of the glass melting furnace is close to the compound material area. Due to the large temperature fluctuation, more raw material dust and relatively harsh conditions in this area, the sintered mullite brick has good resistance to rapid cooling and rapid heat as well as good resistance to compound material dust erosion.Therefore, resintered fused mullite brick can be designed and used in the hanging wall and the wing wall of the feeding port.
2, the neck
The neck is generally designed with water bag and agitator. When the equipment is maintained, the neck space will produce a large temperature difference, and the sintered mullite brick is a better design choice in this place.
3. Upper wall of small furnace and regenerator
Small furnace using zirconium fused corundum brick is the best design choice, because of the mullite brick, especially with fused mullite as raw material of mullite brick, also has a good batch and alkali vapor erosion resistance, and then sintered fused mullite brick may be used on small furnace, can last at least a few of small furnace use, to improve the operating environment of small furnace body and reduce the cost of the parts.Similarly, resintered fused mullite bricks can also be used in the upper wall of the regenerator. Compared with alkaline bricks, mullite bricks have lower thermal conductivity and expansion coefficient, which can reduce the expansion deformation tendency of the kiln body and reduce the heat dissipation and insulation cost of the kiln body.
4, Coal-fired glass melting kiln small furnace crown and tongue crown
As is known to all, the service life of gas kiln bottlenecks in the small furnace parts, the traditional design of the silica used equipped with tongue self-closed fused zirconium corundum brick, because the temperature is below 1450 ℃, using silica brick in this site and not the best choice, the erosion area, using good erosion resistance of mullite brick, can prolong the service life of each part of the body.In addition, tongue-walling uses fused zirconium corundum brick, which may be a better choice for resintered fused mullite brick due to its poor thermal shock stability.
5. Gas regenerator lattice
At present, the designed grid of gas regenerator adopts clay brick, whose general service cycle is 3~4 years, which cannot meet the demand of longer and longer kiln age. Replacinggrid brick will not only cause heavy labor intensity, but also cause damage to other parts of kiln.A certain amount of sintered mullite bricks at the top of the gas lattice can prolong the service life of the furnace.
6, grate crown and bottom lattice body
The longer the kiln is, the more frequent the operation of the regenerator will be. The brickwork and brickwork will experience more thermal shock. The good thermal shock performance and corrosion resistance of sintered mullite brick can improve the service life of this part.
7. Operation hole
Mullite brick has good thermal shock stability and high temperature strength, and can be used in each operation hole of melting furnace, such as observation hole, spray gun hole, air supply hole and so on.
8. Grid under special conditions
The latest NOx emission standards have prompted more and more glass manufacturers to improve their production processes and adopt reducing atmosphere operation to reduce NOx content, which will lead to the increase of alkali vapor (NaOH) concentration in the flue gas and aggravate the lattice erosion.The resintered fused mullite brick has good resistance to alkali vapor erosion and can be used as a lattice configuration under such conditions.
9, special glass kiln configuration for use
1) sodium silicate furnace
The main components of sodium silicate compound are soda soda and silica sand, of which the weight percentage of soda soda as flux varies according to the modulus of sodium silicate, accounting for about 25 ~ 45%.Compared to other glass products, has a lower melting temperature and the batch of sodium silicate is a higher concentration of alkali vapor in flue gas, the current domestic water glass furnace parts is used silica brick and high-alumina brick, is silica brick and high-alumina brick has certain advantages in price, but the universal water glass furnace service life is short, energy consumption is on the high side.Comprehensive analysis shows that it is economical to use sintered mullite brick in sodium silicate kiln.
2) Oxygen glass melting furnace
The all-oxygen glass melting furnace uses oxygen to replace the traditional air combustion combustion mode, reducing a large amount of N2 in the flue gas and reducing the amount of smoke, which is convenient for energy saving and consumption reduction. However, the alkali vapor concentration and water vapor concentration in the flue gas are also greatly increased, and the traditional silica brickwork has been replaced by electric fused zirconium corunum brick and electric fused αβ brick.Due to the problems of high price and difficult construction of electric fused bricks, there are alternatives to sintered materials such as calcium-free silicon bricks produced by RHI and magnesia-alumina spinel bricks produced by DSF.Sefpro's resintered electrically fused mullite bricks have been used successfully in fiberglass furnaces for many years, and perhaps sintered mullite bricks can be used in all oxygen furnaces for other glass products as well.