CCEWOOL® ceramic fiber explanation

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Alumina silicate refractory fibers’ issues easily occurred in kilns for brick tile

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Why do we use of lightweight and high performance fire - resistant

fiber as a thermal insulation lining for brick kiln furnace?

• Can reduce 40% of fuel consumption

and shorten 35% of firing period, which could increase firing efficiency of brick and tile products effectively.

•It means a lot for improving quality of brick and tile product •energy-saving •cost-reducing.

Do you know

• Any problems when using them？

• In recent years, The fibrous structure at the top of the wicket of annular kiln and kiln, tunnel kiln, kiln top is widely used in all sorts of furnace type.

• But it is found that refractory fiber in use after a period of time is possible to occur pulverization, contraction and oxidation, fibers fall off, and Installation does not reach the designated position, etc.

The first problem

• High temperature makes alumina silicate refractory fibers pulverized.

• Analyzed from the thermodynamics, due to that any material has characteristics of making its surface be the lowest, so under the condition of certain thermodynamics, the total surface area of refractory fiber tends to be minimum.

• Tiny grain or particle will gradually condense into big grain or particle, and the unit cell grows as the temperature increases to lead to deterioration in their resistance to thermal shock resistance.

• Due to the refractory fiber's long-term work under high temperature, refractory fiber's fine crystal will bear high temperature for a long time, it will accordingly grow up gradually. Fiber surface is becoming rough, and crack appeared.

• When the crystal grew up to the fiber diameter, the fiber strength will drop to limitation that cannot work under internal pressure, thus to make the fiber breakage pulverization, which is the main reason of refractory fiber's broken.

The second problem

• Alkali, sulfur and other harmful gases cause erosion of aluminum silicate refractory fibers and oxidation shrinkage.

• Air component of brick firing furnace is quite complex, including both the fuel vapor harmful gases produced by combustion and water evaporation produced by body, as well as alkali metal ions existing in the raw materials. Since refractory fiber has a very large surface area, when the water vapor presents in the air, refractory fibers will absorb a lot of moisture.

• At the same time, the carbon dioxide and silicon dioxide in furnace medium can dissolve in water, forming weak acid. Weak acid and alkali ion fiber can take replacement reaction, thereby undermining the fiber structure, and it will lead to the fibers’ erosion and deterioration in long-term use.

• Alkali metal ions and aluminum silicate refractory fibers can react and result in feldspar, destroying the fiber’s network structure. Under reducing atmosphere, fiber crystallization will accelerate, reducing the fiber’s life.

• These harmful gases and substances will react with refractory fiber, corroding refractory fiber, destructing of its original structure, which caused refractory fiber’s pulverization, shrinkage and breakage. It is also one of the important reasons accounting for the usage life of furnace.

The third problem• air scour off the fibers

• In the long-term effects of high temperature, the grains of ceramic fibers in brick firing kiln grow brittle, so the tensile strength decreases dramatically. After chalking fiber at high speed airflow erosion, powder particles are constantly blew, flowing along with the media.

• As the fibers are constantly being washed off, kiln wall's thickness decreases, so the insulation effect deteriorates, kiln lining heat increased, which make the heat consumption increases, thus greatly affecting the thermal efficiency of brick kilns.

• This situation not only pollute the environment, but also reduce the brick kiln's life.

The fourth problem

• displaced installation and the wrong material selection

• At present, alumina silicate refractory fibers used in the brick kiln, is usually divided into ordinary type, standard, high-purity type, and high-alumina type.

• CCEWOOL® ceramic fiber also launched a high-zirconium-type. Selection of refractory fiber should according to characteristics of local raw materials. When alkali and sulfur content are high in raw materials, the furnace should use composition fire-resistant fiber.

• On the refractory fiber installation, a lot of fire-resistant fiber manufacturers generally used the anchor hook to secure ceramic fiber modules.

• As we all know, such fixed pattern did not completely secure the block, and the refractory fiber module completely rely on their expansion after releasing package. If not completely anchor position, will inevitably lead to mutual swim between the module and secure the module completely, it will lead to move between blocks, with the high-temperature contraction of the gap between the modules will eventually make anchor oxidation and the module's off, causing serious damage to the furnace.

• Some furnace company in order to reduce the cost of construction of the furnace, they even don't lay steel panel on steel structure. The Alumina silicate refractory fibers loses steel panel's care, the consequences can be imagined.

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