The use of BIO ceramic fibers has become an extraordinary application for a wide range of medium and high temperature industrial processes (up to 1200ºC). However, they are limited to other very demanding applications where a very high temperature resistance is required, such as, for example: reheating processes, forging, ceramic kilns, etc… where temperatures of 1300ºC and 1400ºC are clearly exceeded in vaults.
In these furnaces, traditional BIO ceramic fibers are not valid, as they are limited by their maximum use temperature and the shrinkage they undergo over time. Many times, we see kilns with ceramic fiber modules that when they cool down, they contract and it is necessary to finish with fiber those openings that have been left. See photo.
The solution involves the use of high-temperature polycrystalline fibers, either mullite and/or alumina based, which withstand temperatures up to 1700ºC. They are manufactured in a very special way, with fibers of very thick diameters and above the breathable limit. They are therefore suitable for use with maximum safety in their installation.
INSERTEC in its high-temperature (1350ºC) ceramic firing kiln uses a lining made of 1600ºC polycrystalline fiber with obvious advantages, especially associated with lower energy loss and durability of the kiln walls and refractory vault.
The properties that these high temperature ceramic fibers have are:
- Minimal shrinkage. Very dimensionally stable over time.
- Low level of internal nodules.
- Low thermal conductivity.
- Low heat storage
- High resistance to hot gases.
- Excellent resistance to thermal shock.
- Excellent chemical stability
- High corrosion resistance
Typical high temperature applications:
- Replacement of water-cooled panels, supports, etc. in rotary hearth, walking beam furnaces.
- Heat treatment and forging furnace vaults.
- Lining of sintering chambers for ceramic parts.
The main problem with these fibers is, a priori, their high price. However, it is necessary to make the numbers, because many times, cheap is much more expensive.