2013年7月23日星期二

Refractory ceramic fiber performance and development prospects

In recent years, high-temperature ceramic fiber kiln firing the application prospect of expanding to all kinds of ceramic fiber insulation products to good effect, easy to use, especially in small storage and other features, widely used in all kinds of kilns , which greatly shows high energy efficiency.
(A) variety and performance: ceramic refractory fibers most important indicator is the fiber diameter and thermal stability. Commonly used in ceramic industry is Al2O3SiO2 fiber, according to the level of Al2O3 content into different scope of use, but also to introduce them to improve their Cr2O3 refractory material with antioxidant properties. Generally high alumina content, low content of iron and other impurities fiber product was pure white, chromium oxide fibers were introduced Pins milk yellow color tone. The average diameter of the ceramic fibers of 2-4 microns. Fiber fineness, low density, low thermal conductivity by use of high temperature. If crude fiber, high density use is not ideal. The thermal stability index fiber is more important. Al2O3-SiO2 fiber variety of products at 1260 ℃ linear shrinkage between the range of 35-88%. Also directly affects the amount of shrinkage thermal stability.
Low thermal conductivity of the fiber density, light weight, the design and construction of the furnace are used when lighter steel support structure, so that the development of ceramic kiln into the "kiln lightweight" era. Fiber regenerative small, adapt to rapid heating and cooling firing mode. Flexible fibers can be processed into products with recesses or openings, and has good resistance to mechanical vibration and shocks, good chemical stability, these advantages is the development of a new furnace, and spread to ceramic technology, industry have an important role in promoting development.
Currently ceramic fiber products are: carpets, blankets, blocks, bulk fiber, fiber paper and vacuum forming of various products, the working range is generally 871-1427 ℃, special circumstances may be short-term temperatures above the temperature limit is used.
(2) masonry methods and precautions: refractory fiber felt for furnace lining can greatly improve energy efficiency. General use of synthetic organic binder so that the fiber volume tubular or sheet-shaped fabric. Lightweight high temperature furnace brick masonry wall, the available refractory ceramic fiber blanket paste into the lining, after firing, the fiber mat or plate form a certain rigidity and ability to have satisfactory reply, the cooling time can play back so that the seam taut.
Masonry fibers are usually two ways: First, the rugs applicator layer by layer, and then the bolt lever riveted together, usually in the 1222 ℃ temperature below with metal bolt rod, 1223 ℃ above using ceramic quality rivet. Side by side with the bulk heat resistant fiber and cement filling. Riveting quality ceramic pieces can prevent deposition of carbon fiber deterioration. The second method is the use of prefabricated assembly, which uses rugs stacked preform or the rugs with a wide 305mm folded accordion style preform. In comparison, the latter due to the hot surface next to the furnace shell are the same materials, energy efficient, but the cost is higher.
Temperature, the fiber preform required masonry seam formed elastic fiber inlay. Prefabricated assembly, easy installation, quick and easy maintenance, simply replace the damaged part down.
On the thermal efficiency, the layers of the applicator way better than prefabricated assembly. Because the former fiber direction perpendicular to the heat, the stack assembly of prefabricated shaped fiber direction parallel to the heat flow difference between the two is about 20-40% of the heat conductivity, such as accordion-like assembly of the preform folded in between its fiber direction parallel and perpendicular to the heat flow.
(3) Prospect: Due to rising energy prices, fuel costs will become a bottleneck in the development of ceramics curb, saving even more important. People are increasingly concerned about the heat loss of the furnace, some directly affixed to the original surface layer of refractory lining refractory ceramic fibers in order to improve thermal efficiency. In the kiln must be affixed to the wall before the apparent cracks or spalling parts repaired. But insulating firebrick and refractory fiber can not be indiscriminate. So far, such as basic oxygen steelmaking furnaces, cement rotary kiln lining, serious erosion due to high temperature chemistry are temporarily unavailable fiber as lining.
For continuous heating equipment, such as ceramic tunnel kiln, have long been used as a refractory ceramic fiber lining continuous heating equipment, according to the information reported, quickly push board kiln and tunnel kiln refractory ceramic fibers used in energy-saving effect is very significant. In particular, ultra high temperature heating, such as firing temperature 1538 ℃ -1649 ℃ kiln, the use of the best energy-resistant fiber.
At present, Europe and Japan ceramic kiln equipment used ceramic fiber lining. Gas-fired tunnel kiln recently Japan will be decomposed into sub-sections such as car manufacturing structure, and then delivered to the construction site porcelain factory assembled, all this is due to the use of ceramic fiber material, saving furnace costs, easier sake. Modified from the material aspects of ceramic fiber products to promote energy efficiency study is also underway.

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