In recent years, the application prospect of ceramic fiber in high-temperature firing kiln is expanding day by day. All kinds of products made of ceramic fiber have the advantages of good heat insulation effect, easy to use and small heat storage in particular, and are commonly used in various kilns In, greatly show the high energy efficiency.
(1) Variety and performance: The most important index of ceramic refractory fiber is the fiber diameter and thermal stability. Ceramic industry is commonly used Al2O3SiO2 fiber, according to the level of Al2O3 content is divided into different areas of use, but also the introduction of Cr2O3 material in order to improve its fire-resistant and antioxidant properties. General high alumina content, iron oxide and other impurities in low-purity fiber products were pure white, the introduction of chromium oxide fibers were pin yellow milk color. The average diameter of ceramic fibers is 24 microns. Fine fibers, low density, low thermal conductivity, high temperature. If the fiber thick, high density, the effect is not satisfactory. Fiber thermal stability index is more important. Al 2 O 3 -SiO 2 fibers ranged from 3588% at 1260 ° C for various products. Shrinkage also has a direct impact on thermal stability.
Due to the low thermal conductivity, low density and light weight of the fiber, the lighter steel frame support structure is adopted in the design and construction of the kiln, so that the development of the ceramic kiln has entered the era of lightweight kiln. Small fiber heat storage, to adapt to rapid heating, cooling and firing methods. Flexible fibers can be processed into a grooved or open products, and has good resistance to mechanical shock and impact, chemical stability is also better, these advantages for the development of new kilns, and spread to the ceramic technology, the industry Development has an important role in promoting. At present, ceramic fiber products are: felt, blanket, block, bulk fiber, fiber paper and vacuum forming a variety of products, the working range is generally 8711427 ℃, under special circumstances can be short-term use above the extreme temperature.
(2) masonry methods and precautions: Refractory fiber mat, suitable for furnace lining can greatly improve energy efficiency. Organic binders are typically used to wind the fibers into a tubular or sheet-like fabric. After the inner wall of the furnace is built with high-temperature light-weight refractory bricks, it can be lined with ceramic fiber refractory felts. After firing, the fibrous felts or slabs form a certain rigidity with satisfactory resilience and can rebound when cooled Tighten the seams.
There are usually two methods for masonry fiber: one is to apply the carpet layer by layer and the other by riveting. The temperature is below 1222 ℃ and the temperature is above 1223 ℃. Ceramic riveting is adopted above 1223 ℃. One end of the hot side with bulk fiber and heat-resistant cement filled. Ceramic riveting pieces also prevent fiber deterioration due to carbon deposition. The second method uses prefabricated assemblies, prefabricated with carpet or folded into accordion preforms with 305 mm wide carpet. Compared with the latter, the latter is the same material close to the furnace shell to the hot surface, energy-efficient, but the cost is higher. When the temperature rises, the seams formed by the fiber preform masonry need to have a stretchable fiber inlaid. Prefabricated assemblies are easy to install, quick and easy to service, just replace the damaged parts.
In terms of thermal efficiency, layers of application are significantly better than prefabricated assemblies. Because the fiber direction of the former is perpendicular to the heat flow, the direction of the fiber of the prefabricated assembly is parallel to the heat flow, and the difference between the two is about 2040%. For example, accordion folded prefabricated assembly is in between The fiber orientation is both parallel and perpendicular to the heat flow.
(3) Prospect of Development: Due to rising energy prices, fuel costs will become a bottleneck in curbing the development of the ceramics industry. Energy conservation will become even more important. People are getting more and more concerned about the heat loss of the kiln, and some directly attach a layer of refractory ceramic fiber on the surface of the original refractory lining to improve thermal efficiency. It is necessary to repair obviously cracked or peeled parts of the kiln wall before affixing. However, insulation refractory bricks and refractory fibers can not be arbitrary abuse. So far, such as basic oxygen steel furnace, cement rotary kiln lining, due to the high temperature chemical erosion, are temporarily unable to use fiber lining.
For continuous heating equipment such as ceramic tunnel kilns, refractory ceramic fibers have long been used as linings for continuous heating equipment. According to the information reported, the use of refractory ceramic fibers in fast push kiln and tunnel kiln energy saving effect is significant. Especially the ultra-high temperature heating, such as firing temperature at 1538 ℃ 1649 ℃ kiln, the use of fire-resistant fiber, the best energy-saving effect.
At present, ceramic kiln equipment in Europe, the United States and Japan all use ceramic fiber lining. Not long ago Japan decomposed the gas tunnel kiln into sectional structures such as the car body structure and delivered it to the construction site of the porcelain factory for assembly. All this is due to the ceramic fiber material, which greatly saved the cost of the kiln and made it easier. Research on the energy saving effect of ceramic fiber products from material modification is also underway.