Refractory fiber is a fibrous refractory material and an efficient thermal insulation material. It has the characteristics of ordinary fibers (such as softness, high strength, etc.) and can be processed into various papers, belts, cords, felts, blankets, etc. It also has high temperature resistance, corrosion resistance and anti-oxidation properties that ordinary fibers do not have, and overcomes the problem of It reduces the brittleness of general refractory materials. At the same time, it has a very significant energy saving effect. As a refractory and heat-insulating material, it has been widely used in metallurgy, chemical industry, machinery, building materials, shipbuilding, aviation, aerospace and other industrial sectors. China began to trial-produce aluminum silicate refractory fibers in the early 1970s and successfully used them in industrial furnaces. In the 1980s, great progress was made in basic fiber theory, new product development, and promotion and application. Three types of polycrystalline refractory fibers, Al2O372%, Al2O380%, and Al2O395%, have been successfully developed. ZrO2 polycrystalline fiber was also successfully developed in the laboratory.

Refractory fibers are divided into two categories: amorphous (glassy state) and polycrystalline (crystalline state). Amorphous refractory fibers include aluminum silicate, high-purity aluminum silicate, chromium-containing aluminum silicate and high-aluminum refractory fibers. Polycrystalline refractory fibers include mullite fiber, alumina fiber and zirconia fiber. There are also classifications based on the maximum allowable use temperature of refractory fibers.

Aluminum silicate refractory fiber uses clay clinker (charred gemstone) with low impurity content as raw material, and is melted, blown or spun into fibers at a high temperature of 1800 to 2000°C. The Al2O3 content in the fiber is about 45%, and the long-term use temperature is not stable. over 1000℃.

High-purity aluminum silicate refractory fiber is made of industrial alumina and high-purity silica sand or quartz sand as raw materials. A small amount of B2O3 or ZrO2 can also be added as additives. It is made by mixing ingredients, melt blowing or spinning into fibers. The fiber contains about 50% Al2O3, Al2O3+SiO2 > 99%, the maximum operating temperature is 1260°C, and the long-term operating temperature is about 1100°C.

Chromium-containing aluminum silicate refractory fiber uses industrial alumina, silica powder and chromium oxide as raw materials. It is formulated with 40% to 60% silica powder, 40% to 55% industrial alumina, and 3% to 6% chromium oxide. It is melt sprayed Blown or spun into fibers, the maximum operating temperature is 1400℃, and the long-term operating temperature is 1150~1200℃.

High-aluminum refractory fiber uses industrial alumina and high-purity silica as the main raw materials. The batch materials are melt-blown or spun into fibers to obtain high-purity glassy aluminum silicate refractory fiber with an alumina content of more than 58%. The maximum operating temperature is 1400℃, and the long-term operating temperature is 1200℃.

Mullite refractory fiber uses aluminum chloride, metal aluminum powder, silica sol, glacial acetic acid and various organic additives as raw materials. Through processes such as gel making, fiberization and heat treatment, 72% to 80% polycrystalline Al2O3 is obtained. Fiber, whose main component is mullite, has a service temperature of 1300 to 1500°C.

Alumina refractory fiber uses aluminum chloride, metal aluminum powder, silica sol, glacial acetic acid and various organic additives as raw materials. After glue making, fiberization, heat treatment and other processes, it can produce about 95% Al2O3 and about 5% SiO2. Crystal fiber, its main mineral component is θ-Al2O3 or α-Al2O3, and its service temperature is 1400~1600℃.

Zirconia refractory fiber uses zirconium acetate, zirconium oxychloride, YCl3, MgCl2, CaCl2, etc. as raw materials. Through processes such as gel making, fiberization, and heat treatment, a refractory fiber whose main component is ZrO2 (including stabilizer) is obtained with more than 98% , using temperature 1600℃.