Refractory ceramic fibers are made from clay clinker (pyroxene) with low impurity content as raw materials, which are melted, blown or spun into fibers at a high temperature of 1800-2000 ℃. The Al2O3 content in the fibers is about 45%, and the long-term use temperature does not exceed 1000 ℃.
High purity aluminum silicate refractory fiber uses industrial alumina and high-purity silica sand or quartz sand as raw materials, and can also add a small amount of B2O3 or ZrO2 as additives. After mixing ingredients, melt blowing or spinning, the fiber produced contains about 50% Al2O3, with Al2O3+SiO2>99%. The maximum usage temperature is 1260 ℃, and the long-term usage temperature is about 1100 ℃.
Chromium containing aluminum silicate refractory fibers are made from industrial alumina, silica powder, and chromium oxide as raw materials. The ingredients are 40% to 60% of silica powder, 40% to 55% of industrial alumina, and 3% to 6% of chromium oxide. They are melted, blown, or spun into fibers, with a maximum usage temperature of 1400 ℃ and a long-term usage temperature of 1150 to 1200 ℃.
High alumina refractory fibers are mainly made of industrial alumina and high-purity silica as raw materials. The batch is melted and blown or spun into fibers to obtain high-purity glassy aluminum silicate refractory fibers with an alumina content of over 58%. The maximum operating temperature is 1400 ℃, and the long-term operating temperature is 1200 ℃.
Mullite refractory fibers are made from aluminum chloride, metal aluminum powder, silica sol, glacial acetic acid, and various organic additives. Through processes such as gelation, fibrosis, and heat treatment, polycrystalline fibers with Al2O3 content ranging from 72% to 80% are produced. The main component is mullite, and the operating temperature is between 1300-1500 ℃.
Alumina refractory fibers are made from raw materials such as aluminum chloride, metallic aluminum powder, silica sol, glacial acetic acid, and various organic additives. Through processes such as gelation, fibrosis, and heat treatment, polycrystalline fibers with Al2O3 content of about 95% and SiO2 content of about 5% are produced. The main mineral components of the fibers are θ- Al2O3 or α- Al2O3, operating at temperatures ranging from 1400 to 1600 ℃.
Zirconia refractory fibers are made from raw materials such as zirconium acetate, zirconium oxychloride, YCl3, MgCl2, CaCl2, etc., and undergo processes such as gelation, fibrosis, and heat treatment to produce refractory fibers with a main component of ZrO2 (including stabilizer) greater than 98%. The service temperature is 1600 ℃.
Classification is usually based on the maximum allowable temperature for the use of refractory fibers. The method is to heat and insulate the refractory fiber sample for 24 hours, and the temperature at which the linear shrinkage is close to or less than 2.5% is used as the classification temperature. The actual maximum allowable long-term use temperature should be lower than the classification temperature. In an oxidizing atmosphere, the maximum long-term use temperature should be 100-150 ℃ lower than the classification temperature. In a reducing atmosphere, it should be 200-250 ℃ lower, and in a vacuum atmosphere, it should be 400-450 ℃ lower.