Ceramic fiber is a fibrous lightweight refractory material, mainly composed of aluminum silicate. It can be divided into two categories based on its mineral composition: glassy fiber and polycrystalline fiber. Glass fiber is an amorphous solid fiber formed by the cooling of a molten liquid state; Polycrystalline fibers are mostly formed by colloidal injection method (or spinning method) and calcined at high temperatures.

　　Refractory materials

　　Ceramic fibers are widely used as insulation and high-temperature resistant materials in various types of thermal kilns. Due to their significantly lower capacity than other refractory materials, their heat storage is very small and their insulation effect is obvious. As lining materials, they can greatly reduce energy consumption in thermal kilns, bringing a revolution in energy conservation for thermal kilns. On the other hand, its application technology and methods have also brought about a revolution in the masonry of thermal kilns.

　　1. Current usage status

　　Ceramic fibers first appeared in 1941, when Bab Wilcox Company in the United States used natural kaolin to melt and blow into fibers in an electric arc furnace. In the late 1940s, two American companies produced a series of aluminum silicate fibers and first applied them in the aviation industry; In the 1960s, the United States developed various ceramic fiber products and used them for industrial kiln wall lining. In the 1970s, ceramic fibers began to be produced and used in China, and their application technology was rapidly promoted in the 1980s. However, the main temperature range used was below 1000 ℃, and the application technology was relatively simple and backward. After entering the 1990s, with the promotion and application of zirconium containing fibers and polycrystalline alumina fibers, the usage temperature increased to 1000 ℃~1400 ℃. However, due to product quality defects and outdated application technology, the application fields and methods were limited. For example, polycrystalline alumina fibers cannot be made into fiber blankets, and product specifications mainly focus on loose cotton and fiber blocks. Although the insulation temperature of household appliances has increased, the strength is poor, limiting the scope of use and shortening the service life.

　　Zirconium containing fiber is a widely used and low-cost aluminum silicate fiber produced by the melting method, which can be widely used as a hot surface full fiber lining for various thermal kilns. Currently, the quality and application development of domestic products in this area are relatively backward. Chromium containing fibers have emerged abroad, with higher usage temperatures than zirconium containing fibers, and there is no report on this in China.

　　2. Type and purpose

　　The main varieties of ceramic fibers include: ordinary aluminum silicate fibers, high alumina aluminum silicate fibers, aluminum silicate fibers (containing Cr2O3, ZrO2 or B2O3), polycrystalline alumina fibers, and polycrystalline mullite fibers. In recent years, some new ceramic fiber varieties have been successfully developed (or are currently being developed) abroad, such as magnesium olivine fibers, ceramic fibers (SiO2 CaO MgO series and Al2O3 CaO series), etc. The main forms of ceramic fiber products include: ceramic fiber cotton, felt, blanket, module, paper, cloth, belt, rope, etc.

　　Ceramic fiber blanket (fiber module): It is often made of spun long fibers using self melting, continuous melting, and continuous casting production processes. The fibers are interwoven by double-sided needling, and can be directly used as a flame hot surface. It integrates fire resistance, insulation, and insulation, and can be used in neutral, oxidizing, and partial reducing atmospheres for a long time, still maintaining good strength and toughness. The fiber module made of this fiber blanket does not contain binders and has good thermal stability. It is widely used in insulation and heat resistance fields such as petrochemical, metallurgy, and power.

　　Ceramic fiber board: made of ceramic fibers, binders, and additives through processes such as pulping, molding, curing, and drying. Ceramic fiber board has good flexibility, easy cutting, and high strength. It is a new type of energy-saving and environmental protection product with low thermal conductivity and low heat storage. It is widely used as a backing for various heating equipment walls, roofs, and other parts, and is a heavy refractory material.

　　Ceramic fiber cloth and tape: mainly used for fire doors, industrial kiln insulation, and insulation of high-temperature pipelines and containers.

　　Ceramic fiber rope: mainly used for expansion joints in various industrial kilns, winding insulation of high-temperature pipelines, and insulation of steel structure connections.