Refractory materials are non-metallic materials or products whose chemical and physical properties allow them to be used at high temperatures. ISO defines it as a material or product with a fire resistance of at least 1580°C.
A million years ago, the land of China left traces of the use of fire. During the Yangshao culture period about 7,000 years ago, our ancestors burned pottery. During the Spring and Autumn period more than 2,500 years ago, cast iron began to be smelted. During the Eastern Han Dynasty (25-220 AD), clay refractory materials were used to make ceramic bodies for furnaces and crucibles for melting metals. The rapid development of refractories is accompanied by the development of metal smelting. With the rapid development of blast iron technology before and after the industrial revolution, refractory materials ushered in the first major technological advance and began large-scale industrial applications.
Refractory materials are widely used in metallurgy, building materials, chemical industry, petroleum industry, national defense and other industries, and are most used in high-temperature metallurgy. In addition to being used as furnace lining, refractory materials also play a role in thermal insulation, energy saving and environmental protection.
Usually the basic requirements for refractory materials are:
1. High temperature performance: The working temperature of modern industrial furnaces is usually 1000-1800℃, so the refractory material is required not to soften at this temperature.
2. Volume Stability at High Temperature: When a refractory material is used at high temperature, the volume changes due to physical and chemical reactions within the material. If the volume change exceeds a certain range, the structure of the furnace body will be damaged, so the refractory material must have good volume stability.