A refractory material retains its chemical and physical properties at high or very high temperatures (ASTM, v. 15.01 indicates high temperature at >1,000oF). The high- temperature materials are generally non-metallic and are commonly composed of, but not limited to, oxides of aluminum, calcium, magnesium, and silicon. Refractory materials are common in linings for furnaces, kilns, and incinerators, and are used in some crucibles. Fire clays are often used to manufacture refractory materials.
See fire clay