The simplest and most direct answer to the question of what refractory means is fire-resistant materials. Refractory materials are materials that can withstand high temperatures for a long time and therefore have many industrial uses. The simplest example of this is firebricks. refractories; It is generally used in the construction of furnaces, reactors, industrial steam boilers and furnaces. A refractory material must be resistant to thermal shocks. However, the answer to the question of what is refractory, of course, does not consist only of fire bricks. In general, any non-metallic material that can be used at temperatures above 538 C (1,000 F) without deteriorating its chemical and physical structure falls within the scope of this definition. In this regard, one of the most important distinguishing features of refractory materials emerges: they are not metallic materials.