A refractory is a material that retains its shape and chemical identity when subjected to high temperatures and is used in applications that require extreme resistance to heat.
There are four basic forms in which refractories are manufactured:
- shaped products (bricks),
- unshaped products (monolithics),
- functional products and
- heat insulating products.
The bricks are used to form the wall, arches, and floors of various high-temperature equipment while the unformed compositions which include mortars, gunning mixes, castable (refractory concretes), and ramming mixes are cured in place to form. Functional products are used mainly as tap and gas purging systems in steel manufacturing while heat-insulating are products for the refractory lining of thermal plants.