Refractory brick is a ceramic material that is normally used in high-temperature environments because of its lack of flammability, and because it is a decent insulator, which reduces the amount of energy loss.
At elevated temperatures, substances with liquid phases usually react chemically with the refractory brick, resulting in refractory consumption. Although it may not be immediately obvious, the oxidation and reduction state of the environment as redox conditions or oxygen activity can participate in and influence the chemical reactions that are to take place.
A fire brick is a block of refractory ceramic material used in lining furnaces, kilns, fireboxes, and fireplaces. A refractory brick is designed mainly to withstand high heat, but should also usually have a low thermal conductivity to save energy. Usually dense bricks are used in applications with extreme mechanical, chemical, or thermal stresses, such as the inside of a wood-fired kiln or a furnace, which is subject to abrasion from wood, fluxing from ash or slag, and high temperatures.
These bricks are favorable at corrosion resistance and chemical resistance. They include a huge amount of magnesia and here also lime is utilized as a binding material. Various basic fire bricks usable are Magnesite bricks, Magnesia-carbon, magnesia-chrome bricks, etc.