Refractories have multiple useful applications. In the metallurgy industry, refractories are used for lining furnaces, kilns, reactors, and other vessels which hold and transport hot mediums such as metal and slag.

Firing involves heating the refractory material to high temperatures in a periodic (batch) or continuous tunnel kiln to form the ceramic bond that gives the product its refractory properties. The final processing stage involves milling, grinding, and sandblasting of the finished product.

The typical refractory materials include fireclay refractories, high alumina refractories, silica brick, Magnesite refractories, Chromite refractories, Zirconia refractories, Insulating materials and Monolithic refractory.

Minerals commonly used for refractories include (but are not limited to) alumina, bauxite, graphite, kaolin, magnesia and zirconium. These minerals are produced globally but, in some cases, not always of grades suitable for refractory applications (e.g., alumina and bauxite).

The Indian refractory industry is a Rs 9,000 crore market, with major players such as TRL Krosaki, Dalmia OCL, RHI Magnesita India. About 75% of the refractories manufactured using magnesia, alumina or silica is used with the rest being consumed by cement and glass, ceramics, petrochemicals and boiler industries.

Insulating refractories include calcium silicate materials, kaolin, and zirconia. Insulating refractories are used to reduce the rate of heat loss through furnace walls.

11.5 Refractory Manufacturing 11.5.1 Process Description1-2. Refractories are materials that provide linings for high-temperature furnaces and other processing units. Refractories must be able to withstand physical wear, high temperatures (above 538°C [1000°F]), and corrosion by chemical agents.

Shapeless refractories are normally dispatched from the refractory manufacturing plant not as a refractory but as refractory materials which become refractory only after it undergoes mixing, forming, aging, drying, and preheating etc. at the site of use.

The refractory bricks are formed by various methods which include either hand moulding or in different types of forming and moulding machines which includes presses. The type of moulding adopted depends on the shapes and sizes of the refractory and its quantity.

The extent of drying time, which varies with refractory mixes, generally is between 24 to 48 hours. Although heat may be generated specifically for dryer chambers, it usually is supplied from the exhaust heat of kilns to maximize thermal efficiency.