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Refractory materials are classified into three types based on fusion temperature (melting point). Normal refractories have a fusion temperature of 1580–1780 °C (e.g. fire clay) High refractories have a fusion temperature of 1780–2000 °C (e.g. chromite) Super refractories have a fusion temperature of > 2000 °C (e.g. zirconia)
Cement plant clinker dust is more abrasive than sand. In high temperature ducts, or ducts with wear potential, 2 + 1 ⁄ 2-inch refractory, is often anchored to the duct plate with V anchors at 6" O.C. (+/-) to resist a) temperature, or b) wear at elbows or a combination of these effects. Occasionally ceramic tiles or ceramic mortars are ...
The purpose of the refractory lining is to insulate the steel shell from the high temperatures inside the kiln, and to protect it from the corrosive properties of the process material. It may consist of refractory bricks or cast refractory concrete, or may be absent in zones of the kiln that are below approximately 250 °C (482 °F).
High-temperature applications, such as masonry ovens and the like, generally require the use of a refractory cement; concretes based on Portland cement can be damaged or destroyed by elevated temperatures, but refractory concretes are better able to withstand such conditions.
The strength and high-temperature stability of refractory metals make them suitable for hot metalworking applications and for vacuum furnace technology. Many special applications exploit these properties: for example, tungsten lamp filaments operate at temperatures up to 3073 K, and molybdenum furnace windings withstand 2273 K.
In the making of firebrick, fire clay is fired in the kiln until it is partly vitrified.For special purposes, the brick may also be glazed. There are two standard sizes of fire brick: 9 in × 4 + 1 ⁄ 2 in × 3 in (229 mm × 114 mm × 76 mm) and 9 in × 4 + 1 ⁄ 2 in × 2 + 1 ⁄ 2 in (229 mm × 114 mm × 64 mm). [2]
After building of a new refractory-lined industrial furnace or equipment, or refractory maintenance or relining of existing equipment, a necessary step is the start-up of the operation, which usually involves heating-up the unit in a controllable way, in order to prevent spalling or shortening of the materials' predicted lifetime.
In Middle and South Europe, grog is used to create fire-resistant chamotte type bricks and mortar for construction of fireplaces, old-style and industrial furnaces, and as component of high temperature application sealants and adhesives. A typical example of domestic use is a pizza stone made from chamotte. Because the stone can absorb heat ...