Fire Clay
Fire clay refers to a range of refractory clays used in the manufacture of ceramics, fixtures and furnaces. Fire clay is remarkably heat-resistance and is used in a variety of industries including foundries, ceramics, casting moulds and the manufacturing of refractory products for high-temperature applications.
Fire Clay Definition
Fire clay is composed of hydrated silicon dioxide and aluminium oxide, and often contains other oxides, such as calcium and magnesium, which add to its properties. It usually has a plastic consistency, making it easy to mould and shape when mixed with a sufficient amount of water. When it is heated to a high temperature (greater than 1,450°C), fire clay transitions from a plastic form to its permanent shape.
Fire Clay Uses
Fire clay is used in a wide range of applications and industries. As a refractory material, fire clay is capable of withstanding extreme temperatures and is applied to the inside surfaces of fixtures, foundries and furnaces which are required to operate at high temperatures. Fire clay has good insulating properties and is also used in non-refractory applications, including pottery kilns, water heaters and gas fireplaces.
Fire clay is also used in the production of refractory ceramic material. Fire clay is mixed with fluxes such as alumina and silica to produce a wide range of shapes and sizes, which are then used in a variety of high-temperature applications.
Fire Clay Composition
Fire clay has a fusion point of around 1,450°C and has a density of around 2.3 g/cm3. In its most common form, fire clay is composed of approximately 40% aluminium oxide, 40% silica, 3% iron oxide and various other trace elements, including calcium oxide and magnesium oxide. Fire clay is also a hydrated material, meaning it contains water molecules on its molecular structure, which increases its heat resistance.
Fire Clay Properties
Fire clay has many properties which make it an ideal material for high-temperature applications. Fire clay is very resistant to thermal shock, meaning it can withstand rapid changes in temperature without cracking or crumbling. Fire clay also has excellent insulating properties and is capable of withstanding temperatures of up to 1,700°C. However, fire clay is susceptible to mechanical wear and should be used in low-stress, low-impact applications in order to maximise its lifetime.
Conclusion
Fire clay is a highly heat-resistant material used in a wide range of applications. It is composed of hydrated silicon dioxide and aluminium oxide, and has excellent thermal, electrical and mechanical properties. Fire clay is used in the manufacture of ceramics, fixtures and furnaces and is ideal for high-temperature applications due to its energy efficiency and heat resistance.
