Calcined kaolin is widely used in refractories, mainly in the following aspects:

I. Refractory bricks

Calcined kaolin is an important raw material for manufacturing refractory bricks, which has high fire resistance and can bear the load in high temperature environment without deformation. Refractory bricks are widely used in lining of high temperature furnaces in steel, cement, ceramics and other industries. For example, high-alumina calcined kaolin can be used to make high-alumina refractory bricks, and its fire resistance can reach above 1750 C.

II. Refractory castable

Calcined kaolin can be used to produce refractory castable, which has good fluidity and construction performance and is suitable for repairing and building the lining of high temperature furnaces. Its chemical stability is high, and it can resist the corrosion of acidity, alkalinity and slag slurry.

III. Refractory fibers

Calcined kaolin can be used to prepare aluminum silicate fiber, which has extremely high whiteness and good thermal insulation performance and can be used as thermal insulation material in high temperature environment. For example, coal-series kaolin clinker can be used to prepare high-purity aluminum silicate fiber with smooth surface and low slag ball rate.

IV. Mullite products

Calcined kaolin is a natural raw material for synthesizing mullite, which has high hardness and high refractoriness, and is widely used to manufacture mullite lightweight bricks, mullite fibers and other refractories. For example, calcined kaolin with 45% Al₂O₃ content can be used to synthesize mullite, and its mullite content can reach 69.5%.

V. Refractory cement

Calcined kaolin can be used to make refractory cement, which has good high temperature resistance and can be used for building and repairing high temperature furnaces.

VI. Precision casting

Calcined kaolin can be used as precision casting sand or casting powder, and its fine particles and high purity can ensure the surface quality and dimensional accuracy of castings. For example, calcined kaolin can be used to make models of precision castings such as turbine blades.

VII. Thermal insulation materials

Calcined kaolin can be used to produce light heat insulation refractory materials, such as aluminum silicate fiber felt, insulating brick, etc. These materials have good thermal insulation performance and can effectively reduce the heat loss of high-temperature equipment.

VIII. Other applications

Calcined kaolin can also be used to make refractory coatings, refractory fiberboards and other products, which are widely used in construction, metallurgy, chemical industry and other industries.

To sum up, calcined kaolin has a wide application prospect in the field of refractories because of its excellent fire resistance, chemical stability and physical properties.