Product Description of Rongsheng Refractory Supply Long-term Use
Below 1700℃ Alumina Refractory Brick For Industrial Kiln
Alumina refractory bricks are insulating refractory products made
primarily from fused corundum, sintered alumina, and industrial
alumina. They are characterized by strong resistance to acidic and
alkaline atmospheres, excellent reduction resistance, and good
thermal shock resistance. These bricks can be used continuously at
temperatures below 1700°C.
The production process for alumina refractory bricks employs two
methods: the foam method and the burnout additive method.
Foam Method: This involves preparing a foam slurry using rosin soap
foaming agents, finely ground raw materials, binders, and other
additives. The slurry is cast into molds, dried, fired, shaped, and
inspected to produce the final product. Bricks made by this method
have uniform structure, low thermal conductivity, and excellent
insulation performance.
Burnout Additive Method: This method uses polystyrene spheres as
burnout additives to manufacture alumina insulating refractory
bricks.
Production Process for Alumina Refractory Bricks
1.Raw Materials and Additives
The primary raw materials are fused corundum, sintered alumina, and
industrial alumina, with polystyrene spheres serving as burnout
additives. Silica or other materials are used as volume
stabilizers, providing bonding at both room and high temperatures.
Binders are also added.
2.Mixing, Molding, and Forming
The proportions of materials are determined based on the required
bulk density and physical-chemical properties of the product.
Mixing is performed using a mixing machine or slurry agitator. The
sequence is as follows: polystyrene spheres → part of the binder
and water → powder materials → binder. Forming is achieved by
vibration molding or other suitable methods, or by slurry casting
into molds.
3.Drying and Firing
During drying, polystyrene spheres expand significantly at
90–110°C, then liquefy, vaporize, and oxidize. Most manufacturers
pre-expand the spheres before production to mitigate excessive
volume changes during drying. The drying temperature should not be
too high or rapid, and the residual moisture in the dried brick
should be less than 2%. Kilns are side-loaded for firing. At
low-temperature stages, attention must be paid to the volume
changes of burnout materials. The firing temperature is determined
based on the brick’s bulk density and physical-chemical properties
and typically exceeds 1600°C. The firing process for these bricks
can be faster than that for dense bricks.
Features and Applications
Alumina insulating refractory bricks are lightweight, have high
compressive strength, low thermal conductivity, minimal shrinkage
during firing, and excellent thermal shock resistance. They are
suitable for use as insulation layers in high-temperature
industrial furnaces, as well as working linings for kilns directly
exposed to flames and precision thermal equipment. However, they
are not ideal for areas in direct contact with molten metal or
slag. They exhibit high stability in reducing atmospheres, and
their usage temperature, depending on the purity of the product,
generally ranges from 1650°C to 1800°C.
With strict quality management and a highly skilled technical team,
Zhengzhou Rongsheng Refractory is committed to providing
environmentally friendly, reliable, and energy-efficient alumina
refractory bricks to society.
