Mullite Insulation Bricks are made of high-quality and high-purity refractory materials.
According to the specific gravity of the product, organic composite
fillers are added, vacuum extrusion molding, and high temperature
sintering to synthesize light mullite products.With its light weight and excellent thermal insulation properties,
lightweight mullite bricks are widely used in the hot surface
refractory lining or insulation layer of a variety of thermal
equipment, creating conditions for improving the energy efficiency
of the equipment. High-alumina refractories with mullite as the main crystal phase
generally have an alumina content between 50% and 75%.
The refractory temperature of mullite lightweight brick can reach above 1790℃. The starting
temperature of load softening is 1600-1700℃. Pressure resistance at
room temperature is slightly 70-260MPa. Good thermal shock
resistance. There are two types of sintered mullite bricks and fused mullite bricks. Sintered mullite
bricks are made of high-alumina bauxite clinker as the main raw material, adding a small amount of clay or raw bauxite as a binding
agent, and forming and firing.
Fused mullite bricks use high alumina bauxite, industrial alumina and refractory clay as raw
materials, add charcoal or coke fine particles as reducing agents, and are manufactured by reduction fusion method after molding. The
crystallization of fused mullite is larger than that of sintered mullite, and its thermal shock resistance is better than
that of sintered products. Their high temperature performance mainly depends on the content of alumina and the uniformity of
mullite phase and glass distribution. A high-alumina refractory with mullite (3Al2O3·2SiO2) as the main
crystal phase.
Generally, the alumina content is between 65% and 75%. In addition to mullite, the mineral composition with lower
alumina also contains a small amount of glass phase and cristobalite; the higher alumina contains a small amount of
corundum. Lightweight mullite bricks can be directly used for the lining of high-temperature kilns, and have been widely used in
shuttle kilns, roller kilns, glass and petrochemical kilns.
Features of Lightweight Mullite Bricks:
1. Low thermal conductivity, with good thermal insulation effect;
2. Low thermal melting, due to low thermal conductivity, mullite series light insulation
bricks accumulate very little heat energy, which has obvious energy saving effect in intermittent operation;
3. Low impurity content has very low iron box alkali metal and
other oxide content, therefore, high refractoriness; high aluminum
content makes it maintain good performance in a reducing
atmosphere;
4. High compressive strength in hot state;
5. Accurate appearance and size, speed up the masonry, reduce the
amount of refractory clay used, ensure the strength and stability
of the masonry, thereby extending the life of the lining;
6. It can be processed into special shapes to reduce the number of
bricks and joints. Lightweight mullite bricks can be used as
refractory lining or thermal insulation layer of hot surface
working layer.
