What is Mullite Brick?

Mullite bricks are high alumina refractory materials with mullite (3Al2O3 · 2SiO2) as the main crystalline phase. The general alumina content ranges from 65% to 75%. In addition to mullite, the mineral composition also contains a small amount of glass phase and cristobalite, with lower alumina content. Those with higher levels of alumina also contain a small amount of corundum.

Brief description of mullite brick

Mullite, as a good refractory raw material, has high hardness, high melting point, and stable chemical properties. Mullite bricks have a high fire resistance, reaching over 1790 ℃. The starting temperature for load softening is 1600~1700 ℃, with a room temperature compressive strength of 70~260MPa and good thermal shock resistance.

Mullite refractory brick properties

• Good thermal shock resistance
• Low high-temperature creep rate
• Acid resistant slag erosion
• High load softening temperature
• The fire resistance is around 1850 ℃

Physical and chemical index of mullite brick

Item	MK60	MK65	MK70	MK75
Al2O3, %	≥60	≥65	≥70	≥75
SiO2, %	≤35	≤33	≤26	≤24
Fe2O3, %	≤1.0	≤1.0	≤0.6	≤0.4
Apparent Porosity, ％	≤17	≤17	≤17	≤18
Bulk Density, g/cm3	≥2.55	≥2.55	≥2.55	≥2.55
Cold Crushing Strength, Mpa	≥60	≥60	≥80	≥80
0.2Mpa Refractoriness Under Load T0.6 ℃	≥1580	≥1600	≥1600	≥1650
Permanent Linear Change On Reheating,% 1500℃X2h	0～+0.4	0～+0.4	0～+0.4	0～+0.4
Thermal Shock Resistances 100℃ water cycles	≥18	≥18	≥18	≥18
20-1000℃ Thermal Expansich10-6/℃	0.6	0.6	0.6	0.55
Thermal Conductivity (W/MK) 1000℃	1.74	1.84	1.95	1.95

Classification of mullite bricks

There are two types of mullite refractory bricks: sintered mullite bricks and electric fused mullite bricks. Sintered mullite bricks are made from high alumina bauxite clinker as the main raw material, with a small amount of clay or raw alumina added as a binder, and then formed and fired. Electric fused mullite bricks are made from high alumina, industrial alumina, and refractory clay as raw materials, with the addition of charcoal or fine coke particles as reducing agents. After forming, they are manufactured using the reduction electric melting method. 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 the distribution of mullite phase and glass.

Kerui Mullite series refractory bricks

Corundum mullite brick

Corundum mullite bricks refer to high alumina refractory products composed of the main crystalline phases of corundum and mullite. Kerui corundum mullite bricks are made from high-purity or relatively pure raw materials, with a white color and accurate dimensions. They also support customized refractory products. Kerui corundum mullite bricks have excellent corrosion resistance and wear resistance, strong stability, and are not affected by reducing gases such as H2 and CO.

Light weight mullite bricks

Light weight mullite bricks are high alumina refractory materials with mullite as the main crystalline phase. The general alumina content ranges from 65% to 75%. Mullite insulation bricks can be directly used for the lining of high-temperature kilns, and are currently widely used for the lining of shuttle kilns, roller kilns, glass and petrochemical kilns.

Application of mullite refractory brick

• Hot blast furnace top
• Blast furnace body and bottom
• Glass furnace regenerative chamber
• Ceramic sintering kiln, dead corner lining of petroleum cracking system, etc

Mullite brick manufacturer

The purpose of Kerui Material: to serve the global high temperature industry. If you currently have a high temperature equipment construction project, need high quality firebrick masonry, Kerui refractory manufacturers at any time to provide you with free professional refractory consulting services. Kerui is a reliable refractory manufacturer, and we hope to be your best partner in China.