Introduction to High-Temperature Kiln Refractory Bricks

There are many types of industrial kilns, generally speaking, they are mainly divided into four types: hot blast furnaces, aluminum melting furnaces, cement kilns, glass kilns, ceramic kilns, coke ovens, fluidized bed incinerators, etc. During the construction process they all need refractory bricks, so what are the high-temperature kiln refractory bricks they use? Let me give you a brief introduction:

1. Refractory materials for glass tank kiln

According to the working environment of the glass tank kiln, factors such as chemical erosion, mechanical erosion, temperature fluctuations, and high-temperature effects that cause kiln lining damage should be comprehensively considered. The selection of kiln materials mainly includes the following series:

1.1 Al₂O₃-SiO₂ series: mainly includes clay bricks and silica bricks.

1.2 Al₂O₃-ZrO₂-SiO₂ series: mainly includes zircon bricks and fused zirconium corundum bricks.

1.3 ZrO₂-SiO₂ series;

1.4 MgO-Al₂O₃, MgO-Cr₂O₃, MgO-SiO₂ series;

1.5 Insulation materials

2. Cement kiln refractory materials

The refractory materials used in cement kilns are a variety of materials and should be used in combination. There are mainly the following categories:

2.1 Alkaline refractory materials; the main varieties of alkaline refractory materials are: magnesia chrome bricks, magnesia bricks, spinel bricks, dolomite bricks, etc. Magnesia chromium bricks are divided into ordinary magnesia chromium bricks, direct magnesia chromium bricks, and semi-direct magnesia chromium bricks.

2.2 Aluminum-silicon refractory materials; In addition to ordinary clay bricks and high-aluminum bricks, the aluminum-silicon refractory materials used in cement kilns also have their special requirements. Mainly changes in wear resistance, alkali resistance, and temperature resistance. Therefore, a series of special high alumina bricks have been developed, such as phosphate high alumina bricks, phosphate high alumina wear-resistant bricks, spalling-resistant high alumina bricks, and alkali-resistant semi-acidic clay bricks.

2.3 Insulation refractory materials; mainly include silicate cover plates and lightweight insulation bricks.

2.4 Pouring materials. Cement kiln pouring materials include high-strength and high-alkali pouring materials, anti-crushing pouring materials, low-cement refractory pouring materials, special pouring materials for kiln mouths, special pouring materials for coal injection pipes, special pouring materials for tertiary air ducts, and wear-resistant pouring materials.

3. Castables for ceramic kilns

The wall materials in the kiln are required to be high-temperature resistant, and the type of refractory material selected depends on the baking temperature of the product.

3.1 Clay refractory bricks are used at temperatures below 1300℃;

3.2 High alumina bricks are used at 1300~1400℃;

3.3 Use silica bricks at 1400~1500℃;

3.4 Magnesia-alumina bricks are used at 1500~1600℃;

3.5 Below 1800℃, use corundum bricks.

4. Coke ovens are made of refractory materials

4.1 Refractory materials for the carbonization chamber; Clay bricks were mostly used in the past, but now high-quality high-alumina bricks, silica bricks, and andalusite bricks tend to be used.

4.2 Refractory materials used in the combustion chamber. The combustion chamber and the carbonization chamber share the furnace wall, and the bricks are the same as the carbonization chamber.

4.3 The furnace top is made of refractory materials. Due to large temperature fluctuations, clay bricks are used around the coal loading hole on the furnace top, and silica bricks are used in other parts.

4.4 The chute shall be made of refractory materials. The chute connects the combustion chamber and the regenerator, requiring the brick structure to be stable and able to resist thermal stress. Small coke ovens use clay refractory bricks, and large and medium-sized coke ovens use silica bricks.

4.5 The regenerator uses refractory materials. The single vertical walls, partition walls, bottom and checker brick masonry of small coke oven regenerators are all made of clay bricks, while the regenerators and upper masonry of large and medium-sized coke ovens are all made of silica bricks to make the coke oven uniform as a whole.

4.6 The small flue is made of refractory materials. The small flue is located at the bottom of the regenerator and is connected to the flue. All small flues are made of clay bricks.

5. Refractory materials for fluidized bed incinerators

The combustion temperature of the fluidized bed incinerator is 750 to 870℃. Since the materials in the furnace (carrier and waste residue) boil and flow turbulently, the lining material requires heat-resistant and wear-resistant refractory materials. This furnace is constructed of heat-resistant and wear-resistant concrete, with a total thickness of 250mm. The inner layer uses 150mm lightweight heat-resistant concrete as the insulation layer; the outer layer (working layer) is poured with 100mm thick aluminum phosphate alumina concrete [alunite clinker: low calcium aluminate cement: aluminum hydroxide fine powder: aluminum phosphate solution 100:25:25:20～24 (Wt)], or use lightweight insulation bricks and first-grade high alumina bricks (L2-65).