Description of Corundum Brick
Corundum brick is a refractory product with 90% Al2O3 content, and its main crystalline phase is corundum. The working temperature of corundum bricks reaches 1800℃.Corundum refractories are also known as alumina refractories. To make corundum refractory, electroless corundum powder and technical alumina are used. After forming, the product is fired at 1600-1750°C.
Characteristics of Chinese grade Corundum Bricks
| Subject/Sort | GYZ-99A | GYZ-99B | GYZ-98 | GYZ-95 | |
|---|---|---|---|---|---|
| ω (Al2O3)/% | ≥ | 99.0 | 99.0 | 98.0 | 95.0 |
| ω (SiO2)/% | ≤ | 0.15 | 0.2 | 0.5 | / |
| ω (Fe2O3)/% | ≤ | 0.10 | 0.15 | 0.2 | 0.3 |
| Apparent porosity,/% | ≤ | 19 | 19 | 19 | 20 |
| Bulk density (g/cm³) | ≤ | 3.20 | 3.15 | 3.15 | 3.1 |
| Cold crushing strength/MPa | ≥ | 80 | 80 | 80 | 100 |
| Constant linear change (1600℃*3h)/% | Xmin Xmax | -0.2~+0.2 | -0.2~+0.2 | -0.2~+0.2 | -0.3~+0.3 |
| 0.2 MPa 0.6% Underload on refractoriness/℃ | Xmin | 1700 | 1700 | 1700 | 1700 |
Characteristics of Russian grade Corundum Bricks
| Name of indicator | KC-95 | KC-90 |
|---|---|---|
| Al²O³, over | 95 | 90 |
| Fe²O³, not more | 0,6 | 0,8 |
| Open porosity, %, not more than | 24 (28) | 24 (28) |
| Compressive strength, N/mm2, not less than | 40 (20) | 50 (20) |
| Softening onset temperature, °С, not lower | 1680 | 1660 |
Classification of Corundum Bricks
Depending on the composition of the chemical it can be divided into:
Mullite corundum bricks are a special type of refractory brick that is made from a mixture of mullite and corundum.Mullite corundum refractory bricks contain a high percentage of aluminum oxide over 72 to 90 (Al2O3) in their composition.
- Al2O3: 72-90%
- Open porosity: 16%-24%
- Softening onset temperature: 1500°C-1660°C
- Cold crushing strength: 45-70MPa
| Name of indicators | ISS-72 | MCP - 72 | MKS-90 |
|---|---|---|---|
| Mass fraction, %: | |||
| Al2O3 , not less | 72 | 72 | 90 |
| Fe2O3, not more | 1,5 | 1,5 | 0,8 |
| Additional linear shrinkage, at temperature 1600 °C, not more than | 1,0* | 1,0 | - |
| Open porosity, %, not more than | 24 | 16(18) | 24 |
| Compressive strength, N/mm², not less than | 30 | 80(30) | 50 |
| Softening onset temperature, °С, not lower | 1 500 | 1550 | 1 660 |
Chrome Corundum bricks are corundum refractories containing Cr2O3. At high temperature, Cr2O3 and Al2O3 form a continuous solid solution, so the high temperature performance of chrome corundum bricks is better than that of pure corundum bricks. It has good resistance to high temperature and slag erosion, and its resistance to slag erosion increases with increasing Cr2O3 content. Chromic corundum bricks are widely used in various industries, including metallurgy, chemical industry, glass industry and other fields where high thermal and chemical resistance is required.
- Al2O3% (≥): 33-80
- Sr2O3: 15-60%
| Physico-chemical parameters | HCT-15 | HKT-30 | HKT-45 | HKT-60 |
|---|---|---|---|---|
| AL2O3, %, not less | 80,0 | 67,0 | 50,0 | 33,0 |
| Sg2O3, %, not less | 15,0 | 27,0 | 45,0 | 60,0 |
| TiO2,% | - | 2 | 2 | 3 |
| Apparent density, g/mm2at least | 3.15 | 3.3 | 3.4 | 3.6 |
| Open porosity, %, not less than | 17 | 17 | 18 | 18 |
| Compressive strength, N/mm2, at least | 75 | 75 | 75 | 75 |
| Heat resistance (1300°C - water) heat-shift, not less than | 5 | 5 | 5 | 5 |
| Deformation onset temperature °С, not lower | 1700 | 1700 | 1700 | 1700 |
| Thermal conductivity, λ, W/m*K, at 1000°C | 2.2 | 2.2 | 2.5 | 2.8 |
| Thermal expansion, % at 1000°C | 0.8 | 0.8 | 0.8 | 0.8 |
Baddeleyite-corundum refractories, known as AZS electro-melting zirconia corundum brick, AZS brick, fused AZS brick.Baddeleyite-corundum refractories belong to the Al2O3 -ZrO2 - SiO2 system. The area of the most common compositions of bacor refractories containing 30 to 42% ZrO2 is determined by the position of ternary eutectic with melting point of 1765℃.
- Al2O3: ≥45-50%
- ZrO2: ≥32.5%-40.5%
- Volumetric Density: 3.75-4g/cm³
- Open porosity: ≤1.0%-1.2%
| Subject/Level | AZS33-Y | AZS36-Y | AZS41-Y | |
|---|---|---|---|---|
| Chemical composition/% | Al2O3 | （Marja） | ||
| ZrO2 | 32.00~36.00 | 35.00~40.00 | 40.00~44.00 | |
| SiO2 ≤ | 16.00 | 14.00 | 13.00 | |
| Na2O ≤ | 1.45 | 1.45 | 1.30 | |
| (Fe2O3+TiO2+CaO+CaO+MgO+Na2O+K2O) ≤ | 2.00 | 2.00 | 2.00 | |
| （Fe2O3+TiO2） ≤ | 0.30 | 0.30 | 0.30 | |
| Bulk density (dense part) (g/cm³) ≥ | 3.75 | 3.80 | 3.95 | |
| Apparent porosity/% ≤ | 1.50 | 1.00 | 1.00 | |
| Erosion rate of antimole glass under static conditions (ordinary soda-lime glass , 1500 ℃ × 36h)/(mm/24h) ≤ | 1.60 | 1.50 | 1.30 | |
| Initial liquid phase precipitation temperature ℃ ≥ ≥ | 1400 | 1400 | 1400 | |
| Bubble release rate % (1300°C X 10 hours, plain soda-lime glass) ≤ | 2.00 | 1.50 | 1.00 | |
| Exudation of vitreous phase (1500 ℃×4 hours)/% ≤ | 2.00 | 3.00 | 3.00 | |
| Thermal expansion rate (room temperature ~1000 ℃)/% ≤ | Provide measured data | |||
| Bulk density /(kg/m3) | TP、QX ＞ | 3400 | 3450 | 3550 |
| ZWS ＞ | 3600 | 3700 | 3850 | |
| WS ＞ | 3700 | 3750 | 3900 | |
According to the raw materials and processing methods, it can be categorized into：：
Sintered corundum brick is a product made of sintered corundum and fine corundum powder as raw materials, which are mixed, molded, dried and fired. Its firing temperature is 1650-1800 ℃, sometimes reaching 1850 ℃. The corresponding increase of firing temperature can improve the strength and density of the product.
Electro-fused corundum brick is made of crushed particles of fused corundum clinker and fine powder, a small amount of clay and binder is added, and after complete mixing, it is molded under high pressure and fired at a temperature of 1700-1800 ℃.
Fused corundum brick is the melting of industrial alumina, a small amount of soda ash and silica powder in an electric arc furnace, and then after many processes such as casting, annealing, inspection, cold working and pre-assembly, it is given the desired shape and size.
Преимущества Корундового кирпича
The softening point under load of corundum brick is usually between 1600-1800 degrees Celsius, and its refractory temperature can reach 1770-2000 degrees Celsius.
Corundum brick has a very high hardness, the hardness of corundum brick is close to hardness 9 on the Mohs scale, which is second only to diamond, harder than steel.
Corundum bricks have high corrosion resistance to various acids, alkalis and chemical solutions and can work stably in aggressive chemical environments.
Corundum bricks are highly resistant to wear and tear. They can withstand abrasion and long-term operation under high temperature conditions.
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Application of Corundum Bricks
Corundum bricks are used in high-temperature processes in the metallurgical industry, including the production of steel, iron, aluminum and other metals. Corundum bricks are used in furnaces, burners, ladles, crystallizers and other installations where high temperature resistance and fire resistance are required.
In the glass industry, corundum bricks are commonly used as lining material for glass furnaces. Corundum bricks can withstand high temperature and chemical erosion in the glass production process to protect the furnace structure, and can effectively ensure glass quality and production efficiency.
Corundum bricks have high wear resistance. In the refining industry, corundum bricks are used to create refractory furnaces, reformers, crackers and other installations where high resistance to high temperatures and chemicals is required.
Corundum brick has excellent corrosion and abrasion resistance, which can provide a stable and reliable working environment for chemical reaction equipment, so corundum brick is often used to create the inner lining of high temperature chemical reaction equipment.
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