The difference between high-alumina bricks and magnesia-carbide bricks

High-alumina bricks and magnesia-carbon bricks are both types of refractory bricks, but they differ significantly. One belongs to the alumina-silica refractory category, while the other falls under the magnesia-based refractory category. They exhibit substantial variations in raw material composition, applications, and other aspects. Today, we will explore the distinctions between high-alumina bricks and magnesia-carbon bricks by examining their raw material composition, uses, and performance characteristics.

1.Differences in Raw Material Composition Between High-Alumina Bricks and Magnesia-Carbon Bricks

1. High-alumina bricks are primarily composed of high-alumina bauxite clinker, typically containing over 48% alumina (Al₂O₃).

2. Magnesium-carbon bricks are usually made from raw materials including fused magnesia or sintered magnesia, flake graphite, organic binders, and antioxidants. Their main components are magnesium oxide (MgO) and carbon (C).

2.Differences in Physical and Chemical Properties Between High-Alumina Bricks and Magnesia-Carbon Bricks

1. Refractoriness: The refractoriness of high-alumina bricks generally ranges from 1750-1790°C, while magnesia-carbon bricks typically achieve refractoriness exceeding 2000°C.

2. Bulk Density: The bulk density of high-alumina refractory bricks ranges from 2.3 to 2.6 g/cm³, while magnesia-carbon bricks typically reach 3.12 g/cm³.

3. Compressive Strength: The room-temperature compressive strength of high-alumina refractory bricks is usually around 50-80 MPa, whereas magnesia-carbon bricks generally exceed 40 MPa.

4. Apparent Porosity: The apparent porosity of high-alumina refractory bricks is generally ≤20%, while magnesium-carbon bricks are typically required to be ≤10%.

5. Linear Change Rate: The linear change rate of high-alumina bricks is generally 0.4%, whereas magnesium-carbon bricks are typically 0.05%.

3.Differences in Performance Between High-Alumina Bricks and Magnesia-Carbon Bricks

1. High-Alumina Bricks: Possess high refractoriness, load-bearing softening temperature, and mechanical strength, with good slag resistance. However, their thermal shock resistance is relatively weak.

2. Magnesia-Carbide Bricks: Exhibit excellent resistance to slag erosion, thermal shock resistance, and thermal conductivity. However, under high-temperature oxidizing atmospheres, graphite readily oxidizes, thereby compromising their performance.

4.Differences in the Applications of High-Alumina Bricks and Magnesia-Carbide Bricks

1. High-Alumina Bricks: High-alumina bricks are widely used in the lining construction of high-temperature industrial furnaces across industries such as steel, cement, and glass, including blast furnaces, hot blast stoves, and aluminum melting furnaces.

2. Magnesia-Carbon Bricks: Magnesia-carbon bricks are primarily employed in converters, electric furnaces, and ladles within steel mills, typically to resist erosion from molten steel and slag.

The above outlines the differences between high-alumina bricks and magnesia-carbon bricks. Each has distinct advantages and disadvantages. When selecting, one must consider not only the physical and chemical properties of the material itself but also the characteristics of the operating medium and the working environment. Furthermore, price is also a factor to consider. Generally, magnesia-carbon bricks are more expensive than high-alumina bricks. Therefore, a comprehensive evaluation is necessary during selection.

Magnesia Carbon Bricks