The Reason Why Refractory Bricks Can Withstand High Temperatures

The Reasons Why Refractory Bricks Can Withstand High Temperatures

The ability of refractory bricks to resist high temperatures can be analyzed from the following aspects:

1. High Refractoriness of Raw Materials

The raw materials used to produce refractory bricks are typically natural minerals, such as bauxite, silica, and magnesite. These materials inherently have high refractoriness, forming the foundation for manufacturing refractory bricks.

• Bauxite: Processed bauxite is used to produce aluminosilicate refractory bricks. Its main component, alumina, has a refractoriness of up to 1780°C, along with strong chemical stability and excellent physical properties.
• Silica: The raw material for silica refractory bricks is silica, with SiO₂ as the main component. Higher SiO₂ content correlates with higher refractoriness. Silica bricks are made by combining natural silica with a small amount of mineralizer, then firing at high temperatures to achieve high strength at elevated temperatures.
• Magnesite: Magnesite, the main raw material for producing magnesia refractory bricks, primarily consists of MgO. Magnesium oxide has excellent refractory insulation properties and, after high-temperature calcination, forms crystalline structures with refractoriness exceeding 2000°C.

2. Characteristics of Inorganic Non-Metallic Materials

As inorganic non-metallic materials, refractory bricks derive their functionality from the inherent properties of their raw materials. These materials are typically characterized by high compressive strength, hardness, resistance to high temperatures, and corrosion resistance. These traits ensure that refractory bricks remain stable in high-temperature environments, resisting softening, deformation, or melting.

3. Influence of Manufacturing Processes

The production process plays a significant role in determining the high-temperature resistance of refractory bricks. Key stages include shaping, drying, and firing.

• High-Temperature Sintering: During the firing process, refractory bricks undergo high-temperature sintering to form a dense structure with enhanced mechanical strength. Generally, higher firing temperatures and longer durations improve the high-temperature performance of refractory bricks. However, excessively high temperatures or prolonged firing can alter the crystalline structure, potentially impacting performance.
• Process Control: Precise control of manufacturing processes and parameters is crucial for ensuring the excellent thermal resistance of refractory bricks.

4. High-Temperature Treatment of Finished Products

The finished bricks are subjected to high-temperature treatment in tunnel kilns, reaching temperatures above 1500°C. This process further enhances the thermal resistance of the refractory bricks by densifying their structure, enabling them to better withstand erosion in high-temperature environments.

In conclusion, the ability of refractory bricks to resist high temperatures relies on the high refractoriness of raw materials, the properties of inorganic non-metallic materials, the influence of manufacturing processes, and the high-temperature treatment of finished products. These factors work together to ensure that refractory bricks remain stable and perform well in high-temperature environments.