Refractory Brick and Its Applications

Definition of Refractory Brick

Refractory bricks, as their name suggests, are bricks with high thermal resistance, made from fireclay and kaolin. They are manufactured with a dense and fine molecular structure and are fired at temperatures exceeding 1500 degrees Celsius. Thanks to their exceptional heat resistance, refractory bricks are widely used in kilns, furnaces, ladles, and industrial insulation.In addition to their industrial applications, a more standard variety of refractory bricks is now commonly used for building facades.

Composition of Refractory Bricks

The primary materials in Amiran refractory bricks are special mineral compounds and lightweight volcanic materials that are inherently heat-resistant. These raw materials, known as refractories, are ceramic or non-metallic substances designed to withstand high temperatures. Refractories must retain their desired physical and chemical properties under extreme heat and environmental conditions.

Using Refractory Bricks for Building Facades

Using refractory bricks in building facades ensures that your structure’s exterior will remain as attractive and intact as the day it was built, even for future generations. However, this is only possible if you choose refractory bricks made with a proper, standardized formulation and certified quality.Unfortunately, the market is filled with various facade bricks sold under the name “refractory bricks” that lack the required long-term quality. Over time, these substandard bricks may discolor, deform, develop algae, or suffer from efflorescence. Therefore, when purchasing refractory bricks, it is highly recommended to ask the seller for certifications that guarantee color stability and resistance to efflorescence.

Applications of Refractory Bricks

The most important characteristic of refractory bricks is their high resistance to heat, which makes them an ideal material for lining industrial kilns. They are also suitable for use in fireplaces. Essentially, refractory bricks can be utilized in spaces exposed to high temperatures.It’s important to note that refractory bricks come in various types, depending on the materials used in their composition. Each type is designed to withstand different ranges of heat, based on the specific materials incorporated into their structure.Up until the 1960s, carbon and fireclay were the primary materials used for lining kilns. However, today, the use of refractory bricks for the interior lining of kilns has become widespread and highly advanced.

Types of Refractory Bricks

Refractory bricks come in various types, each capable of withstanding different temperature ranges depending on the materials used in their composition. Up until the 1960s, carbon and fireclay were primarily used for lining kilns. However, with the development of different types of refractory bricks, these bricks are now widely used for the interior lining of kilns.The main types of refractory bricks include:

• Silica Bricks
• Special Refractory Bricks
• Alumina Bricks
• Alkaline Refractory Bricks

Silica Bricks

Bricks made primarily from silica clay are known as silica bricks. Silica clay, also referred to as quartzite, consists mainly of silicon dioxide (SiO2), with smaller amounts of calcium oxide (CaO), titanium oxide (TiO2), and iron oxide (Fe2O3). Pure quartz is often used to create this composition. Silica refractory bricks are commonly used for the inner linings of steel-making kilns. They are also widely utilized in the production of glass, ceramics, and coke ovens due to their high thermal conductivity and excellent impermeability to gases.

Special Refractory Bricks

Special refractory bricks are a unique type made from intermediary metals and are used for specific industrial purposes. The main types of special refractory bricks are:

• Chromium-Corundum Refractory Bricks
  These bricks are composed of 90–95% aluminum oxide (Al2O3) and 5–10% chromium oxide (Cr2O3). They are primarily used in the inner linings of blast furnaces in the steelmaking process.
• Zirconium Refractory Bricks
  These bricks have excellent thermal resistance, making them ideal for use in aluminum smelting furnaces and molten glass kilns.
• Chromium Oxide Refractory Bricks
  These bricks consist of 90–95% chromium oxide (Cr2O3) and are mainly used in the glass manufacturing industry for kiln linings.

Alumina Bricks

The primary material in alumina bricks is aluminum oxide (Al2O3 or alumina), which provides excellent thermal resistance of up to 1750°C. These bricks are also highly resistant to alkalis, making them suitable for the inner linings of metal and iron smelting furnaces, as well as large-scale glass furnaces.

Alkaline Refractory Bricks

Alkaline refractory bricks are composed of magnesium oxide (MgO) and silicon dioxide (SiO2). To enhance their thermal resistance, small amounts of chromium oxide (Cr2O3) and iron oxide (Fe2O3) are often added to the mixture. These bricks are used for the inner linings of open-hearth steelmaking furnaces, rotary cement kilns, the upper sections of glass-melting furnaces, and in the production of non-ferrous metals.

Each type of refractory brick is designed to meet the unique demands of high-temperature industrial processes, ensuring durability and performance under extreme conditions.