How Fire Bricks Are Made

How Fire Bricks Are Made

Fire bricks, also known as refractory brick, are ceramic building materials in blocks that are used in construction to withstand high temperatures. They are a key component of kilns, furnaces, fireplaces and specialized structures like wood burning stoves and pizza ovens. They have a lower thermal conductivity than regular bricks, which increases energy efficiency. They are also dense which helps them resist abrasion. Fire bricks are available in different grades, ranging from lightweight insulators to dense, heavy conductors. A manufacturer’s choice of ingredients, additives, pressure and temperature determine the quality of the fire brick.

The basic raw material for fire bricks is fired clay, a fine-grained rock that is formed in the earth over time. This clay has a natural property of alumina and silica that give it refractory qualities – the ability to withstand heat. It was the earliest material to be used in firebricks and has been improved upon by industry over time. Most modern fire bricks are made of alumina, silica and kaolin. Other materials include alumina, magnesia, dolomite, and chromite, which have higher melting points. These additional materials are melted and mixed with the main raw materials to form a mixture that is pressed into shapes or shaped by hand.

Once the raw materials are shaped, they are fired in special kilns. The process of firing and cooling is very controlled to ensure that the bricks can withstand the high temperatures at which they are used. The resulting fire bricks are usually grey in color, although the color of the raw materials can affect the final product.

Hard fire bricks are a type of refractory brick that are used in construction at very high temperatures. They can withstand extreme mechanical and chemical stresses that occur in the structure, as well as high temperatures. The alumina content of the brick is very high, typically between 34-38%. They are generally used in higher temperatures and require a more sturdy design than softer types of fire bricks.

Soft fire bricks are designed for lower temperatures and can withstand abrasion, but they are less dense than hard fire bricks and have poor thermal conductivity. They are often used for lining kilns and fireboxes, or as insulation in wood-burning stoves. They can be made with different alumina contents, from very low-duty to high-duty firebricks, which have a much higher alumina content and are stronger than medium-duty bricks.

Tags:fire clay brick | insulation bricks | refractory bricks