Should clay fire bricks or concrete be used for furnace walls and bottom? Direct comparison of which is better requires specific analysis based on specific working conditions.
1.Temperature resistance difference: clay fire bricks are better than concrete
The most fundamental difference between the two is high temperature resistance.
low-porosity-clay-bricks
Concrete is mainly made of a mixture of cement, sand, gravel and water. It contains a large amount of chemically bound water and free water, and has a low thermal surface limit. When the temperature exceeds 400℃, it will begin to dehydrate, the strength will be halved at 600℃, and it will become powder at 800℃.
Clay refractory bricks, by contrast, are a completely different story. It is calcined at high temperature, and its main mineral components are mullite and cristobalite.
Therefore, it has excellent refractoriness and can usually withstand high temperatures above 1300°C.
In addition, clay fire bricks can not only maintain structural stability at high temperatures, but also withstand certain mechanical loads. This is why it has become one of the preferred materials for high-temperature furnace linings.
2.Unique advantages of clay refractory bricks: strong chemical stability
Concrete is strongly alkaline overall because it contains calcium hydroxide, a product of cement hydration.
clay brick
In industrial kilns, concrete linings can be rapidly eroded if exposed to acidic slag or gases, significantly shortening their service life.
In contrast, the main chemical components of clay bricks are silicon dioxide (SiO₂) and aluminum oxide (Al₂O₃), which are acidic or neutral refractory materials.
Therefore, it has good resistance to corrosion by acidic substances and is particularly suitable for furnaces that handle acidic materials. For example, certain parts of glass melting furnaces, steel blast furnace bodies, etc.
Of course, if the furnace environment is strongly alkaline, you need to choose alkaline refractory bricks, such as magnesia bricks, magnesia-chrome bricks, etc.
3.Clear division of physical performance and application scenarios
Concrete has high compressive strength at room temperature and is an ideal building structural material. Therefore, it is widely used in house, bridge and road construction. However, its thermal shock resistance is extremely poor and it cannot withstand the frequent heating and cooling processes of the furnace.
Magnesia brick
Although the compressive strength of clay refractory bricks at room temperature may not be as good as that of high-strength concrete, their key performance lies in their mechanical performance and thermal shock stability at high temperatures. It can maintain a certain integrity during repeated temperature changes, ensuring the long-term stable operation of the furnace. For example, in equipment such as hot blast furnaces, heating furnaces or cement rotary kilns, the performance of clay bricks cannot be replaced by concrete.
In short, there is no absolute answer to the question of whether clay bricks are better than concrete. The choice of bricks should be based on the actual working conditions. Of course, for high-temperature industrial environments, clay bricks are undoubtedly the best choice.
