Many people may wonder, why are silicon carbide bricks much more expensive when they are both called refractory bricks? The answer lies in the raw materials, processes and performance advantages.
1.High starting point of raw materials
The core raw material of silicon carbide bricks is silicon carbide, which itself has a relatively high cost.
Silicon carbide rarely exists in nature and needs to be synthesized artificially. This process involves reacting raw materials such as quartz sand in a high-temperature electric arc furnace. The temperature must reach over 2000°C. This process consumes enormous amounts of energy.
high alumina bricks
In addition, high-quality silicon carbide bricks have strict requirements on the purity of raw materials. Usually the SiC content may be ≥90% or even higher. At the same time, impurities need to be removed during the purification process, and the process involved is very complicated. All of these have further pushed up the cost of raw materials.
In contrast, the raw materials for ordinary clay bricks or high-alumina bricks are abundant and easy to purify. In this way, the price difference is very obvious.
2.Production process barriers
The production process of silicon carbide bricks is complex and has high technical barriers.
(1)Molding process
High-pressure forming equipment is required here, and the pressure must reach more than 100MPa to ensure that the bricks have uniform density and low porosity. This places extremely high demands on equipment performance and mold precision.
silicon carbide bricks
(2)Firing process
The firing process is more critical. Silicon carbide bricks are fired in a reducing atmosphere at high temperatures, typically between 1400-1600°C. The firing cycle is as long as 7-10 days. Ordinary refractory bricks, on the other hand, are fired at lower temperatures, with a firing cycle of only 3-5 days.
(3)Additional processes
In addition to the necessary processes, some silicon carbide bricks also require some additional processes to improve performance. For example, adding antioxidants (such as metallic silicon, silicon powder) or performing surface coating treatment. These additional processes also increase production difficulty and cost.
3.Performance advantages of silicon carbide bricks
The excellent performance of silicon carbide bricks is the core support for their high price. Silicon carbide has high hardness, high thermal conductivity, and excellent thermal shock resistance. These properties enhance its irreplaceability.
For example, in the transition zone of a large cement rotary kiln, the service life of silicon carbide bricks can reach 2-3 years. The lifespan of ordinary high alumina bricks is only 8-12 months.In the furnace body of iron-making blast furnace, its resistance to alkali metal corrosion is far better than clay bricks or corundum bricks.
clay brick
In short, although the unit price is high, it has a long life and requires less replacement frequency. These features make its overall cost of use lower.
At the same time, this “high investment, high return” characteristic also determines its market positioning.
Therefore, when choosing silicon carbide bricks, it is important to select a refractory brick supplier with high adaptability and scientifically select materials to truly achieve efficient and stable operation under high temperature conditions.
