Silicon carbide brick refers to refractory bricks with silicon carbide as the main raw material and silicon carbide as the main crystalline phase. Silicon Carbide Refractory Bricks have good acid resistance, alkali resistance, wear resistance, high strength, high thermal shock resistance, low coefficient of thermal expansion, and good thermal conductivity. However, they have the disadvantage of poor oxidation resistance at high temperatures and relatively higher prices.
In the metallurgical industry, silicon carbide bricks are suitable for special parts of furnaces and kilns. They are commonly used in non-ferrous metallurgy, such as the trays of tower zinc distillation furnaces, the bodies of vertical retort zinc distillation furnaces, and the secondary air nozzles of blast furnaces. In the steel industry, they are often used as linings for ladles, taphole plugs, blast furnace hearths, furnace bodies, iron troughs, converter and electric furnace tapholes, as well as waterless cooling runners in heating furnaces. The manufacturing process of silicon carbide bricks typically involves mixing SiC grains, SiC powder, and binders, followed by molding, drying, and firing.
Silicon carbide fire bricks can be classified based on the different binders between silicon carbide particles:
Oxide (or silicate) bonded silicon carbide, such as SiO or clay-bonded silicon carbide.
Silicon nitride (Si₃N₄) bonded silicon carbide.
Silicon oxynitride (Si₂O₃N₂) bonded silicon carbide.
Sialon bonded silicon carbide.
Self-bonded (also known as pure SiC bonded) silicon carbide.
To discern the quality of silicon carbide bricks, several factors can be considered. Firstly, the dimensions and specifications of the bricks should meet the requirements. The density of silicon carbide bricks is generally between 2.45 and 2.6, and deviations from this range may indicate impurities or the addition of other refractory materials, affecting the silicon carbide content and thermal conductivity. When purchasing silicon carbide bricks, it is important to inspect the surface for any missing corners or cracks. While minor defects within the national standard range are acceptable, serious deviations beyond the standard indicate poor quality.
Silicon carbide refractory materials have diverse applications due to their special properties. They are widely used in the manufacturing of muffle furnaces, heating furnace bottoms and heat exchangers, crucibles, carburizing boxes, thermocouple protection tubes, one-end closed temperature measuring tubes, and large bricks. Silicon carbide bricks are also used in various indirectly heated kiln structures, such as zinc distillation towers, vertical and horizontal distillation tanks. The high thermal conductivity of silicon carbide allows it to be used in the production of wear-resistant components, including low-temperature rails and tie rods, as well as heavily worn parts such as cyclones, dust collectors, pipelines, troughs, furnace bottoms, grid plates for tunnel kiln cars, and porous products for filtration. The excellent chemical properties of silicon carbide refractory bricks make them effective in various kilns and devices in non-ferrous metallurgy and chemical industries. They are also used in steam boilers. However, the use of silicon carbide refractory materials in industry is still not extensive enough. In recent years, there has been an increase in the production scale of these bricks, providing possibilities for their widespread use in industries such as ceramics, non-ferrous, and ferrous metallurgy.
If there are issues such as cracking, spalling, or excessive wear of refractory materials, it is important to identify the root causes and analyze the true reasons. Rongsheng Refractory Materials has been engaged in the production and development of refractory materials for many years, and we are capable of solving various challenging problems related to high-temperature furnace linings. We welcome inquiries and technical exchanges from new and old friends alike.