Within the cement sector, the transitional area of the rotary kiln is a pivotal region where temperatures can escalate to around 1400°C. This particular zone endures more intense heat in comparison to other segments like the preheating and cooling areas. The firing section, safeguarded by the kiln's protective layer, maintains a relatively lower brick surface temperature. Silica bricks, which commence softening under load at temperatures above 1500°C, are particularly adept at withstanding such conditions. These bricks are characterized by a dense structure made up of high-hardness minerals such as corundum, silicon carbide, and mullite. Their compressive strength and load softening temperature significantly surpass those of anti-stripping high-alumina bricks. Although their thermal shock stability, corrosion resistance, wear resistance, and thermal conductivity are not exceptionally high, these attributes are well-suited to the requirements of the rear transitional area. The lifespan of silica refractory bricks is 1.5 to 2 times longer than that of anti-peeling bricks. They exhibit commendable wear resistance, making them ideal for cooling belts with a service life exceeding two years, which is 3 to 5 times longer than that of high alumina bricks. Nowadays, different grades of silica firebricks with varying properties are applied according to the specific conditions of different sections of the rotary kiln.
Performance Advantages
1. High Load Softening and Excellent High-Temperature Resistance: The actual detection value of the load softening temperature is stably above 1680°C, a significant improvement over silica bricks and comparable to magnesia-aluminum spinel bricks.
2. High Strength and Wear Resistance: The actual test value of strength is stably above 160MPa, more than three times the strength of silica firie bricks. The increased strength makes them less prone to damage during handling and construction, thereby enhancing wear resistance. They are particularly suitable for use 2 to 3 meters from the kiln mouth.
3. Low Thermal Conductivity and Good Thermal Insulation: The thermal conductivity of magnesia-aluminum spinel bricks is relatively high, leading to elevated kiln shell temperatures. In contrast, silica bricks, being part of the high-alumina-silicon carbide series, have lower thermal conductivity. This characteristic allows for a reduction in kiln shell temperature by more than 50°C during the same period.
4. Excellent Thermal Shock Resistance: Their good thermal shock stability makes them well-suited to the frequent temperature fluctuations in the front transition zone.
5. Moderate Density and Reduced Kiln Load: The bulk density of silica bricks is more than 8% lower than that of magnesia-aluminum spinel bricks, resulting in a more than 8% reduction in kiln load within the same unit length of the kiln.
