Burners are key components in industrial furnaces, responsible for the combustion of fuel. The working environment is usually high temperature and has drastic temperature changes. Therefore, the burner lining material needs to have excellent high temperature resistance, thermal shock resistance, spalling resistance and chemical erosion resistance. Anti Flaking Castables for Burners are refractory materials specially designed for such extreme conditions.
1. Composition and formula optimization of anti-stripping castables for burners
Aggregate system:
High alumina/corundum (Al₂O₃≥80%): Provide basic refractoriness (≥1700℃) and high temperature strength.
Silicon carbide (SiC): Enhance thermal conductivity (3~5 W/m·K) and thermal shock resistance, and reduce temperature gradient stress.
Chromium oxide (Cr₂O₃): Add 3%~8% to improve the ability to resist erosion by alkaline gases (such as K₂O, Na₂O).
Matrix optimization:
Ultrafine powder technology: Use α-Al₂O₃ powder (≤5μm) and silica fume (SiO₂≥90%) to fill pores and reduce apparent porosity (<15%).
Binding system: Low cement (CaO≤4%) or phosphate bonding to reduce the formation of low eutectic phase at high temperature and increase the load softening temperature (≥1550℃).
Reinforcement phase:
Heat-resistant steel fiber (1%~3%): 304/310 stainless steel fiber, length 10~20mm, improves flexural strength (≥8MPa) and anti-stripping.
Zircon (ZrSiO₄) particles: introduce some monoclinic zirconium oxide (m-ZrO₂) to inhibit crack propagation by phase transformation toughening effect.
2. Application location and working condition adaptation of anti-stripping castables for burners
Burner head: directly in contact with flame (temperature 1300~1600℃), using high Cr₂O₃ content formula (such as Cr₂O₃ 8%+SiC 15%) to resist erosion by reducing atmosphere.
Nose area: eroded by high-speed airflow (＞30m/s), adding SiC aggregate (particle size 3~5mm) to improve surface hardness (Mohs hardness ≥8).
Swirl area: needs to be resistant to temperature difference shock (frequent start and stop), and through the composite of steel fiber (310 material) and zircon, dual protection against thermal shock and wear resistance is achieved.