Blast Furnace Refractory Bricks – Grades, Performance & Procurement Guide
May 22, 2026Complete guide to blast furnace lining: GL series high alumina, microporous carbon, ceramic cup. Anti-alkali, long campaign life. Chinese & ASTM grades.
1. Application Overview
Blast furnace (BF) is the core ironmaking equipment. Its lining is divided into five functional zones based on temperature, mechanical load, and chemical attack.
2. Zonal Working Conditions
|
Zone |
Temperature |
Main Damage Mechanism |
|
Upper shaft |
400–800°C |
Impact, thermal shock, CO attack |
|
Lower shaft/belly |
800–1300°C |
Alkali (K, Na) penetration, Zn erosion |
|
Bosh/belly |
1100–1600°C |
Slag skin removal, creep, CO decomposition |
|
Tuyere zone |
1500–2000°C |
Thermal stress, iron/slag wash, oxidation |
|
Hearth/bottom |
1450–1550°C |
Molten iron penetration, cyclic flow |
3. Recommended Materials & Grades
|
Zone |
Chinese Grade |
International Equivalent |
Key Properties |
|
Upper shaft |
GL-48, GL-55 high alumina |
ASTM Type I/II, ISO 10081 |
Thermal shock ≥25 cycles (1100°C water quench) |
|
Lower shaft |
GL-65, zirconia-containing high alumina |
ASTM Type III, DIN 1089 |
Alkali resistance: strength retention ≥75% |
|
Bosh/belly |
Corundum-mullite, SiC composite |
Si₃N₄-SiC (ISO 15378) |
RUL T₂ ≥1650°C, porosity ≤14% |
|
Tuyere zone |
Si₃N₄-bonded SiC brick |
SiC-Si₃N₄ |
Thermal conductivity ≥16 W/(m·K) at 1000°C |
|
Hearth/bottom |
Microporous carbon + ceramic cup |
Microporous carbon + alumina castable |
Apparent porosity ≤16%, micropore ratio ≥85% |
4. Procurement KPIs (Mandatory Tests)
Alkali attack test (GB/T 14982 / ASTM C454): strength retention ≥75%
Refractoriness under load (RUL) T₂ ≥1600°C (lower shaft and below)
Thermal shock resistance ≥25 cycles (1100°C → water)
Gas permeability of carbon brick ≤0.05 µm²
SiC brick: free Si ≤0.5%, Fe₂O₃ ≤0.8%
5. Service Life & Cost Model
|
Zone |
Standard life (years) |
Optimised life (years) |
Cost increase |
ROI |
|
Upper shaft |
5–7 |
8–10 |
+20% |
Recommended |
|
Lower shaft |
3–5 |
6–8 |
+40% |
Must upgrade |
|
Tuyere |
2–3 |
5–6 |
+80% |
Critical investment |
|
Hearth |
10–12 |
15–18 |
+60% |
Standard choice |
6. Common Failure Modes & Prevention
Alkali cracking in lower shaft → use zirconia-containing or andalusite bricks.
Tuyere premature wear → increase SiC content, use composite blocks.
Elephant foot hearth erosion → high-conductivity microporous carbon + ceramic cup + optimised cooling.
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