Refractory Brick Classification & Selection Guide

Refractory bricks are classified by chemical-mineral composition: fireclay, high-alumina, silica, magnesia and more. This article reviews their properties and applications with a selection method.

选型2026-09-10

Refractory Brick Classification and Selection Guide

1. Basic Classification

Refractory bricks are classified by chemical-mineral composition into six families: fireclay brick (Al₂O₃ 30–48%, weakly acid to neutral, economical with good thermal-shock resistance, for medium-low temperature zones); high-alumina brick (Al₂O₃≥48%, grades LZ-55/65/75, temperature and slag resistance rising with content); silica brick (SiO₂≥94%, acid-slag resistant with high RUL, the recommended choice for coke ovens); magnesia and magnesia-based bricks (MgO≥90%, basic, extremely resistant to basic slag, for non-ferrous smelting and ladles); special bricks (corundum, mullite, SiC) for severe hot zones; and lightweight insulating bricks for insulation layers. Shapes range from standard to special and super-special.

2. Properties of Each Family

Fireclay: refractoriness ~1710℃, good thermal-shock resistance and low cost, but limited hot load capacity—for upper stacks and flues. High-alumina: refractoriness rises from 1770℃ to above 1790℃ with Al₂O₃, strength and slag resistance improving in parallel—the largest shaped-brick volume in steel, cement and non-ferrous. Silica: RUL above 1620℃ with stable long-term volume, but poor thermal-shock resistance requiring careful heating—mainly coke ovens and glass furnace crowns. Magnesia: refractoriness above 2000℃, extremely resistant to basic and iron-oxide slag, but poor thermal-shock resistance and hydration sensitivity—protect from moisture in storage. SiC: high conductivity, wear resistance and thermal-shock resistance—preferred for waste incineration and hot abrasion duty.

3. Core Selection Parameters

Check five parameters: service temperature and fluctuation—sets the grade; contact media—acid/basic/neutral slag and atmosphere set the material family; load conditions—load-bearing zones need high RUL; abrasion and scouring intensity—sets wear grade; maintenance cycle and budget—affects grade and economics. Judge all five together, not temperature alone.

4. Common Selection Mistakes

Mistake 1: selecting by temperature only, ignoring media—acid bricks in basic slag fail fast. Mistake 2: one brick for the whole furnace—zones differ, zoned selection is more rational. Mistake 3: ignoring thermal shock—furnaces cycling frequently must prioritize shock-resistant bricks. Mistake 4: ignoring brick shape and joint design—complex zones without special shapes or overly wide joints shorten life. Mistake 5: looking at unit price only—per-tonne consumption cost is the real cost.

5. Recommended Selection Process

Five steps: ① list zonal operating parameters (temperature, media, load, wear); ② preliminarily choose the material family; ③ verify key indicators (refractoriness, RUL, thermal shock, wear); ④ determine shape and size (standard/special, joint design); ⑤ finalize grade against maintenance cycle and budget. When in doubt, submit operating parameters for a technical selection proposal.

6. Conclusion

Brick selection is essentially matching duty, material and cost. Understand the property boundaries of the six families, avoid common mistakes and select systematically to significantly improve lining life and value. Henan Songrui New Refractory Materials Co., Ltd. supplies fireclay, high-alumina, silica, magnesia, corundum, mullite, SiC bricks and the full special-shape range with duty-based customization.

Slide Gate Plates: Alumina-Carbon vs Alumina-Zirconia-Carbon, Bore Sizing and Sliding Face Control

Locate the failure mode first, then pick the grade. Properties and application limits for alumina-carbon versus alumina-zirconia-carbon with 8–15% ZrO2; bore sizing from 25 to 55 mm against ladle capacity and casting speed; 4–6 versus 8–12 heats per campaign; where the 0.03 mm flatness and 0.05 mm parallelism limits come from; why preheat and no-preheat routes must not be mixed; and the three incoming checks.

Checker Bricks for a Glass Furnace Regenerator: Three Brick Types by Temperature Zone, Plus the Thickness Calculation

With more than 600 °C across the checkerwork, brick selection has to be zonal: magnesia (MgO ≥90%) at 1350–1550 °C, LZ-65 or mullite in the middle, low-porosity fireclay (≤15%) at 700–1100 °C. Includes the 40/30 mm thickness versus 38–58 m²/m³ surface-area calculation, joint and expansion-gap values, and four measurable rejection signals.

Blast Furnace Lining Refractory Selection Guide: Full-Process Zone Material Selection for 10+ Year Long-Life Furnace | Henan Songrui New Refractory Co., Ltd.

Henan Songrui New Refractory Co., Ltd. details the full-process blast furnace lining refractory selection solution: from micro-porous corundum bricks at the hearth to alkali-resistant high-alumina bricks at the throat, precise zone-specific material selection for 10+ year long-life furnaces. Annual capacity 800,000 tons, full furnace refractory customization supported, 7-day fast delivery.