Here's the problem with refractory brick selection: there are dozens of product names, and every supplier has slightly different grade designations. A buyer searching for "1600°C refractory brick" finds fire clay bricks (wrong), high alumina bricks (maybe), corundum bricks (overkill), and everything in between.
This page is a single-source map. Every major brick type, their temperature ceiling, chemical composition range, and where they work. Use it to narrow the field to 2–3 candidates, then request specific TDS data for your application.
Quick Reference - All Brick Types by Temperature Band
| Brick Type | Al₂O₃ (%) | Max Service Temp (°C) | Bulk Density (g/cm³) | Typical CCS (MPa) | Primary Application |
|---|---|---|---|---|---|
| Fire clay brick | 30–45 | 1350–1400 | 1.90–2.20 | 25–50 | General industrial, chimney |
| SK-34 / SK-36 fire clay | 35–42 | 1380–1450 | 2.00–2.25 | 30–60 | Blast furnace backup, boiler |
| Alumina-silica (T-28) | 45–55 | 1450–1500 | 2.20–2.45 | 50–80 | Kiln general lining |
| High alumina (T-33) | 65–72 | 1550–1600 | 2.40–2.60 | 65–100 | Rotary kiln, cement preheater |
| High alumina (T-38) | 75–82 | 1600–1650 | 2.55–2.70 | 80–120 | Cracking furnace, ladle backup |
| High alumina (T-42) | 85–92 | 1650–1700 | 2.65–2.80 | 100–150 | EAF upper shell, glass upper structure |
| Mullite brick | 65–75 | 1650–1700 | 2.50–2.70 | 80–130 | Ceramic kiln, hot blast stove |
| Corundum-mullite | 75–85 | 1700–1750 | 2.75–2.95 | 90–150 | Glass regenerator, ceramic kiln roof |
| Sintered corundum | 92–96 | 1750–1800 | 3.00–3.30 | 110–170 | EAF upper zone, glass crown |
| Fused corundum | 98–99 | 1800+ | 3.40–3.55 | 150–220 | Glass tank, direct melt contact |
| MgO-C brick | 65–80% MgO | 1750 (basic slag) | 2.85–3.05 | 30–50 | BOF, EAF slag zone, ladle |
| Silicon carbide brick | 70–90% SiC | 1600–1700 | 2.55–2.80 | 80–140 | Blast furnace, incinerator, Al furnace |
Values represent typical production ranges. Specific grades vary by manufacturer.
1350°C–1450°C Range: Fire Clay and Alumina-Silica Bricks
Fire clay brick and SK-series alumina-silica bricks cover most general industrial applications: boilers, chimney linings, municipal waste incinerators (lower zones), and blast furnace backup positions.
Fire clay brick: Al₂O₃ 30–45%. The standard workhorse below 1400°C. Available in dozens of standard shapes (straight, arch, wedge, key) with tight dimensional tolerances. Cost-effective for large-volume applications, frequently paired with calcium silicate board backup insulation. Not suitable for direct slag contact or reducing atmospheres with sulfur.
SK-34 / SK-36: The "SK" designation is a Japanese Industrial Standards classification (roughly equivalent to ISO 1109 PC series). SK-34 = refractoriness 1760°C with a 2% creep-under-load temperature of approximately 1350°C. SK-36 is slightly better. These are widely specified in Asia for general industrial applications.
Where fire clay fails fast: Contact with basic slag (basicity index >1.5), direct alkali vapor exposure, and temperatures above 1450°C. If your furnace shows fire clay brick degrading in 3–6 months, check slag chemistry or actual temperature profile - one of these is almost always the cause.
1500°C–1600°C Range: High Alumina Options
The 1500–1600°C range is where most cement kiln, rotary kiln, and heat-treatment furnace applications sit. High alumina brick with 65–82% Al₂O₃ covers this range.
T-33 grade (65–72% Al₂O₃): The entry point for high alumina. RUL T₀.₅ ≈ 1450°C. Adequate for cement preheater zones and heat-treatment furnace walls. Price: approximately 2× fire clay brick.
T-38 grade (75–82% Al₂O₃): Step up for rotary kiln main zones, cracking furnace linings, and petrochemical application. RUL T₀.₅ ≈ 1500°C. Bulk density 2.55–2.70 g/cm³. The most commonly specified grade in industrial furnace construction (for monolithic unshaped installations in this range, consider high alumina castable refractory).
Selection boundary: Fire clay vs. high alumina: The practical decision point between fire clay and high alumina brick lies at 1450°C and chemical exposure. Below 1450°C in clean atmospheres without slag, standard fire clay provides adequate service. Once service temperatures exceed 1450°C, or when alkali vapor, basic slag, or strict refractoriness-under-load (RUL >1400°C) are present, transitioning to T-33 or T-38 high alumina is essential to prevent rapid thermal creep.
Application check before ordering T-38:
Is your kiln atmosphere reducing? If yes, T-38 is fine.
Is there alkali vapor (K₂O, Na₂O) above 1000°C? If yes, consider moving to T-42 or mullite.
Is there direct contact with basic slag? If yes, high alumina is wrong - go to MgO-C or spinel.
1600°C–1700°C Range: Premium High Alumina and Corundum
At this temperature range, two product families compete: premium high alumina (T-42, 85–92% Al₂O₃) and entry-level corundum (corundum-mullite, 75–85% Al₂O₃).
T-42 high alumina (85–92% Al₂O₃): RUL T₀.₅ ≈ 1580–1630°C. Widely specified for electric arc furnace refractory upper shells, glass furnace upper structures, and ceramic kilns where temperatures occasionally spike above 1600°C. Cost: approximately 3–4× fire clay brick.
Mullite brick (65–75% Al₂O₃, mullite phase): Mullite's unique thermal shock resistance makes it the preferred choice for applications with daily thermal cycling above 1500°C - shuttle kilns, batch furnaces, hot blast stove dome. The mullite crystal network absorbs thermal stress that would crack pure alumina brick. (For lightweight energy-saving backup linings, see our mullite insulating brick line).
Corundum-mullite (75–85% Al₂O₃): The transition material between high alumina and pure corundum. Combines the RUL advantage of high Al₂O₃ content with the thermal shock resistance of the mullite phase. Best of both worlds for glass furnace regenerator zones and ceramic kiln structural positions.
1700°C–1800°C+: Corundum, Silicon Carbide, and Fused Cast
Above 1700°C, only four material families are practical: sintered corundum, fused corundum, SiC-based brick, and fused cast AZS (alumina-zirconia-silica). This is the territory of glass furnaces and specialty high-temperature kilns. For full property tables across corundum grades, consult our guide on corundum brick types and specs.
Sintered corundum (92–96% Al₂O₃): The standard choice for EAF upper zone above 1650°C and glass furnace crown. Bulk density 3.0–3.3 g/cm³. Cost: approximately 4–5× fire clay brick.
Fused corundum (98–99% Al₂O₃): Maximum temperature resistance, maximum chemical purity. For direct glass contact and laboratory furnaces above 1750°C. Cost: 8–12× fire clay brick. Don't specify fused corundum when sintered corundum will serve - the cost premium is substantial.
Silicon carbide (SiC) brick: A different trade-off - high thermal conductivity (8–18 W/m·K vs. 2–3 for alumina brick), superior abrasion resistance, but moderate maximum temperature (1600–1700°C for oxide-bonded grades). Correct choice for blast furnace tuyere zone, incinerator grate, and aluminum melting - NOT for glass furnace crown. (For unshaped lining maintenance, see silicon carbide castable).
Fused cast AZS: The glass industry standard for below-glass-line contact in high-production float glass furnaces. Al₂O₃ 45–50%, ZrO₂ 30–45%, SiO₂ ~15%. Extremely high resistance to glass melt corrosion. Expensive and long lead time - this is project-specific material.
Upper temperature limits summary: For ultra-high-temperature installations requiring continuous operation above 1800°C, fused corundum (99% Al₂O₃) stands as the highest-rated standard oxide brick in reducing or neutral atmospheres. When aggressive direct molten glass contact occurs up to 1700°C, fused cast AZS provides the best chemical erosion barrier. Beyond 1800°C in specialized metallurgy, customized zirconia or stabilized magnesia compositions become necessary.
How Furnace Atmosphere Changes Your Selection
Temperature rating is only part of the selection equation. Atmosphere determines whether your brick survives to its rated temperature:
Oxidizing atmosphere (excess air, combustion furnaces):
High alumina and corundum brick: fully compatible at rated temperature
SiC brick: compatible up to 1400°C (forms passive SiO₂ layer; above 1400°C in strong oxidizing conditions, this can cause volume instability)
MgO-C brick: NOT compatible (carbon oxidizes rapidly above 700°C)
Reducing atmosphere (CO-rich, hydrogen, reformer environments):
High alumina and corundum: compatible, but avoid high-SiO₂ grades - SiO₂ reduces to volatile SiO above 1400°C in strong reducing conditions
SiC brick: compatible, especially nitride-bonded grades
Mullite brick: compatible for moderate reducing conditions
Alkali vapor attack (K₂O, Na₂O in cement kilns, glass furnaces):
Fire clay and standard high alumina: react with alkali, forming eutectic melt that reduces effective RUL
Mullite brick: resistant due to stable mullite phase
MgO-spinel: resistant (used in cement kiln burning zone specifically for alkali resistance; learn more about the basic family in our magnesia refractory materials guide)
Cost vs. Performance - Lifecycle Value Analysis
Lowest initial purchase cost rarely equates to lowest total operating cost. The metric that matters in furnace operations is cost per month of active campaign life. When upgrading furnace efficiency, replacing heavy brick backups with modern ceramic fiber blanket furnace lining frequently delivers the fastest payback.
Case evaluation: Rotary kiln refractory economics:
| Material Grade | Initial Investment Index | Typical Campaign Life | Normalized Annual Cost Index |
|---|---|---|---|
| High alumina T-33 | Baseline (1.0x) | 12 months | 1.00 |
| High alumina T-38 | ~1.4x | 20 months | 0.84 |
| Mullite-spinel brick | ~2.0x | 36 months | 0.67 |
In high-wear rotary kilns, upgrading to mullite-spinel increases initial lining expense by approximately 2×, but extends lining life threefold. The result is a 33% reduction in normalized annual refractory cost - before accounting for the substantial savings in lost production hours and labor during unplanned relining shutdowns.
Multi-zone lining strategy in industrial kilns: Optimizing refractory cost requires zoning rather than single-material blanket purchasing. In a modern cement rotary kiln:
Burning zone (1450°C clinker temp): Basic magnesia-spinel or magnesia-zirconia bricks resist alkaline clinker melt.
Upper & lower transition zones: High alumina T-38 (75–82% Al₂O₃) provides thermal fatigue resistance.
Preheater & calciner ducting: High alumina T-33 or alkali-resistant castables offer wear protection without excessive material mass.
Cooling zone: Abrasion-resistant high alumina or SiC castables withstand rapid clinker impact.
The caveat: this lifecycle optimization holds only when the material matches the specific operational atmosphere. Installing an over-specified 95% corundum brick in a 1350°C position increases expenditure without delivering any performance differentiation over standard fire clay or T-33 bricks.
Technical Consultation & Quote Request
We stock fire clay through sintered corundum - all standard shapes, key bricks, and arch series.
Provide your furnace type, operational temperature profile, gas atmosphere, and estimated brick count. Our refractory engineering team will configure the appropriate grade map and provide a formal commercial proposal within 4 business hours.
Email: inquiry@topower.tech
Batch-specific test certificates (CCS, RUL, apparent porosity) and TDS files available upon inquiry.
