Insulating Firebrick JM-23 — Lightweight Mullite-Silica IFB, Max 1260°C
JM-23 lightweight mullite-silica insulating firebrick rated to 1260°C continuous service. Low thermal mass for fast heat-up cycles. ThermalEast sources from Pingdingshan for pottery kilns, ceramic tunnel kilns, and heat treatment furnace buyers worldwide.
Buyer Brief
JM-23 is the entry-level lightweight insulating firebrick for continuous service up to 1260°C, with a mullite-silica mineralogy at 0.75–0.85 g/cm³ — roughly one-third the density of dense fireclay brick. The reduced thermal mass measurably shortens heat-up and cool-down times in periodic kiln service. Standard supply is 230 × 114 × 65 mm straight brick with tapered arch and wedge shapes available on FCL orders. Non-combustible, asbestos-free, ASTM C155 / GB/T 3994 compliant. For service above 1260°C or reducing atmospheres, uprate to JM-26 or JM-28.
Spec Snapshot
| Property | Unit | Value |
|---|---|---|
| Maximum service temperature | °C | 1260 |
| Al₂O₃ (%) | % | 45–55 |
| Bulk density | g/cm³ | 0.75–0.85 |
| Thermal conductivity at 500°C | W/(m·K) | 0.20–0.25 |
| Cold crushing strength | MPa | ≥2.0 |
| Permanent linear change at 1230°C | % | ≤±1.0 |
| Standard size | mm | 230 × 114 × 65 |
| Standard reference | — | ASTM C155 / GB/T 3994 |
| Atmosphere compatibility | — | Oxidising (air); see notes for reducing |
| Asbestos content | — | None |
Use Cases
Pottery and ceramic tunnel kilns. Sidewall and crown lining replacement — reduces thermal mass per linear metre by ~60% vs dense brick, cutting gas consumption ~14% per firing cycle.
Heat treatment furnace backup insulation. Rigid brick format maintains full contact with the hot-face castable through thermal cycling, unlike mineral wool which settles and creates cold spots over time.
Glass lehr insulation. Lightweight crown and sidewall lining minimises thermal gradients from uneven heat storage. Pairs with diatomite insulating brick for cold-face backup.
Why ThermalEast
ThermalEast sources JM-23 from qualified Pingdingshan-region manufacturers at direct mill pricing, with batch CoA documentation and consolidated shipping alongside other IFB grades.