Chrome corundum bricks add chromic oxide to a corundum body, and that addition changes how the brick behaves at temperature. Chromia raises refractoriness, suppresses wetting by slag and alkali, and improves thermal shock resistance - the three mechanisms that attack regenerators, port...
Chrome corundum bricks add chromic oxide to a corundum body, and that addition changes how the brick behaves at temperature. Chromia raises refractoriness, suppresses wetting by slag and alkali, and improves thermal shock resistance — the three mechanisms that attack regenerators, port structures and burner zones. XZK's range covers Cr2O3 from 10% to 30% in four grades.
XZK-CC10, XZK-CC12, XZK-CC15 and XZK-CC30 are produced at our Xinmi plant in Henan. The lower-chrome grades serve regenerator condensation-zone courses and port structures; the 30% grade is reserved for the most heavily attacked positions.
Chrome corundum is a corundum-chromia solid solution. Chromic oxide and aluminium oxide form a continuous solid solution, so the chromia is not a separate phase sitting at the grain boundaries but part of the crystal lattice itself. That is why a moderate chromia addition changes the surface chemistry of the brick: molten slag and alkali no longer spread across the hot face, and the corrosion reaction at the face, which depends on continuous wetting, is slowed rather than merely resisted by bulk.
The four grades trade alumina for chromia. CC10 carries at least 10% Cr2O3 and 83% Al2O3; CC15 carries at least 14.5% Cr2O3 and 78% Al2O3; CC30 carries at least 30% Cr2O3 and 62% Al2O3, with bulk density raised to 3.40 g/cm3. Every grade reaches a cold crushing strength of at least 100 MPa and a refractoriness under load of at least 1700°C, with iron oxide held to 0.3% and apparent porosity to 17% or below.
Thermal shock is the property that decides life in a reversing furnace, and it is measured in air cooling from 950°C. The CC10, CC12 and CC15 grades reach at least 12 cycles. That rating is what allows them to survive port service, where the brick face alternates between flame and cold secondary air every 20 to 30 minutes for years. Chromia also reduces the thermal expansion mismatch between the phases in the body, so cracks are less likely to start at the hot face in the first place. The CC30 grade uses a different balance: maximum chrome for corrosion, at a lower thermal shock rating, for positions where chemical attack rather than cycling governs.
| Technical Properties | XZK-CC10 | XZK-CC12 | XZK-CC15 | XZK-CC30 |
| Al₂O₃ (%) | ≥ 83.0 | ≥ 80.0 | ≥ 78.0 | ≥ 62.0 |
| Cr₂O₃ (%) | ≥ 10.0 | ≥ 12.0 | ≥ 14.5 | ≥ 30.0 |
| Fe₂O₃ (%) | ≤ 0.3 | ≤ 0.3 | ≤ 0.3 | ≤ 0.3 |
| Bulk Density (g/cm³) | ≥ 3.25 | ≥ 3.25 | ≥ 3.25 | ≥ 3.40 |
| Apparent Porosity (%) | ≤ 17 | ≤ 17 | ≤ 17 | ≤ 17 |
| Cold Crushing Strength (MPa) | ≥ 100 | ≥ 100 | ≥ 100 | ≥ 100 |
| Refractoriness Under Load (0.2MPa, ℃) | ≥ 1700 | ≥ 1700 | ≥ 1700 | ≥ 1700 |
| Thermal Shock Resistance (950℃ air-cooled, cycles) | ≥ 12 | ≥ 12 | ≥ 12 | - |
Test methods follow GB/T and ISO practice; ASTM equivalents and full certificates of analysis are issued with every shipment.
Selection within the range follows one rule: raise chromia as the chemical attack rises, and accept the accompanying reduction in thermal shock rating only where the position is not being cycled hard.
Chrome corundum bricks serve the regenerator and the combustion system, where alkali vapour, sulphate condensate and repeated reversal cycling do the damage.
Manufacturing is controlled from raw material through to finished brick. Four automatic batching lines feed 20 CNC presses ranging from 630 to 2000 tonnes, so density is set by press force rather than operator judgement, and firing runs through four 108-metre fully automatic tunnel kilns and five ultra-high-temperature shuttle kilns for a uniform soak.
Every batch is tested for bulk density, apparent porosity, cold crushing strength and refractoriness under load, and ships with a certificate of analysis. XZK Group holds ISO 9001, ISO 14001, ISO 45001 and ISO 50001 certification and operates the Henan Provincial Engineering Technology Research Center for Sintered Refractories for Glass Furnaces.
Chrome corundum bricks are used through the regenerator and combustion system together with cylindrical chrome corundum bricks for checkerwork, Three-Resistant bricks where thermal shock is also severe, magnesia bricks for the top hot zone, sillimanite bricks for rider arches and low porosity fire clay bricks for the outer wall. See the regenerator refractory range or browse all refractory products.
Al₂O₃:≥62%;
Cr₂O₃:≥10%;
Cold Crushing Strength:≥100MPa;
Al₂O₃:≥80%;
Bulk Density:≥2.75g/cm³;
Cold Crushing Strength:≥85MPa;
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