Corundum refractory balls are spherical heat-exchange media for regenerator packing, where the bed must absorb and release heat cycle after cycle without spalling, sagging or blocking the gas path. Made from the same corundum raw materials as our dense corundum bricks, they bring high...
Corundum refractory balls are spherical heat-exchange media for regenerator packing, where the bed must absorb and release heat cycle after cycle without spalling, sagging or blocking the gas path. Made from the same corundum raw materials as our dense corundum bricks, they bring high refractoriness and abrasion resistance to a shape designed for gas flow.
XZK Group supplies corundum refractory balls from our Xinmi plant in Henan as a complete regenerator packing or as a replacement charge for existing checkerwork, sized to the void fraction and pressure drop of the chamber they fill.
A corundum refractory ball is a high-alumina sphere formed by pressing or rolling corundum aggregate and alumina powder and then sintering the shape to develop the corundum bond. The body is dense, hard and chemically inert, with corundum as the dominant crystalline phase and no exudable glassy phase. Because it is a sphere, the packing has no flat faces and no mortar joints, so it contains none of the joint planes that open under thermal cycling in a stacked checker wall.
Balls are produced to a controlled diameter band, screened for size and roundness, and fired in tunnel or shuttle kilns. Dimensional consistency matters as much as chemistry here: an out-of-tolerance batch changes the void fraction of the bed and with it the pressure drop and the heat-transfer behaviour of the whole regenerator, so size control is treated as a quality parameter and not a packaging detail.
Random packing of spheres creates a large, evenly distributed heat-exchange surface with a high void fraction. Gas flows around the balls instead of channelling through straight vertical flues, which lowers pressure drop and removes the dead zones where sulphate condensate collects and sets. Because each sphere can settle individually, the bed absorbs thermal expansion without accumulating the compressive load that cracks stacked checker brick. A corundum ball also resists the abrasive batch dust carry-over that rounds off and eventually crushes softer fireclay packings.
| Performance Indicators / Products | 90 Series | 92 Series | 95 Series | 99 Series |
| Al₂O₃% | ≥ 90 | ≥ 92 | ≥ 95 | ≥ 99 |
| Fe₂O₃% | ≤ 0.3 | ≤ 0.25 | ≤ 0.15 | ≤ 0.1 |
| Water Absorption % | ≤ 0.8 | ≤ 0.8 | ≤ 0.8 | ≤ 0.8 |
| Bulk Density (g/cm³) | ≥ 2.8 | ≥ 3.0 | ≥ 3.1 | ≥ 3.2 |
| Packing Density (g/cm³) | ≥ 1.7 | ≥ 1.9 | ≥ 2.0 | ≤ 2.1 |
Ball sizes are selected against the regenerator's target void fraction, gas velocity and allowable pressure drop, since diameter controls both the heat-exchange surface and the resistance to flow. A smaller ball raises surface area and heat recovery but also raises pressure drop; a larger ball keeps the bed open but stores less heat per unit volume.
Diameter band and the batch certificate of analysis — alumina content, bulk density and refractoriness under load — are issued with every order, so the packing can be matched to the duty of a specific chamber rather than supplied as a generic grade.
Corundum balls are used where the regenerator design calls for a pellet bed rather than stacked checkerwork, and where the packing must stay open under dust and condensate loading.
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.
Corundum balls work inside the same regenerator system as cylindrical chrome corundum bricks and flat chrome corundum bricks for the condensation zone, sillimanite bricks and andalusite bricks for rider arches and load-bearing courses, and magnesia bricks for the top hot zone. See the regenerator refractory range for zoning guidance or browse all refractory products.
Acid Resistance, %:＞99.8;
Bulk Density, g/cm3:2.3-2.4;
Water Absorption, %:≤0.5;
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