Corundum-mullite honeycomb ceramic heat storage body (circular)

# Corundum-Mullite Honeycomb Ceramic Heat Storage Body (Circular)

In the fields of industrial energy conservation and high-temperature thermal equipment, corundum–mullite honeycomb ceramic heat storage units (cylindrical type) have emerged as a core component for enhancing energy utilization efficiency and reducing pollutant emissions, thanks to their unique structural design and superior material properties. Made primarily from corundum and mullite, this ceramic material achieves highly efficient heat recovery and recycling through a meticulously engineered honeycomb structure, thereby providing critical technological support for the green transformation of industries such as steel, glass, and chemicals.

### Material Properties: The Perfect Combination of High-Temperature Resistance and Thermal Stability

The core advantage of corundum–mullite honeycomb ceramic heat-storage bodies lies in their material composition. The composite structure of corundum (α-Al₂O₃) and mullite (3Al₂O₃·2SiO₂) imparts exceptionally high refractoriness and thermal stability. Experimental data show that the material’s load-softening temperature can reach 1,680°C, with a maximum service temperature exceeding 1,600°C; even under extreme temperature gradients ranging from 1,100°C to 1,600°C, it maintains more than 20 thermal-shock resistance cycles. These properties enable long-term stable operation in high-temperature kilns, effectively preventing cracking or spalling caused by thermal stress.

The material contains 69–72% alumina (Al₂O₃) and 28–30% silica (SiO₂), with a small amount of magnesium oxide (MgO) added as a stabilizer to form a dense crystalline structure. This composition not only enhances the material’s mechanical strength—with a compressive strength exceeding 26 MPa—but also significantly reduces its coefficient of thermal expansion to 4.5–5.2 × 10⁻⁶/°C, thereby minimizing volumetric changes at high temperatures and extending service life.

### Structural Design: Fluid-Dynamic Optimization of Circular Honeycombs

The circular honeycomb ceramic heat storage unit features a millimeter-scale straight-through pore design, with pore diameters typically ranging from 1.99 mm to 4.96 mm and wall thicknesses controlled between 0.5 mm and 1.0 mm. This structure significantly reduces airflow resistance: compared with conventional spherical heat storage units, the pressure drop is reduced by approximately 66%, while the specific surface area is increased to over 1,000 m²/m³, substantially enhancing heat exchange efficiency.

The circular cross-sectional design further optimizes fluid distribution. In regenerative combustion systems, flue gas and air alternate through the honeycomb channels; the circular geometry minimizes flow dead zones, ensuring uniform heat transfer. For example, in steel heating furnaces, circular honeycomb heat storage units keep furnace temperature deviations within ±15°C, increase product yield by 12%, and reduce oxidation burn-off by 30%.

### Preparation Process: Synergistic Precision Forming and High-Temperature Sintering

The production of corundum–mullite honeycomb ceramic heat-storage elements involves multiple precision processing steps. Raw-material proportioning is critical: high-purity corundum powder (particle size <5 μm), mullite powder (particle size <10 μm), and a binder are mixed in specific ratios, followed by wet ball milling to ensure a uniform particle-size distribution. The resulting slurry is then extruded and formed into cylindrical honeycomb green bodies using a vacuum kneading machine. During this process, the extrusion pressure must be precisely controlled within the range of 8–15 MPa to prevent deformation of the pore channels.

Green bodies are dried using a combined microwave–infrared technique, with gradient heating at a rate of no more than 0.3°C/h to prevent cracking. Final sintering is carried out at a high temperature of 1650°C for a holding time of up to 10 hours, ensuring thorough densification and achieving a bulk density of 3.0 g/cm³ or higher. Post-sintering treatments, including grinding and cleaning, are performed to ensure dimensional accuracy meets the specified tolerances—for example, for a Φ150 × 300 mm specification, the tolerance is controlled within ±0.5 mm.

### Application Scenario: A Model for Energy Conservation and Emission Reduction Across Multiple Industries

1. **Steel Industry**: In pusher-type reheating furnaces, circular honeycomb regenerators have increased flue-gas waste-heat recovery to 85%, achieved air preheating temperatures of 550°C, and reduced fuel consumption by 64%. A retrofit project for a copper smelting furnace demonstrated that, after adopting a stratified arrangement of circular honeycomb regenerators, the flue-gas outlet temperature was reduced from 850°C to 180°C, with NOx emissions decreasing by 25%.

2. **Glass Manufacturing**: When this material is used in glass melting furnaces, melting efficiency increases by 20%, and natural gas consumption decreases by 18%. Its low thermal expansion properties effectively mitigate the erosive effects of molten glass on the furnace lining, thereby extending equipment service life.

3. **Chemical Industry**: In regenerative thermal oxidizers (RTOs), circular honeycomb heat storage units can withstand the high-temperature shocks generated during the decomposition of organic waste gases, achieving a thermal efficiency of over 95% and reducing VOC treatment costs by 40%.

4. **Environmental Protection and Governance**: After the material was adopted in waste incinerators, dioxin emission concentrations decreased from 0.1 ng-TEQ/m³ to 0.02 ng-TEQ/m³, meeting EU standards.

### Market Outlook: Sustained Growth Driven by Technology

According to industry reports, the global honeycomb ceramic heat-storage-body market is projected to expand at a compound annual growth rate of 7.8%, reaching US$1.182 billion in 2032. Among these, corundum–mullite materials are gaining increasing market share in the high-end segment due to their outstanding high-temperature resistance. As the world’s largest consumer, China’s production reached 620,000 tonnes in 2025, accounting for 83% of global output, and the country is leading technological breakthroughs in innovative areas such as silicon carbide-based composites.

In the future, with the application of 3D printing technology in the fabrication of honeycomb structures, pore-wall accuracy is expected to be improved to ±0.05 mm, while the specific surface area will increase by an additional 15%–20%. Meanwhile, the development of a zirconia-toughened mullite system will enhance the material’s fracture toughness by 50%, meeting the demands of ultra-high-temperature service conditions up to 1,700°C. Corundum–mullite honeycomb ceramic heat-storage elements (cylindrical type) are driven by both materials innovation and structural optimization, continuously propelling a green revolution in industrial thermal-energy utilization.