The biggest difference between tabular corundum and white corundum lies in their crystal structure and density—a fundamental distinction that directly drives differences in performance, production processes, and application scenarios. Below is a detailed breakdown:
1. Core Distinction: Crystal Structure & Density
- Tabular corundum: Features well-developed, flat plate-like crystals with tight interparticle packing. Produced via high-temperature sintering (≥1800°C), it has ultra-high density (low porosity, typically <5%) and minimal internal defects (e.g., cracks, pores) in its crystal structure.
- White corundum: Has angular, granular (or blocky) crystals with incomplete development. Manufactured by electric fusion (arc furnace melting followed by cooling), it has lower density (higher porosity, around 8-12%) and is prone to tiny pores or microcracks within the crystals.
2. Derived Differences in Key Properties
| Property Category | Tabular Corundum | White Corundum |
|---|---|---|
| High-temperature stability | Excellent: Maintains structural stability without softening/deformation at 1800°C+; uniform low thermal expansion. | Good: Similar melting point (~2050°C) but prone to slight deformation at ultra-high temperatures due to internal defects. |
| Corrosion resistance | Superior: High purity (Al₂O₃ ≥99%) + dense structure resists molten metal/slag erosion and penetration. | Moderate: Purity (Al₂O₃ ≥98%) slightly lower; granular structure allows easier melt penetration, leading to faster wear. |
| Thermal shock resistance | Outstanding: Plate-like crystals buffer thermal stress, minimal strength loss after temperature cycles. | Average: Granular crystals have poor stress absorption; prone to cracking/spalling under frequent temperature changes. |
| Mechanical strength | Higher: Superior compressive and wear strength at room/high temperatures; dense brick structure. | Lower: Inferior strength compared to tabular corundum; more susceptible to mechanical damage. |
3. Differentiated Application Scenarios
- Tabular corundum: Targets high-end refractory bricks for harsh industrial environments (e.g., steel converters, glass melting furnaces, cement rotary kiln burning zones). Core demand: long service life and resistance to extreme conditions.
- White corundum: Used in mid-to-low-end refractories, abrasive tools (e.g., sandpaper, grinding wheels), or general-purpose refractory materials. Focus: cost-effectiveness for mild working conditions (e.g., ordinary kilns, non-critical furnace linings).
