AluChem AC-99 Tabular Aluminas are high-density, fully shrunk, coarse crystalline alpha aluminas that have been converted to the corundum form. Tabular Alumina is produced by sintering ball-formed calcined alumina at a temperature just under the 2040°C fusion point of aluminum oxide. These Tabular Alumina balls are then crushed, graded or screened, and ground to a wide range of granular or powdered particle size distributions.
The typical chemical and physical properties which characterize AluChem’s AC-99 Tabular Aluminas are presented in this product data. Some of these properties are highlighted by the following:
| Chemical purity 2 | 99.5% Al2O3 |
| Chemical inertness | Resistant to most alkalis and mineral acids |
| High density | True density of 3.96 with a bulk specific gravity of 3.55 and an apparent porosity of 4.0% |
| Low water absorption | 1.0% |
| Extreme hardness | 9 on the Mohs' scale and a Knoop hardness of 2,000 |
| High thermal conductivity | @ 100°C 0.069 cal/sec cm °C |
| Good resistance to thermal and mechanical shock | |
| High heat capacity | Specific heat @ 20°C 0.21 cal/gm/°C |
| High electrical resistivity | |
| Excellent abrasion resistance | |
General Characteristics
| Chemical Formula | Al2O3 |
| Bulk Specific Gravity | 3.55 |
| Apparent Porosity | 4.0% |
| Water Absorption | 1.0% |
| Melting Temperature | 2040°C |
| Refractive Index | 1.76 |
| Mohs' Hardness | 9 |
| Appearance | White Crystalline Granules or Powder |
Typical Chemical Composition
| Properties | AC-99 |
| Al2O3, % | 99.5 |
| SiO2, % | 0.04 |
| Fe2O3, % | 0.06 |
| Na20, % | 0.30 |
| L.O.I. (300 - 1200°C), % | 0.00 |
| Alpha Phase | 99+ |
Tyler Sieve Specifications for Standard Products
| Screened Convertor Discharge Balls | Size |
| -3/4 Inch + 1/2 Inch |
| Crushed Sizes | Sieve Analysis |
| 5% Max. On |
| Minus 1/4 Inch | 1/4 Inch |
| Minus 6 Mesh | 6 Mesh |
| Minus 8 Mesh | 8 Meshh |
| Minus 14 Mesh | 14 Mesh |
| Minus 28 Mesh | 28 Mesh |
| Ground Sizes | Sieve Analysis |
| 5% Max. On |
| Minus 48 Mesh | 48 Mesh |
| Minus 60 Mesh | 60 Mesh |
| Minus 100 Mesh | 100 Mesh |
| Minus 325 Mesh | 325 Mesh |
| Minus 325 Mesh | Low Iron 325 Mesh |
| Graded Sizes | Sieve Analysis | Sieve Analysis |
| 2% Max. On | 5% Max. Through |
| 1/4 Inch to 8 Mesh | 1/4 Inch | 10 Mesh |
| 3 Mesh to 6 Mesh | 3 Mesh | 8 Mesh |
| 6 Mesh to 14 Mesh | 6 Mesh | 20 Mesh |
| 8 Mesh to 14 Mesh | 8 Mesh | 20 Mesh |
| 14 Mesh to 28 Mesh | 14 Mesh | 35 Mesh |
| 28 Mesh to 48 Mesh | 28 Mesh | 65 Mesh |
