Bubble Alumina for Castable
Refractory products made of hollow spheres have good high-temperature resistance, good insulation properties, good thermal shock resistance, and high strength. Since those materials have low bulk density and low thermal capacity, they can improve the thermal efficiency of high-temperature furnaces, shorten the production cycle and significantly reduce the furnace’s weight. It can be directly used in the linings of high-temperature furnaces.
Manufacturing Process – Bubble Alumina for Castable
Alumina raw materials are melted in an electric arc furnace at 2200℃. When pouring the melt out, blow the melt with high-pressure air to make the melt dispersed into small droplets. During the cooling process, the droplets form alumina hollow balls due to surface tension effects. The hollow balls are screened to remove fine powder and big fragments and particles. Iron is removed with the magnetic iron. Broken balls are removed with a ball selecting machine. Then the alumina hollow spheres are packed as the finished products.
| TYPICAL PHYSICAL PROPERTIES | |
| Crystallography | Alpha alumina, in the hexagonal crystal system |
| Color | White |
| Shape | Spherical shaped hollow bubbles |
| Average crystal size | 2,500 microns, no matrix |
| Typical Anaysis | |
| Al2O3 | 0.988 |
| SiO2 | 0.008 |
| MgO | 0.0005 |
| Na2O | 0.001 |
| Fe2O3 | 0.0003 |
| CaO | 0.003 |
| Sizing | Bulk Density |
| 0 – 0,2 mm | 1000-1450 |
| 0 – 0,5 mm | 800-1100 |
| 0,5 – 1 mm | 650-850 |
| 0 – 1 mm | 700-1050 |
| 1 – 1,5 mm | 550-800 |
| 0 – 2 mm | 650-1000 |
| 1,5 mm – 2 mm | 550-800 |
| 0 – 3 mm | 650-950 |
| 0 – 5 mm | 600-900 |
| 1 – 2 mm | 550-800 |
| 1 – 3 mm | 550-800 |
| 2 – 3 mm | 500-750 |
| 2 – 5 mm | 500-750 |
| 3 – 5 mm | 450-700 |
Edward (verified owner) –
Good service.