Refractory is an unshaped refractory material which is prepared by ramming (manual or mechanical) method and hardened by heating at a higher temperature.Ramming materials into acid, neutral, alkaline three .
Item | Basic mineral | Crystal system | Crystal color | Mohs hardness | Density |
White aluminum oxide | α- Al2O3 | Hexagonal | White | 9 | ≥3.90g/cm3 |
Item | Micro hardness | Electrical resistivity | Grinding ability(compared with diamond as one) | Linear expansion coefficient(when 900ºC α•10-6k-1) | |
White aluminium oxide | HV2200-2300 | 1014-1016Ω•cm | 0.12 | 8.3 |
Parameter Index
Chemical Composition | Physical Composition |
AL2O3 ≥ 99.5 | Color:White |
Na2O ≤ 0.35 | Mohs Hardness: 9 |
Fe2O3 ≤ 0.1 | Micro hardness: 2200-2300kg/mm2 |
SiO2 ≤ 0.1 | Bulk Density: 3.50g/cm3 |
Melting Point: 2250ºC |
Feature
1.On the face in contact with liquid metal there is a dense sintered layer where tightness of liquid metal is quite perfect.
2.Thermal conductivity is lower than other refractoriness so the Thermal loses are less than any other kind of refractory.
3.Good resistance to temperature change.
4.Low cost in furnace lining.
5.Short heating and sintering time through dry preparation Of masses.