High purity corundum brick is widely used as the lining material of residuum gasifier, coal gasifier, carbon black reactor, pulp waste liquid gasifier and other industrial furnaces due to its excellent corrosion resistance, wear resistance, high temperature strength, load softening temperature, creep and other thermodynamic properties.
In the process of producing high purity corundum bricks, white fused corundum and plate corundum are the main raw materials. Their low content of impurities (such as SiO2), high volume density and good thermodynamic properties make corundum bricks resistant to thermal, chemical and structural damage caused by the operation of gasifier and other industrial furnaces. So which of these two raw materials is the most suitable for the production of high purity corundum brick?
First of all, the production process and properties of white fused corundum and plate corundum are different, which makes the performance and use of corundum brick have certain differences. Plate corundum has been widely used in the production of high performance refractory materials for steelmaking, such as sliding spout,Al2O3-MgO-C bricks, castables and prefabricated parts. For a long time, the raw material of high purity corundum bricks used in non-steel industry, such as gasifier and other industrial furnaces, is mainly white fused corundum. It is generally believed that the high volume density of fused white corundum can improve the density of products, and its good corrosion resistance can improve the comprehensive performance of products.
Secondly, from the aspect of volume density comparison, the volume density of white fused corundum is slightly lower than that of plate corundum, and the porosity of the opening is significantly higher, up to 8.8%. Plate corundum has low open porosity (only 2.9%), no obvious open porosity, but mostly closed porosity or intergranular porosity, the size is usually less than 10μm, and evenly dispersed in the particles.
Furthermore, considering the firing shrinkage of slab corundum brick, it can be considered that the better thermodynamic activity of slab corundum is beneficial to the densification of firing, so that the brick whose aggregate is completely made of slab corundum can be fully sintered at a relatively low temperature, which is beneficial to cost saving.
Plate corundum can not only improve the corrosion resistance, but also improve the permeability resistance. The low apparent porosity, high volume density and good ceramic bonding are the reasons for the good permeability resistance of the brick containing plate corundum.
Tabular corundum brick can improve the performance of corundum brick, especially the comprehensive performance, which can be summarized as follows:
1. Corundum brick containing plate corundum has better sintering activity, which can improve the densification degree of corundum brick;
2. Corundum brick containing plate corundum has high volume density and low apparent porosity;
3. Pure plate corundum brick has high room temperature compressive strength, room temperature bending strength and high temperature bending strength;
4. Plate corundum brick has the best wear resistance;
5. Corundum brick containing plate corundum is better than pure electric white fused corundum brick in resisting the erosion and penetration of coal gasification furnace slag and residue.
6. The thermal shock stability of corundum brick can be improved by using plate corundum and fused white corundum as aggregate.
7. The creep resistance of pure plate corundum brick and pure white fused corundum brick is better than that of the corundum brick using their composite aggregate.
To sum up, the performance of corundum brick using plate corundum as aggregate is better than that using electric white fused corundum as aggregate, and importantly, the performance of corundum brick using plate rigidness is better in many aspects.
