Classification of breathable bricks (3)

(Picture) GW series slit type breathable brick

Permeable bricks can be divided into corundum-spinel system ventilation bricks, corundum-chromium oxide system ventilation bricks, corundum-spinel system ventilation seat bricks and corundum-chromium oxide system ventilation seat bricks according to their materials.

1 Corundum-spinel system breathable brick

Because the slag resistance and thermal shock resistance of single-phase corundum castables are not ideal, the spinel material has good slag erosion resistance. Therefore, high-purity fused spinel is added to the corundum castable to achieve the purpose of improving the performance of the corundum castable. The raw material is mainly plate-shaped corundum, and the air-permeable bricks fired at high temperature with binder have good thermal shock resistance and slag resistance.

2 Corundum-Chromium Oxide System Breathable Brick

In order to further improve the resistance to steel slag corrosion of the air-permeable brick, a certain amount of chromium oxide micropowder is added to the composition. The main raw material is plate-shaped corundum, and chromium oxide is added to the corundum castable. At high temperatures, chromium oxide and aluminum oxide form high-temperature solid solutions, and at the same time form a partial solid solution MgO·Cr2O3-MgO·Al2O3 with a small amount of magnesium oxide. The viscosity of this solid solution is very high, and the corrosion and resistance to Fe2O3 or slag are significantly enhanced, so that the penetration and corrosion of steel slag can be effectively prevented at high temperatures. At the same time, a small amount of Cr2O3 can also inhibit the excessive growth of Al2O3, reduce the stress in the crystal, and improve the physical properties of the material. However, if the amount of addition is too large, the growth of corundum grains will be excessively inhibited, and internal stress will also be generated, thereby reducing the physical properties of the material. In addition, the price of Cr2O3 is relatively high, adding too much will greatly increase the cost, and will have a certain impact on the environment.

3 Corundum-spinel system breathable seat brick

The corundum-spinel system breathable seat brick is the most widely used material, and the main raw material is corundum. The advantage is that spinel has relatively strong resistance to acids and alkalis, and is a high melting point compound with good performance. The aluminum-magnesium spinel has strong resistance to alkaline slag, and has a relatively stable effect on iron oxides. When it comes in contact with magnetite at high temperatures, it will react to form a solid solution, and the high-temperature corrosion resistance of the breathable seat brick can be improved; At the same time, solid solution MgO or Al2O3 spinel has better thermal shock resistance due to the difference in expansion coefficient between minerals.

4 Corundum-Chromium Oxide System Breathable Block

The corundum-chromium oxide system breathable seat brick is produced on the basis of the corundum-spinel system in order to improve the high temperature resistance of the breathable seat brick. The main raw material is tabular corundum, and a small amount of industrial chromium oxide powder is added. The advantage is that on the basis of improving the performance of the bricks by spinel, the solid solution formed by Al2O3-Cr2O3 has a significant increase in corrosion resistance to iron oxide slag. Adding less Cr2O3 can inhibit the excessive growth of alumina crystals, thereby reducing the internal crystals. Stress, improve the thermal shock resistance, erosion resistance and erosion resistance of the breathable seat brick.

Concluding remarks

No matter how harsh the on-site use conditions are, through past use experience and on-site experimental analysis, we will surely be able to find a kind of breathable brick that meets the requirements of the on-site smelting process.