Slag resistance

In order to improve the material's slag resistance and molten steel penetration resistance, Cr is usually added to corundum spinel breathable bricks.2O3Or add part of chrome corundum.Cr2O3and a-Al2O3have the same crystal structure, Cr2O3It not only improves the slag resistance of the material, but also increases the wetting angle between the material and the molten steel, which significantly improves the blockage of the pores of the breathable brick due to the penetration of the molten steel.

Utilize Cr2O3Fine powder and Al2O3The aluminum-chromium solid solution and the independent chromium-containing glass phase formed at high temperature form a liquid phase with a certain viscosity when in contact with the slag in the molten steel smelting process, thereby hindering the erosion of the slag in the molten steel to the breathable brick; at the same time, it can absorb the slag The iron oxide and magnesium oxide in the air-permeable brick form dense spinel in the working layer of the air-permeable brick, which improves the slag resistance of the air-permeable brick.

But adding Cr to the material2O3, after high temperature firing or use, Cr3 plusoxidized to Cr6 plus,Cr6 plusIt is toxic and will pollute the environment. Therefore, in order to save energy and protect the environment, the use of Cr should be avoided as much as possible.2O3, and by replacing the raw materials, so that no Cr is added2O3The high temperature performance after the addition of Cr2O3level of time.

Thermal shock resistance

The main damage method of breathable brick is thermal shock damage. With the continuous increase of tapping temperature,breathable brickThere is a large temperature difference between the working surface and the intermittent working surface of the working surface, which requires the material to have extremely high thermal shock resistance. The introduction of spinel phase into the castable will improve the thermal shock resistance of the breathable brick.

The oxide or non-oxide added to the breathable brick forms a solid solution phase with the aggregate at high temperature, which increases the high temperature strength of the brick, improves the permeability of the brick, and resists the erosion of the slag in the ladle to the breathable brick. After the brick is heat treated at high temperature, its performance is improved to meet the requirements of its use.