What are the measures to improve the life of the electric arc furnace body?

In the electric arc furnace smelting, the melting period accounts for about 50% of the entire smelting time in the process of fusion oxygen and quick white slag. During the melting process, the SiO2 content in the slag is higher due to the oxidation of Si in the steel material and the sediment adhering to the surface.

In view of the phenomenon that the SiO2 content in the slag during the melting period is relatively high and the alkalinity is low, some measures can be taken, for example, adding light magnesia powder to the furnace before melting and adding lime to the furnace when adding surplus material in the melting period, to increase the content of MgO and the concentration of CaO in slag, reduce the combination of Si02 and MgO, and ensure that there are enough CaO and Si02 phases in slag, so that they can achieve the purpose of protecting the lining refractory bricks.

When the MgO content in the slag is raised again above 1500℃, the carbon element in the refractory bricks and the ferrous oxide in the slag will react with MgO as follows:

MgO+C→Mg (gas)+CO

2FeO+C→2Fe+C02

Mg (gas) + CO2 → MgO + CO

In the above reaction, the magnesia gas diffuses out of the brick, and when it reaches a higher partial pressure of oxygen, it is oxidized to solid MgO. This reaction occurs in succession to form a dense, MgO resistant layer. However, when the magnesia vapor is in direct contact with the oxidizing slag, the following reaction will occur:

Mg (gas) + FeO → MgO + Fe

At this time, MgO is dissolved, causing destruction of the dense MgO layer. If the MgO content in the slag is high, the dense MgO layer can be retained to prevent slag intrusion and prolong the life of the furnace. As the MgO content in the slag increases, the erosion rate decreases and the damage of the lining decreases. To this end, a method of adding calcined magnesia powder to the furnace is adopted to maintain the MgO content in the slag between 8% and 10%, thereby reducing the dissolution of MgO in the lining, thereby achieving the purpose of protecting the lining of the electric arc furnace.