Electric arc furnace: analysis of the advantages of bottom blowing technology

Electric arc furnace: analysis of the advantages of bottom blowing technology.

(1) It promotes the melting of scrap steel and reduces the soft melting phenomenon in the cold zone, in order to help eliminate the cold zone existing in the electric arc furnace steelmaking process.

(2) It is beneficial to increase the reaction rate of the steel slag interface, help the adsorption and removal of inclusions in the electric arc furnace crude steelmaking, increase the reaction rate of dephosphorization and decarburization, and have positive significance for shortening the smelting cycle.

(3) Increase the speed of molten steel in the molten pool, which helps to eliminate the temperature imbalance in the molten pool, and can reduce the tapping temperature.

(4) Due to the stirring effect of the bottom blowing, the reaction at the steel slag interface tends to be more balanced, reducing the iron oxide content in the slag, which is beneficial to the reduction of iron consumption.

(5) As the steel tapping temperature of the electric arc furnace and the iron oxide content in the slag are reduced, the life of the furnace lining is increased.

 When the first furnace is in use, no air is supplied, and the ventilation brick can be replaced when it is seriously damaged. The replacement method is similar to the method of replacing the EBT set of bricks.

Generally, the gas supply pressure is between 0.3-1.2MPa, and the flow rate (standard state) of the stirring gas is controlled at 0.002~0.001m3/(min·t), which has the best effect. The gases used in the bottom blowing are nitrogen, carbon dioxide and argon. Using argon as the bottom blowing gas can reduce the nitrogen content in the steel. In order to reduce costs, some manufacturers use different gas media at different stages. In Oberhause, when producing steel grades that are not sensitive to nitrogen, nitrogen is blown when the molten steel temperature is below 1550°C during smelting, and argon is blown at 1550-1650°C. The temperature of molten steel is below 1550°C, and the amount of nitrogen absorbed by molten steel is small.