Electric arc furnace steelmaking using scrap steel as raw materials accounts for 35% of the total steelmaking in the world. Electric arc furnace steelmaking is a process in which electric energy is converted into heat through graphite electrodes.
Introduction to electric arc furnace steelmaking
The world's first electric arc furnace was invented by Frenchman Heroult in 1899. The electric arc furnace steelmaking cycle is 60 minutes, which is a process of remelting and refining scrap steel. Using scrap steel or crude steel as the main raw material, there is no need for a blast furnace steelmaking system using iron ore as raw material.
Electric arc furnace steel industry
The electric arc furnace uses graphite electrodes to generate electric arcs, and the temperature of the arc area is above 3000°C, which is sufficient for smelting metals and ore. What is an electric arc? It can be said to be artificial lightning, which can raise the temperature in the furnace to about 10,000 degrees.
Industrial electric arc furnace is divided into AC electric arc furnace and DC electric arc furnace
AC Electric Arc Furnace
The AC electric arc furnace consists of a furnace cover, a furnace body and an electrode. The furnace cover is movable, the outer ring is made of steel, mostly water-cooled, and the top is made of refractory materials except for the water-cooled ring. There are three electrode holes on the furnace cover, through which three graphite electrodes are inserted into the furnace. The furnace body is composed of the furnace bottom, the furnace slope and the furnace wall, and is built with refractory materials, and is wrapped with a steel furnace shell. One side of the furnace wall is provided with a furnace door, and the other side is a tapping port connected with the tapping trough. The most commonly used AC electric arc furnace is the ultra-high power electric furnace (UHP-EAF), which has short steelmaking time, low power consumption and stable arc.
DC Electric Arc Furnace
DC electric arc furnace is a new type of smelting electric arc furnace. Like the AC electric arc furnace, it uses the electric arc generated between the electrode and the charge to generate heat, but only one graphite electrode is the anode on the top of the furnace, and the other cathode is embedded at the bottom of the electric furnace; it can reduce the amount of refractory materials and save power consumption, but The furnace bottom is more complicated and the maintenance cost is higher.
As the demand for AC electric arc furnace capacity and power increases, the stability of AC arc is poor, the impact on power supply equipment is greater, and there are problems such as greater noise, while large-scale DC arc furnaces have larger capacities from 60t to 180t, stable DC arcs, and noise Small and low electrode consumption.
Electric arc furnace steelmaking process
The production process of electric arc furnace steelmaking: slagging and repairing furnace, loading metal charge, power transmission, melting, oxidation, reduction refining and steel tapping. Flow chart of electric arc furnace steelmaking production