An electric arc furnace is an electric furnace that smelts metals and ore at high temperatures generated by electrode arcs. When the gas discharge forms an arc, the energy is very concentrated, and the temperature of the arc zone is above 3000 ℃. For smelting metals, electric arc furnaces are more flexible than other steelmaking furnaces. They can effectively remove impurities such as sulfur and phosphorus. The furnace temperature is easy to control, and the equipment occupies a small area. It is suitable for the smelting of high-quality alloy steel. 

Classification of electric arc furnaces

According to the heating method, the electric arc furnace can be divided into three types: indirect heating, direct heating and submerged arc.

1. The indirect heating electric arc furnace is an electric arc generated between two electrodes. It does not touch the material and heats the material by thermal radiation. This kind of furnace is noisy, low in efficiency, and gradually eliminated.

2. The direct heating electric arc furnace is an electric arc generated between the electrode and the material to directly heat the material. The three-phase electric arc furnace for steelmaking is the most commonly used direct heating electric arc furnace.

   3. Submerged arc circuit is also called reduction electric furnace or submerged electric furnace. One end of the electrode is buried in the material layer, an arc is formed in the material layer, and the material is heated by the resistance of the material layer itself. It is commonly used for smelting ferroalloys, smelting matte, matte, and producing calcium carbide. 

The working principle of electric arc furnace 

Electric arc furnace smelting uses the heat generated by the arc generated between the graphite electrode and the iron material (liquid iron) to melt the iron material and overheat the liquid iron. In the electric arc furnace smelting process, after the iron material is melted, the smelting operation to further increase the temperature and adjust the chemical composition is carried out under the condition that the molten iron is covered by the molten slag. Electric arc furnaces are classified into acidic and alkaline according to the properties of slag and refractory lining. The alkaline electric arc furnace has the capability of desulfurization and dephosphorization. 

Advantages and disadvantages of electric arc furnace

1. The advantage of electric arc furnace smelting is that it has a strong ability to melt solid charge, and the molten iron is overheated and adjusted chemical composition under the condition of slag covering, so it can avoid the absorption of molten iron and the oxidation of elements to a certain extent. This creates good conditions for smelting low-carbon cast iron and alloy cast iron.

2. The disadvantage of the electric arc furnace is that it consumes a lot of electric energy, and it is not as economical as the cupola from the perspective of melting. Therefore, the cupola-electric arc furnace duplex method is often used in the production of cast iron. Because the alkaline electric arc furnace lining has poor resistance to rapid cooling and heating, under intermittent smelting conditions, the lining life is short, resulting in high smelting costs, so acid electric arc furnaces are often used in conjunction with cupola furnaces.