Electric Arc Furnace Working Principle, Structure & Advantages

Electric arc furnaces are divided into three categories, working principles are as follows:

1. Direct Heating Type：

The electric arc occurs between the special electrode rod and the smelted charge, and the charge is directly exposed to the arc heat. 

Mainly used for steelmaking, and also used for smelting iron, copper, refractory materials, and refined molten steel.

2. Indirect Heating Type:

The electric arc occurs between two special electrode rods, and the charge is radiated by the electric arc, 

which is used for smelting copper and copper alloys. This kind of furnace is noisy and poor in melting quality and has been gradually replaced by other furnaces.

3. Submerged Arc Furnace:

Uses ore with high resistivity as raw material, and the lower part of the electrode is generally buried in the charge during operation. 

The heating principle is not only the heat generated by the resistance of the charge when the current passes through the charge but also the heat generated by the arc between the electrode and the charge. 

So it's also called Arc Resistance Furnace.

Electric arc furnace uses the high temperature generated by the electrode arc to smelt ores and metals. 

When the gas discharge forms an arc, the energy is very concentrated, and the arc zone temperature is above 3000 ℃. 

For smelting metals, electric arc furnaces are more flexible than other steelmaking furnaces, can effectively remove impurities such as sulfur and phosphorus, the furnace temperature is easy to control, and the equipment occupies a small area, which is suitable for melting high-quality alloy steel.

Electric arc furnace structure, advantages, and working principle

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. 

A three-phase electric arc furnace is commonly used in production, and the structure of the furnace body is shown in the figure below. 

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 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.

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. 

his creates good conditions for smelting low-carbon cast iron and alloy cast iron.

More Article: 
Steel-making Electric Arc Furnace

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