Why does electric arc furnace steelmaking consume high electricity?

Electric arc furnace is a furnace for smelting ore and metal at high temperature generated by electrode arc. When gas discharge forms arc, the energy is very concentrated, and the arc temperature is above 3000 ℃. For smelting metal, electric arc furnace has greater process flexibility than other steelmaking furnaces, can effectively remove impurities such as sulfur and phosphorus, easy to control furnace temperature and small equipment floor area, which is suitable for smelting high-quality alloy steel.

Reasons of power consumption in EAF furnace steelmaking 

Electric arc furnace steelmaking takes precious electric energy as the main energy. The reasons for power consumption are actually composed of many aspects, mainly including the operation of raw materials, objective conditions and other influencing factors.

1. Raw material conditions

For scrap steel used in electric arc furnace steelmaking, light and thin materials and briquettes are required to be used as raw materials, which is often easy to cause high material feeding and hot shutdown, resulting in large heat loss. In case of insufficient primary loading, secondary feeding is required. In some cases, there have been three feeding, which also increases the heat loss. The power consumption increases by about 7-12kw·H/T for each additional loading (the average loading time is 5min). In addition, after the raw material is cleaned, it is found that C and P are high. When entering the oxidation period, the removal of C and P will take a long time and high energy consumption.

2. Operator skills

The power consumption in melting period accounts for 60% - 70% of the total power consumption, and the power is mainly wasted after chemical cleaning. The most common phenomenon is the blind slag flow in the dephosphorization process in oxidation period, which wastes a lot of lime and energy.

3. Limitations of objective conditions

In the smelting process, due to the shortage of electric energy, the phenomenon of switching off and power limiting suddenly occurs. Over time, the molten steel needs to be remelted after cooling and solidification, which wastes a lot of electric energy.

4. Other accidents

If the operator breaks the electrode due to improper operation, a large amount of heat will be lost in the process of treating the electrode. When the reducing sample is taken in the reduction period, it is found that the composition is unqualified, secondary oxidation must be carried out, and a large amount of heat energy will be wasted. During the smelting process, the coal oxygen burner leaks water, resulting in the interruption of melting aid; when hanging the material on the furnace wall, the furnace cover needs to be turned off for treatment, which can delay smelting time and increase the heat loss at different degrees.