Detailed explanation
The electric arc furnace is an important technology in modern steel production. Especially for the recycling of steel scrap.
Traditional blast furnaces produce pig iron from ore. The electric arc furnace is more flexible in terms of the materials used. It is also more environmentally friendly as it uses recycled materials.
The principle of an electric arc furnace is based on the use of electric current. This is passed through graphite electrodes to create an electric arc. This arc can reach temperatures of up to 3,500 °C. This melts the steel scrap within 25 to 40 minutes.
The resulting molten metal reaches temperatures of up to 1,800 °C. After the melting process, the molten steel is tapped, whereby typical tapping weights can be between 80 and 120 tonnes. The largest electric arc furnaces are even capable of holding up to 250 tonnes of steel.
Different types
There are two main types of electric arc furnaces: three-phase and direct current furnaces. In Europe, three-phase furnaces with three graphite electrodes are particularly common. They account for around 90 per cent of the capacity of electric arc furnaces.
DC furnaces have a graphite electrode in the lid and a bottom anode in the hearth and are known for their low power losses. However, they are being used less and less, as modern three-phase furnaces have inherited many of their original advantages and have better load distribution.
Efficiency and quality
Energy efficiency and the quality of steel produced depend largely on the quality of the scrap or sponge iron used. An electric arc furnace consumes around 350 to 400 kWh of electricity per tonne of steel. It has a typical connected load of around 120 MW. The actual consumption also depends heavily on the quality of the scrap, the process optimisation and the additives used.
Renewable energies and the future of electric arc furnaces
Electric arc furnaces (EAF) offer a unique opportunity to make steel production more climate-friendly. By using renewable electricity, these systems can be operated almost CO₂-free, which significantly increases their importance in the context of the energy transition. Especially in combination with sponge iron from hydrogen-based direct reduction, the electric arc furnace is becoming a key technology for the decarbonisation of the steel industry.
This approach not only enables the utilisation of recycled materials such as steel scrap, but also the processing of sponge iron produced in a climate-neutral way. This makes electric arc furnaces a central component of sustainable and future-orientated steel production.
