Conventional steel production is particularly emissions-intensive compared to other sectors and accounts for over a quarter of all industrial emissions. A large proportion of carbon emissions are caused by the smelting (processing) of coke.
Decarbonizing the steel industry is therefore an important lever for a greener future and achieving the Paris climate targets for the benefit of future generations.
The majority of emissions from this conventional production route are generated in the blast furnace through the use of raw materials such as iron ore, coke and gas, which also cause the highest energy consumption.
In the subsequent steel production pig iron is further processed into steel in the converter (BOF - Blast Oxygen Furnace). Hereby, steel scrap is used to cool the process in the converter, with the proportion of scrap used ranging from 15% to a maximum of 25%, depending on the steel producer.
To reduce emissions in this steel production route, carbon can be partially replaced by hydrogen gas. In addition, blast furnace gases, which are a by-product of the smelting process, can be used in a targeted manner to reduce energy consumption.
In order to reduce or even completely avoid emissions from steel production, the European steel industry is currently undergoing a huge upheaval. Steel production is gradually being converted from converters (BOF) to electric arc furnaces (EAF).
This technology enables the use of up to 100% scrap, with the electricity required ideally coming from renewable energy sources.
For the majority of steel producers, the conversion of the steel production route is taking place together with the production of direct reduced iron (DRI) pellets as primary material, which is further processed in the electric arc furnace (EAF). In the direct reduction of iron, iron ore is reduced with a hydrogen-rich gas mixture, resulting in sponge iron. This is then sintered into iron pellets, which are used in steel production.
Electricity and gases are used as energy sources in the overall DRI and EAF processes. There is great potential here for the use of renewable energies for power generation and the production of hydrogen as a reducing agent. The EAF process also enables the processing of up to 100% scrap, which further increases the reduction of emissions in steel production.
