STEEL PRODUCTION AND RECYCLING

In view of climate change and the urgent need to cut greenhouse gases such as CO2, steel is subject to critical debate since its production is often very emissions-intensive. However, alternative production processes and other advantageous properties of steel reinforce our firm conviction:

STEEL IS NOT THE PROBLEM, BUT PART OF THE SOLUTION

Due to its durability and low maintenance frequency, steel is one of the most preferred materials. Compared to other materials such as concrete or timber, however, there is another major advantage that will become even more important in the future: steel can be recycled an infinite number of times without any loss of quality.

LOWER ENERGY USE: Through recycling, the steel industry saves enough energy to supply the annual electricity needs of more than 18 million homes
LOWER CARBON LOADS: Recycling the steel from one car reduces greenhouse gases equivalent to using more than 150 gallons of gasoline

THE SEVEN STEPS OF STEEL RECYCLING

Scrap can be collected from old vehicles, steel structures, railroad tracks, ships, farm equipment, and of course, consumer scrap
Steel needs to be separated from other scrap metals or material waste streams
Steel is then shredded to promote the melting process as small shredded metals have a large surface to volume ratio
Scrap is then melted in a large furnace. But the energy required to melt and recycle is much less than for producing new metals using virgin raw materials
The purification ensures that the final product is of high quality and free of contaminants
After purification, melted steel is carried by the conveyor belt to cool and solidify. In this stage, the steel is formed into specific shapes
Scrap can be collected from old vehicles, steel structures, railroad tracks, ships, farm equipment, and of course, consumer scrap

THE THREE ROUTES OF STEEL PRODUCTION

When people think of the production of steel, they usually have images of blast furnaces in mind. In this energy-intensive process route, pig iron is produced in the blast furnace, which is then processed into crude steel by adding oxygen. An alternative is the production with the electric arc furnace. In this method, recycled steel scrap or sponge iron produced from iron ore is melted into crude steel.

Compared to the conventional blast furnace route, it produces up to 80% fewer carbon emissions. However, as emissions are still caused by this process, there is a growing desire for even more carbon-reduced steel to be produced through the use of renewable energies and green hydrogen.

Iron ore pellets & sinter feed are the iron bearing raw materials. Coke from metallurgical coal is the main energy source. Above listed elements and limestone are added to the BF from the top, while hot air is blasted in from the bottom. The burning coke creates temperatures of ~2000°C extracting hot metal/pig iron from the raw material. The “hot metal” is transformed into steel through oxidation in a basic-oxygen furnace. Often some scrap is added. The resulting liquid steel is cast.
Most EAF mills use scrap as their main input. In regions with competitive gas prices Direct Reduced Iron may also be used. For Direct Reduced Iron - Iron ore and pellets can be reduced in solid state for EAF application. Natural gas is usually used as a reductant. Scrap or direct reduced iron are melted in an EAF at around 3000 °C. Graphite electrodes function as an arc to transform the electrical energy into heat.
In the future steel will have to become 'green'. This can be achieved in two ways. The first is steel from EAF production that uses 100% scrap and is powered with Renewable Energy. Given the finite amount of scrap, steel production via this route is naturally limited. The second way is using 'green' H2 as the reductant for Direct Reduced Iron in an Electric Arc Furnace pathway - (see Electric Arc Furnace).