Electric Arc Furnace Steelmaking

An electric arc furnace, EAF, melts and refines scrap steel or other metallic feed using heat generated by an electric arc. Compared with the integrated blast furnace-basic oxygen furnace, BF-BOF, route, a scrap-based EAF avoids much of the coal-based conversion of iron ore into metallic iron.

Why direct emissions are lower

In the BF-BOF route, coke and other carbon inputs provide heat and chemically reduce iron ore, producing substantial process carbon dioxide. Scrap already contains metallic iron, so an EAF can bypass ore reduction and the associated blast furnace stage.

• Scrap-based EAF steelmaking avoids most emissions from coke ovens, sinter plants and blast furnaces.
• Its principal energy input is electricity rather than coke, although burners, carbon injection, electrodes and fluxes still cause some direct emissions.
• Recycling steel also avoids much of the energy demand associated with mining, ore preparation and primary ironmaking.

What determines the actual reduction

The climate advantage is greatest when an EAF uses abundant scrap and low-carbon electricity. Its total emissions rise when electricity comes from fossil fuels or when the furnace uses iron made through an emissions-intensive upstream route.

• EAFs may use scrap, direct reduced iron, DRI, or some pig iron; therefore, furnace type alone does not determine lifecycle emissions.
• Gas-based or hydrogen-based DRI can reduce upstream emissions relative to coal-based ironmaking, especially when energy inputs are low-carbon.
• Scrap availability, quality and contamination constrain how much primary steelmaking can be replaced.

Other environmental effects and tradeoffs

Scrap-based EAF production can reduce particulate matter, sulphur oxides, nitrogen oxides and wastewater associated with integrated coke, sinter and blast furnace operations. However, the furnace still produces metal-bearing dust, slag and air emissions that require collection, treatment and safe management.

• EAF steelmaking supports a circular economy by returning end-of-life steel to production.
• Proper scrap sorting is necessary because coatings and unwanted elements can affect emissions and steel quality.
• Emission comparisons should use consistent system boundaries, including electricity generation, scrap processing and production of any DRI or pig iron.