Electric Arc Furnace vs Blast Furnace CO2 Emissions

Electric arc furnace vs blast furnace are the two main steel production processes today.

Blast furnaces rely on coke as a reducing agent and heat source, using iron ore as the main raw material, resulting in high carbon emissions and representing a long-process steelmaking process. 

Electric arc furnaces, on the other hand, primarily use scrap steel as raw material, generating heat through an electric arc using graphite electrodes. They do not require coke, have lower energy consumption, and are more flexible, making them suitable for short-process production. Today, let's understand the differences between them and compare their carbon emissions.

Differences between Electric Arc Furnaces and Blast Furnaces

1. Raw Materials & Principles:

• Blast Furnace: Uses iron ore (mainly Fe₂O₃) and coke (C). The core reaction is the reduction of iron ore by coke, a process that directly produces a large amount of CO₂. `Fe₂O₃ + 3CO → 2Fe + 3CO₂`
• Electric Arc Furnace: The main raw material is scrap steel; essentially, it's the recycling and remelting of scrap metal. It avoids the strongly endothermic chemical reaction of reducing iron from ore, thus preventing most of the direct emissions from the process.

2. Energy Structure:

• Blast Furnace: Highly dependent on coal (coke) as a reducing agent and energy source.
• Electric Arc Furnace: Primarily consumes electricity. Its carbon emission intensity is highly dependent on the cleanliness of the local power grid. If the electricity comes from coal-fired power, emissions will increase significantly; if it comes from nuclear power, hydropower, or renewable energy, emissions will be extremely low.

3. Other Differences

• Products: BF produce pig iron that requires further processing; electric arc furnaces directly produce molten steel.
• Energy: Blast furnaces rely on coke combustion; electric arc furnaces rely on electricity.
• Emissions: Blast furnaces emit approximately 1.8-2.2 tons of carbon per ton of steel; EAF emit approximately 0.4-0.6 tons (approximately zero if using green electricity).
• Characteristics: Blast furnaces are suitable for large-scale continuous production; electric arc furnaces are flexible and can be started and stopped at any time.

Relationship between the two:

1. Complementarity: Blast furnace responsible for extracting new resources to meet growing demand; electric arc furnace recycle scrap steel to achieve resource recycling. 

2. Substitution: In regions with abundant scrap steel resources and stringent environmental protection requirements, electric arc furnaces are gradually replacing some blast furnace capacity.

3. Integration: In modern production, scrap steel can be added to the blast furnace process, and electric arc furnaces can also be used with some pure iron raw materials not produced by blast furnaces.

Electric Arc Furnace vs Blast Furnace CO2 Emissions

Process Flow	CO2 Emissions/Ton of Steel (Approximate Value)	Key Explanation
Blast Furnace-Converter Long Process	Approximately 1.8 - 2.2 tons	Using iron ore and coal (coke) as raw materials, chemical reactions produce large amounts of CO₂. This is currently the mainstream steel production method (accounting for approximately 70% of global production).
Scrap Steel-Electric Arc Furnace Short Process	Approximately 0.4 - 0.6 tons	Using recycled scrap steel as raw material, it is smelted and refined using electricity. Emissions mainly come from indirect emissions from electricity production. If green electricity is used, emissions can approach zero.
All-Scrap Steel Electric Arc Furnace (Using Green Electricity)	Can be less than 0.1 tons	Theoretically, when using 100% renewable energy electricity, only small amounts of emissions remain from auxiliary materials and transportation.

Globally, the carbon emissions of the scrap - electric arc furnace short process are approximately one-quarter to one-third of those of the blast furnace-converter long process. 

Developing EAF steelmaking is one of the key technological pathways for the steel industry to achieve carbon neutrality, but its full realization of emission reduction benefits depends on sufficient scrap steel resources and a clean power supply. BF are the foundation of the steel industry, while EAFs are crucial for green transformation. In the future, both will coexist and jointly develop towards low-carbonization.

References:

- IEA (2020), Iron and Steel Technology Roadmap.

- World Steel Association (2022), Life Cycle Inventory Data.

- Metallurgical Industry Planning and Research Institute (2023), "Report on Energy Conservation and Low-Carbon Development of China's Steel Industry".

- China Iron and Steel Association (2022), Related Industry Analysis Report.

 E-mail: alice@srfurnace.com  / Tel: +86 15686041999 (Alice)

E-mail: anna@srfurnace.com  / Whatsapp: +86 159 2955 5868 (Anna)

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Xi'an Sanrui Electric Furnace