What Are the Requirements for Raw Materials in Electric Arc Furnace Steelmaking?

 

Electric arc furnace steelmaking is a steelmaking method that uses electricity as a heat source, heating and melting metal through an electric arc generated between graphite electrodes and the furnace charge. 

This method allows for precise control of the furnace atmosphere and strong control over the steel composition, enabling the production of not only ordinary carbon steel but also special alloy steels such as tool steel and spring steel.

Steelmaking electric furnaces can also be used to smelt iron ore, making them widely applicable in steel production. Therefore, they have relatively flexible requirements for raw materials, but the characteristics of the raw materials directly affect smelting efficiency, steel quality, energy consumption, and production costs. The main requirements are as follows:

Raw Material Requirements for Electric Arc Furnace Steelmaking

1. Types & Forms of Raw Materials

• Scrap Steel: The main raw material, typically accounting for 70%-100%. Clear classification is required to avoid contamination with harmful elements.
• Direct Reduced Iron (DRI/HBI): As a supplement or substitute for scrap steel, it can reduce the content of residual elements, but the content of iron oxide and gangue must be controlled.
• Pig iron/molten iron: Can partially replace scrap steel, providing physical and chemical heat and shortening smelting time, but sulfur and phosphorus content must be controlled.
• Alloy materials: Used to adjust the composition of molten steel (e.g., chromium, nickel, manganese), requiring stable composition and moderate particle size.
• Slag materials: Lime, fluorite, etc., used for slag formation, requiring appropriate purity and particle size.

2. Chemical Composition Requirements

Hazardous element control:

• Residual elements (Cu, Sn, Ni, Cr, Mo, etc.): Residual elements in scrap steel cannot be removed by oxidation and must be strictly classified (e.g., avoiding mixing with automotive scrap steel and electronic waste).
• Phosphorus (P) & sulfur (S): High-phosphorus and high-sulfur scrap steel needs to be mixed with low-phosphorus molten iron or DRI, or treated through an enhanced dephosphorization process.
• Heavy metals (Pb, Zn, etc.): Easily volatile and accumulate in the electric furnace, requiring pre-removal (e.g., scrap steel preheating treatment).
• Carbon content: The carbon content of scrap steel must meet the carbon blending requirements; if insufficient, carbon additives are needed.

3. Physical State & Dimensions

• Density and Bulk Density: A high proportion of light, thin materials (such as car shells and cans) will reduce the charge density, affecting heat transfer efficiency and arc stability. Packing or briquetting is necessary.
• Block Size:

Too large (e.g., heavy scrap): Slow melting, may impact the EAF furnace lining.

Too small: Prone to oxidation, increased burn-off, and may be drawn away by the flue gas system.

Ideal Size: Generally, the side length should be ≤ 1/3 of the furnace diameter.

• Cleanliness:

Explosives and sealed containers are strictly prohibited (may cause explosions).

Reduce organic impurities such as oil, rubber, and plastics (increase energy consumption and flue gas pollution).

Avoid large amounts of non-metallic impurities such as mud, sand, and refractory materials (increase slag volume and energy consumption).

4. Batching Requirements

• Economics: Dynamically adjust the proportions of scrap steel, DRI, and molten iron according to market prices.
• Melting Characteristics: Appropriately combine light and heavy scrap steel to ensure uniform melting within the EAF steelmaking electric furnaces.
• Endpoint Control: Carbon content must consider the decarburization requirements during the oxidation period to provide conditions for foam slag operation.

5. Pretreatment Requirements

• Scrap Preheating: Preheating scrap steel using waste heat from flue gas (e.g., the Consteel process) can reduce power consumption, but the generation of pollutants such as dioxins must be controlled.
• Rust Removal: Severe rust increases iron loss and slag volume.
• Crushing & Sorting: Mechanized sorting improves raw material purity, especially for removing non-ferrous metals.

6. Adaptability to Smelting Processes

• Requirements for Different Steel Grades:

Ordinary Carbon Steel: Relatively lenient requirements for raw materials.

High-Quality Steel (Bearing Steel, Spring Steel, etc.): Requires raw materials with low residual element content (e.g., high-quality scrap steel, DRI).

• Electric Arc Furnace Type:

Ultra-High Power Electric Arc Furnaces: Requires a high raw material bulk density to improve thermal efficiency.

DC Electric Arc Furnace: Requires higher uniformity in scrap steel block size.

The Core Principles of EAF Steelmaking Raw Materials:

1. Controllable composition: 

Ensuring residual elements and impurities do not exceed the allowable range for the steel grade.

2. Efficient melting: 

Using raw materials with appropriate density and size to reduce melting time and power consumption.

3. Safety and stability: 

Eliminating explosives and sealed containers to prevent furnace splashing or lining damage.

4. Economic & environmentally friendly: 

Reducing costs and pollutant emissions through optimized batching.

Modern electric arc furnace steelmaking tends to use a mixed raw material model of scrap steel + molten iron (or DRI), and relies on intelligent batching systems for dynamic optimization to achieve efficient, low-consumption, and high-quality production. 

If you have any needs or questions regarding steelmaking electric furnaces, refining furnaces, submerged arc furnaces, or other melting furnaces for steelmaking, please feel free to contact us for further solutions.

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

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

Website: www.srfurnace.com / www.srmeltingfurnace.com / 

Xi'an Sanrui Electric Furnace