Electric Arc Furnace (EAF) steelmaking has become a highly flexible, efficient, and environmentally friendly process in modern metallurgy. The quality of steel, melting efficiency, and energy consumption are all closely tied to the selection and preparation of raw materials. Understanding the types of materials used in EAF steelmaking—and how to load them correctly—is essential for achieving stable operation and reducing production costs.
1. Main Raw Materials for Electric Arc Furnace Steelmaking
EAF steelmaking typically uses three major categories of materials:
1.1 Iron-bearing raw materials
These provide the primary metallic charge for melting:
- Scrap steel(light scrap, medium scrap, heavy scrap)
- Pig iron
- Return scrap from internal processes
- Direct Reduced Iron (DRI)
Scrap steel remains the core raw material for EAF steelmaking, and its quality has a direct impact on steel purity, energy consumption, and melting speed.
1.2 Slag-forming materials
Used to build a stable refining slag and control furnace reactions:
- Lime (CaO)– essential for slag formation
- Dolomite (MgO·CaO)– stabilizes slag and protects the refractory lining
- Fluorspar (CaF₂)– improves slag fluidity when necessary
These materials help remove impurities, regulate oxygen potential, and improve thermal efficiency during the melting process.
1.3 Auxiliary materials
Additional materials used during deoxidation, refining, alloying, and slag foaming:
- Foaming agents (carbon powder, coke fines)
- Deoxidizers such as FeSi, SiMn, and aluminum
- Alloying elements for composition adjustment
- Oxidizers (mill scale, iron ore) used in some traditional small furnaces
Each plays an essential role in achieving specific metallurgical objectives inside the EAF.
2. Quality Requirements for Scrap Steel in EAF Steelmaking
To ensure stable melting and high-quality steel, scrap steel should meet the following requirements:
- Clean surface with minimal rust and contaminants
- Free of non-ferrous metals such as lead, tin, arsenic, copper, and zinc
- Clearly known and stable chemical composition
- Appropriate size and block thickness for furnace loading and fast melting
Meeting these criteria reduces operational risks and improves both productivity and steel quality.
3. How to Determine the Proper Scrap Charge for Ultra-High Power (UHP) EAFs
Ultra-high power EAFs offer rapid temperature rise and fast melting speeds. To achieve optimal efficiency, the metallic charge should match the furnace’s transformer capacity and the amount of heel steel left in the furnace.
A commonly used formula is:
Charge Weight < M ÷ 700 – Q
M — Transformer capacity
Q — Heel steel
This formula ensures the charge volume is appropriate for the power level, allowing shorter refining cycles and improved energy utilization.
4. Recommended Loading Sequence for Scrap in an Electric Arc Furnace
Proper layering of scrap steel inside the charge basket helps prevent operational issues such as electrode breakage, slow melting, and furnace-bottom damage.
4.1 Typical loading sequence
| Scrap Type | Placement | Reason |
| Light scrap | Basket bottom | Reduces impact on the furnace bottom |
| Medium scrap | Middle layer | Optimizes thermal distribution |
| Pig iron | Middle–lower layer | High heat capacity; requires strong heat exposure |
| Large scrap pieces | Middle–lower layer | Prevents electrode breakage |
| Heavy scrap | Middle–lower layer | Ensures stable melting and protects electrodes |
4.2 General charging principle
Light scrap (or pig iron) → Medium scrap / Heavy scrap / Slag steel → Additional medium scrap → Light scrap on top
This layered structure improves heat transfer, enhances melting efficiency, and reduces operational risks
