Double electrode DC arc furnace with World's leading technology/invention patents

Basic Structure & Working Principle

• Core Components: Two graphite electrodes (cathode + anode), DC power supply (thyristor rectification), furnace body (water-cooled furnace cover/wall, refractory lining), electrode lifting mechanism, and optional bottom anode (for some configurations).
• Working Principle: DC current flows from the anode electrode through the molten bath to the cathode electrode, forming two arcs (one between each electrode and the bath). It avoids the complex design of single-electrode DC EAF bottom anodes and is easy to retrofit from AC furnaces.
• Arc Characteristics: Arcs are stable and concentrated, with a deflection angle of 15°–30° toward the bath; electromagnetic force causes the arc to rotate around the center (several times per second), ensuring uniform heating.

Key Technical Parameters (Typical Ranges)

Core Advantages vs. Traditional Furnaces

1. Arc Stability & Uniform Heating: No arc flicker; electromagnetic stirring of the bath eliminates hot spots, reducing lining erosion by 20%–30%.
2. Low Energy & Electrode Consumption: Power consumption is 5%–10% lower than AC EAF; electrode consumption is reduced by ~50% compared to AC EAF (single-electrode DC EAF level).
3. Grid-Friendly: Smaller voltage fluctuations and reactive power changes; DC reactor suppresses inrush current, suitable for areas with weak grids.
4. Flexible Retrofit: No need for complex bottom anodes; existing AC furnace vessels can be converted to DE-DC EAF at low cost.
5. Low Noise: Melting noise is ~87dB (15dB lower than AC EAF), with mainly high-frequency components that are easy to isolate.

Application Scenarios

1. Special Steel Smelting: Bearing steel, low-carbon stainless steel, heat-resistant steel; high alloy recovery rate (≥96% for Ni/Cr/Mo).
2. Non-Ferrous Metallurgy: Magnesium smelting (DC submerged arc furnace), copper/nickel alloy smelting; stable operation and large crystal grains.
3. Metal Recycling: Scrap steel, smelting waste residue, and rare metal recovery; strong adaptability to raw materials.
4. Refractory Metal Processing: Melting of tungsten/molybdenum alloys (with auxiliary plasma heating).

Typical Configuration & Operation Notes

• Electrode Configuration: Two top electrodes (cathode + anode) are standard; some large furnaces add 2–4 water-cooled bottom anodes to balance current distribution.
• Power Supply System: Thyristor rectifier + DC reactor; arc length is automatically adjusted by the electrode lifting mechanism to stabilize power input.
• Cooling System: Total water flow rate of 10–500m³/h, water pressure of 0.3–0.6MPa, and conductivity ≤50μS/cm to prevent electrode overheating.
• Atmosphere Control: Optional argon/nitrogen sealing to reduce oxidation and improve alloy recovery.

Comparison with Other Furnace Types

Development Trends

1. Ultra-High Power: Large-scale furnaces (e.g., 420t) adopt dual-cathode + multi-bottom anode configurations to improve power density.
2. Energy-Saving Technology: Combined with oxygen-fuel combustion and waste heat recovery, energy consumption is reduced by 10%–15%.
3. Intelligent Control: AI-based arc length and temperature control systems to optimize smelting cycles.
4. Environmental Protection: High-efficiency dust removal (emission concentration ≤10mg/m³) and low-NOₓ operation.

Summary