New Energy-saving DC Electric Arc Furnace

1. Basic Equipment Structure

1. Electrode Configuration: The mainstream design adopts single top graphite electrode plus furnace bottom anode; the updated dual-electrode design without bottom anode effectively avoids furnace bottom burn-through. Compared with 3-electrode layout of AC furnaces, the electrode auxiliary structure is greatly simplified.
2. Power Supply Upgrade: The latest generation is equipped with IGBT flexible rectifier power supply, an upgraded version of traditional thyristor power supply. It realizes full-digital closed-loop regulation, stepless voltage & current adjustment and online polarity switching without shutdown, supporting both submerged-arc and open-arc smelting modes for dual-purpose of arc furnace and submerged arc furnace.
3. Intelligent Automatic Control: The PLC system enables one-key switching among constant power / constant current / constant voltage smelting modes. Soft start prevents power grid impact, with full protection against overvoltage, overcurrent, phase loss and overtemperature.

2. Core Energy-saving Technical Indicators (vs. Conventional 3-phase AC EAF)

3. Fundamental Energy-saving Mechanism

1. Reduced Circuit Loss: Alternating current induces alternating magnetic field and eddy heat loss; constant DC magnetic field eliminates eddy heating on short-net cables to cut invalid power waste.
2. Stable Arc Combustion: DC current has no zero-cross point, maintaining continuous arc without intermittent extinction to improve thermal efficiency via concentrated directional heat input.
3. Built-in Electromagnetic Stirring: DC current forms fixed-direction magnetic field to drive circulating molten bath, eliminating extra power-consuming external electromagnetic stirring equipment and accelerating raw material melting.
4. Flexible Power Regulation: Modular IGBT rectifier outputs precise power on demand; intelligent current limiting during scrap collapse and impact-free arc reignition prevent instantaneous peak power waste.

4. Applicable Smelting Materials

1. Ferrous Metallurgy: Scrap steel melting for carbon steel, stainless steel, alloy steel, bearing steel, die steel and pig iron production; short-process EAF steelmaking cuts around 1.6 tons of CO₂ emission per ton of scrap processed.
2. Ferroalloy & Non-ferrous Metallurgy: Production of ferrosilicon, ferrochrome, ferromanganese, calcium aluminate, red mud-based iron smelting and precious metal refining.
3. Solid Waste Recycling: Melting treatment of fly ash, metallurgical slag and hazardous solid waste for resource recovery, realizing multi-purpose single equipment.

5. New-generation Technical Advantages

1. Reversible Polarity Technology: Real-time anode-cathode switching during smelting evens out furnace temperature distribution to eliminate overheating or cold zones, further lowering power consumption and improving finished product yield.
2. Integrated Scrap Preheating System: Flue gas waste heat recovers to preheat incoming scrap, saving another 20~35kWh power per ton of steel.
3. Digital Smelting Control: Real-time collection of arc voltage, arc current and furnace temperature data; AI self-adaptive power curve optimizes energy consumption to comply with low-carbon steelmaking policies.

6. Application Advantages & Industry Trend

• Capital & O&M Cost: Lower investment on matching electrodes, short-net cables and reactive power compensation facilities; comprehensive operating cost 18%~25% less than conventional AC furnaces.
• Policy Compliance: Short-process EAF steelmaking is core route for domestic low-carbon steel transformation; energy-saving DC furnaces are prioritized for scrap recycling and dual-carbon compliant projects in special steel & renewable metallurgy sectors.
• Full Size Range: Complete product lineup from 0.5t lab-scale furnace, 5t/10t/20t industrial furnace up to hundred-ton large-scale steelmaking furnace.