Ferrovanadium DC Furnace: Equipment and Technical Parameters

1. Equipment Overview

2. Complete Equipment System Composition

2.1 Power Supply & Rectification System (Core Power Unit)

1. High-voltage Power Distribution Unit
   
   
   10kV incoming cabinet, isolating switch, vacuum circuit breaker, SVG reactive power filter compensation device; suppresses grid flicker to only 50%~70% of that of AC furnaces.
2. On-load Tap-changing Rectifier Transformer
   
   
   Mainstream capacities: 1800kVA / 2500kVA / 3200kVA
   
   
   Primary side: 10kV; secondary AC output adjustable from 90~220V with multiple tap positions
3. Three-phase Full-controlled Bridge Rectifier
   
   
   High-power thyristor rectifier with closed-circuit water cooling; outputs stable direct current with reversible positive/negative polarity switching; integrated multi-interlock protection against overcurrent, overvoltage, high water temperature and water leakage.
4. Short Network Conductive System

• Upper cathode: water-cooled conductive cross arm, copper contact shoe, single graphite cathode electrode
• Furnace bottom anode: copper conductive base plate, water-cooled conductive support, furnace bottom conductive steel bundles
• Large cross-section internal water-cooled flexible cables with current density ≤3A/mm² to minimize conductive loss

2.2 Furnace Body System

1. Furnace Shell
   
   
   Cylindrical steel plate shell with double-layer circulating water jackets on upper section and thickened water cooling at slag line to reduce erosion from high-temperature radiation; equipped with temperature measuring and water leakage detection sensors.
2. Special Alkaline Refractory Lining for Ferrovanadium Smelting

• Furnace bottom & molten pool: fused magnesia brick, magnesia-carbon brick (withstanding high reduction temperature of 1800~2100℃)
• Slag line furnace wall: chrome-magnesia brick; conductive steel plate laid on furnace bottom as anode
• Tubular fully water-cooled furnace cover reserved with feeding port, flue gas duct and central electrode hole

3. Furnace Tilting Mechanism
   
   
   Full hydraulic bilateral tilting, tilting angle 0~110°, tilting speed 0.5~2°/min; three positioning modes: smelting horizontal position, slag tapping position and metal tapping position, with mechanical locking device.
4. Furnace Cover Lifting & Rotating Device
   
   
   Hydraulic lifting + rotary structure; the cover can rotate away after lifting for furnace patching, slag line cleaning and electrode replacement.

2.3 Hydraulic Electrode Lifting System

1. Single-column hydraulic lifting unit for independent vertical adjustment of single cathode graphite electrode
2. PLC proportional valve dual closed-loop control (constant power regulation via voltage + current), switchable between manual and automatic modes
3. Electrode stroke: 1200~1400mm; lifting response time ≤0.3s to stabilize submerged arc and avoid arc breakage or electrode fracture

2.4 Circulating Water Cooling System

• Independent closed pure water cooling unit for rectifier
• Shared industrial circulating cooling water for furnace shell water jackets, furnace cover, conductive cross arms, water-cooled cables and copper shoes
• Inlet water temperature ≤32℃, outlet water temperature ≤45℃, with interlock alarms for flow rate, pressure and temperature

2.5 Automatic Control System

1. Automatic smelting curve operation (power auto-adjustment for arc striking, melting, reduction, refining and tapping stages)
2. Real-time recording and accumulation of DC voltage, current, power and power consumption
3. Interlock protection and fault alarm storage for water cooling, hydraulic system, tilting and electrode lifting
4. Storage of process parameters, export of historical curves and output statistics

2.6 Auxiliary Supporting Systems

1. Raw Material Batching System: silos, belt conveyors, electronic batching scales (precision ±0.5%), mixing machines
2. Flue Gas Dust Removal System: water-cooled flue + baghouse dust collector, dust removal efficiency ≥99.5%
3. Casting, cooling, crushing, screening and slag recycling systems

3. Main Standard Technical Parameters by Furnace Model

3.1 Core Power Supply & Rectification Parameters

3.2 Mechanical Furnace Body Parameters

3.3 Operational Smelting Parameters (FeV40 Production)

1. Temperature Range

• Melting & Heating Stage: 1600~1700℃
• Main Reduction Reaction Stage: 1800~2100℃ (Aluminothermic/Silicothermic reduction of V₂O₅)
• Refining & Desiliconization Stage: 1650~1850℃

2. Single Heat Smelting Cycle
   
   
   Total duration: 70~90 min per heat; reduction stage 40~55 min, refining stage 10~20 min
3. Power Consumption Index
   
   
   Comprehensive smelting power consumption: 1200~1300 kWh/t FeV40; 5%~8% power saving vs AC furnaces
4. Material Control

• Slag basicity control: 1.3~1.7 (adjusted by lime)
• V₂O₅ content in waste lean slag ≤0.35%; overall vanadium recovery rate 97%~98%

5. Electrode Consumption
   
   
   Graphite electrode consumption of DC furnace: 0.8~1.1kg/t ferrovanadium; traditional three-phase AC furnace: 1.6~2.0kg/t, nearly 50% reduction

4. Core Technical Advantages of DC Ferrovanadium Furnace

1. Concentrated Arc Heat: Single-electrode DC arc radiates vertically downwards to molten pool, lowering thermal load on furnace wall slag line; service life of magnesia lining increased by over 30% with less frequent furnace patching.
2. Grid-friendly Performance: Balanced three-phase current without negative sequence harmonics, requiring smaller capacity reactive power compensation and higher transformer utilization rate.
3. Lower Production Cost: Halved electrode consumption, reduced power consumption per ton product and decreased refractory maintenance cost.
4. Stable Smelting Quality: Uniform electromagnetic stirring in molten pool for even vanadium distribution and minor fluctuation of ferrovanadium chemical composition.
5. Improved Operating Environment: Low noise under submerged arc, less flue gas overflow and slight equipment vibration.