DC Furnace for Vanadium Iron Slag Treatment

I. Core Principle

• Heat Source Mechanism: Adopting DC arc discharge, a stable, directional and high-energy-density plasma arc column is formed between the graphite electrode (cathode) and the furnace bottom anode, with a temperature reaching 1500–1700℃, featuring concentrated energy and high thermal efficiency.
• Treatment Process:
  1. Vanadium iron slag is completely melted at high temperature, with reductant (carbonaceous material) and flux (lime) added to achieve deep reduction of vanadium and iron oxides.
  2. The reduced vanadium-iron alloy sinks to the furnace bottom due to high density, while vanadium-rich slag / titanium slag floats on the upper layer, realizing efficient separation of slag and iron.
  3. The recovery rate of valuable metals (vanadium, iron) is high, and the tailings can be further used for vanadium extraction or as building materials for resource utilization.
  
  

II. Equipment Structure (Typical Configuration)

• Furnace Body: Refractory lining of magnesia-carbon / alumina-magnesia material resistant to high temperature and erosion, equipped with water cooling system and intelligent temperature control.
• Electrode System: DC graphite electrodes (hollow / solid), adjustable up and down to ensure stable arc and low loss; the furnace bottom is used as conductive anode.
• Power Supply System: Rectifier transformer + DC power supply to provide stable DC current, with a high power factor (up to 0.95–0.98).
• Feeding / Tapping / Deslagging: Continuous / semi-continuous feeding; alloy and molten slag are discharged intermittently through special tapping hole and deslagging hole respectively.
• Flue Gas Purification: Secondary combustion of high-temperature flue gas (mainly CO) + waste heat recovery + dust removal and desulfurization to meet emission standards and recover energy.

III. Process Flow (Vanadium Iron Slag Treatment)

1. Pretreatment: Vanadium iron slag + reductant (anthracite / coke) + flux (lime) → mixing → agglomeration (pellets / blocks).
2. Feeding: Quantitative feeding into the DC furnace.
3. Reduction Smelting: At a high temperature of 1500–1700℃, vanadium and iron oxides are reduced to metals by carbon to form vanadium-iron alloy; impurities such as titanium enter the slag phase.
4. Slag-Iron Separation: Alloy sinks to the bottom and molten slag floats up, with iron tapping and deslagging conducted separately.
5. Product Treatment:
   • Vanadium-iron alloy: Cooled and crushed for sale as metallurgical raw material.
   • Vanadium-rich slag: Further used to extract vanadium pentoxide (V₂O₅); or utilized as cement admixture, road base material, etc.
   
   
6. Flue Gas Treatment: CO combustion for waste heat recovery, flue gas purified to meet emission standards.

IV. Technical Advantages (vs. Traditional Processes)

V. Typical Applications and Cases

• Core Applications: Reduction, vanadium extraction, iron extraction and resource utilization of vanadium-iron alloy smelting slag, vanadium-titanium magnetite smelting slag and low-grade vanadium slag.
• Representative Cases: 3000KVA / 1500KVA DC furnaces for vanadium iron slag treatment customized by industrial furnace manufacturers, which have been put into production and operation, realizing efficient resource utilization of vanadium iron slag with qualified vanadium and iron recovery rates.
• Recycled Products: Vanadium-iron alloy, vanadium pentoxide, cement admixture, road base material, glass-ceramics, etc.

VI. Key Parameters (For Reference)

• Operating temperature: 1500–1700℃
• Furnace capacity: Commonly 1000–5000KVA (e.g. 3000KVA)
• Processing capacity: 30–50 tons of vanadium iron slag per day for 3000KVA model
• Electrode: Graphite electrode (φ300–600mm)
• Operating voltage: 100–300V
• Power factor: 0.95–0.98
• Vanadium recovery rate: ≥85%; Iron recovery rate: ≥98%

VII. Summary