Equipment & Parameter Introduction of Hot Molten Slag Conditioning Furnace

1. Equipment Structure & Working Principle

1.1 Core Structure

• Furnace Body System
  
  
  • Fully Enclosed Furnace Shell: Steel structure shell lined with high-alumina, magnesia-chrome composite refractory materials, resistant to high temperature (above 1600℃) and slag corrosion.
  • Plate-type Water-cooled Furnace Cover: Top sealed structure with built-in cooling water pipes to prevent high-temperature radiation damage and collect flue gas.
  • Working Chamber: Holds molten slag, equipped with electrode holes, feeding ports, slag tapping ports and iron tapping ports (for bottom iron discharge).
  
  
• Heating System (Three-phase AC Electric Arc)
  
  
  • Graphite Electrodes: 3 vertical electrodes generating high-temperature electric arcs to directly heat molten slag.
  • Electrode Lifting System: Hydraulically driven, with PLC automatic control of electrode height to stabilize arc power.
  • Short Network & Water-cooled Cables: Large cross-section, low-impedance design to reduce heat loss and improve power efficiency.
  
  
• Conditioning & Homogenization System
  
  
  • Bottom Nitrogen Stirring: Spray guns installed at the furnace bottom to inject nitrogen and stir the molten pool for uniform composition and temperature.
  • Conditioning Material Feeding Device: Automatically/semi-automatically adds silica, limestone and other auxiliary materials to adjust slag acidity and melting point.
  
  
• Temperature Control & Electrical Control System
  
  
  • Special Transformer: On-load voltage regulation for stable low-voltage and high-current supply.
  • PLC Intelligent Control System: Siemens S7 series, real-time monitoring of current, voltage and temperature, with automatic power adjustment.
  • Infrared Temperature Measurement: Accurate monitoring of slag temperature with control precision of ±5℃.
  
  
• Auxiliary Systems
  
  
  • Water Cooling System: Cools furnace cover, electrodes, cables and slag tapping ports.
  • Flue Gas Dedusting System: Fully enclosed and negative-pressure operation for up-to-standard emission.
  • Hydraulic System: Drives electrode lifting, furnace cover opening and slag gate control.
  
  

1.2 Working Process

1. Slag Receiving: 1200–1300℃ hot molten slag is fed into the furnace via enclosed chutes/slag pots.
2. Heating & Conditioning: Electric arc heating and temperature rise, with conditioning materials added and nitrogen stirring for homogeneity.
3. Homogenization & Heat Preservation: Stable maintenance at 1450–1500℃ to ensure uniform composition, temperature and fluidity of molten slag.
4. Continuous Slag Tapping: Uniformly supplied to centrifuges through flow control devices for drawing into mineral wool.

2. Typical Technical Parameters (Standard 3200KVA Model)

2.1 Core Process Parameters

• Rated Capacity: Approx. 45 tons
• Processing Capacity: 5 tons/hour (continuous slag tapping)
• Annual Processing Capacity: Approx. 30,000 tons
• Raw Slag Temperature: 1200–1300℃
• Tapping Temperature: 1450–1500℃ (stable control)
• Temperature Control Precision: ±5℃
• Conditioning Ratio: Max. 30% (adjustable)

2.2 Electrical Parameters

• Transformer Capacity: HKSSPZ-3200/35 (20% overload allowed)
• Primary Voltage: 35kV
• Secondary Voltage: 170–290V (11-step on-load voltage regulation)
• Phase Number: 3-phase
• Control Mode: PLC automatic constant power / constant current control

2.3 Equipment Specifications

• Furnace Body Diameter: Approx. 5.5–6.5m
• Furnace Body Height: Approx. 4.5–5.5m
• Electrode Diameter: Φ350–450mm (graphite)
• Cooling Water Consumption: Approx. 50–80m³/h
• Total Equipment Weight: Approx. 150–200 tons

3. Main Functions & Advantages

• High Energy Efficiency: Direct utilization of hot molten slag sensible heat, saving over 15% energy compared with cold slag process; waste heat recovery rate >80%.
• Stable Product Quality: Precise temperature control and stirring ensure uniform molten slag and stable mineral wool quality.
• Environmental Protection: Fully enclosed and negative-pressure operation, free of dust and wastewater, solving traditional water quenching pollution.
• Intelligent Automation: Full-process PLC automatic control, reducing manual intervention and ensuring safe operation.
• Solid Waste Recycling: Converts metallurgical waste slag into high-value-added thermal insulation materials with significant economic benefits.

4. Main Application Fields

• Ferroalloy Industry: Production of mineral wool from silicomanganese slag, ferronickel slag, ferrochromium slag.
• Iron and Steel Industry: Resource utilization of blast furnace slag and steel slag.
• Non-ferrous Metallurgy: Treatment of various non-ferrous metal smelting slags.