Blast Furnace Slag Holding Furnace For Solid Waste Treatment

Good quality blast-furnace slag holding furnace Solid waste residue

Core Functions

• Heat Preservation & Temperature Stabilization: Maintains molten slag at 1450–1550°C to prevent solidification, avoiding blockages in downstream pipelines or equipment.
• Slag Homogenization: Eliminates composition and temperature differences in slag through gentle stirring, improving the quality of finished products (e.g., slag cement, aggregates).
• Buffer Regulation: Balances the mismatch between blast furnace slag discharge rhythm and downstream processing capacity, ensuring continuous production.
• Pretreatment Assistance: Facilitates impurity floating or component adjustment (e.g., adding modifiers) to optimize slag performance for subsequent utilization.

Key Working Principle

• Adopts indirect heating (e.g., resistance heating, gas combustion) or self-insulation (relying on slag’s own latent heat + high-efficiency insulation layers).
• The furnace body is lined with high-alumina or magnesia-chrome refractory materials to withstand high temperatures and slag erosion.
• Molten slag enters the furnace through a feeding port, stays for 1–4 hours (adjustable by production demand), and is discharged via a bottom tapping hole or overflow port to downstream equipment (e.g., granulators, slag wool production lines).

Typical Application Scenarios

• Slag Granulation System: Supplies stable-temperature molten slag for producing granulated blast furnace slag (GBFS), a key raw material for high-performance concrete.
• Slag Wool Production: Provides continuous, uniform molten slag to manufacture thermal insulation materials like slag wool.
• Slag Casting/Processing: Conditions slag for casting into slag blocks (used as roadbed materials) or further processing into mineral wool boards.
• Emergency Backup: Stores slag temporarily when downstream equipment malfunctions, avoiding blast furnace production interruption due to slag accumulation.

Core Technical Parameters

• Working Temperature: 1450–1550°C (matches blast furnace slag tapping temperature).
• Furnace Capacity: 50–500 tons (industrial-scale; small backup furnaces ≈50–100 tons, large production-line furnaces ≈300–500 tons).
• Heat Loss Control: ≤5–8°C/hour (via composite insulation layers: refractory brick + ceramic fiber + thermal insulation coating).
• Discharge Method: Gravity tapping (bottom or side port) or overflow discharge, with flow control valves for precise regulation.
• Refractory Service Life: 3–5 years (depending on slag erosion intensity and maintenance frequency).

Advantages:

• Guarantees Continuous Production: Resolves the "supply-demand asynchrony" between blast furnace and slag processing, reducing production downtime.
• Improves Slag Utilization Rate: Stable temperature and composition enhance the quality of slag-derived products, increasing resource conversion efficiency.
• Low Energy Consumption: Mostly relies on slag’s self-heat, with auxiliary heating only for temperature compensation, energy-saving compared to re-melting solidified slag.

1. Equipment Structure Details

Key Components

• Furnace Body: Vertical cylindrical structure (height-diameter ratio 1.2–1.5:1) to ensure uniform slag temperature. Lined with three layers:
  • Working layer: High-corrosion-resistance magnesia-chrome brick or alumina-magnesia-carbon brick (thickness 300–400 mm) to withstand slag erosion.
  • Insulation layer: Ceramic fiber blanket + lightweight refractory brick (thickness 200–300 mm) to reduce heat loss.
  • Outer shell: Steel plate (10–15 mm thick) with reinforcement ribs for structural stability.
• Feeding & Discharge System:
  • Feeding port: Located at the top, equipped with a refractory-lined chute and sealing cover to prevent heat loss and dust emission.
  • Discharge device: Bottom/side tapping port with refractory sleeve and flow control valve (pneumatic or hydraulic) for precise slag output adjustment.
• Heating & Temperature Control System:
  • Auxiliary heating: Resistance heating elements (embedded in the furnace wall) or gas burners (installed at the furnace top) for temperature compensation.
  • Temperature monitoring: Multiple thermocouples (installed at different heights) connected to a PLC system for real-time temperature display and automatic heating control.
• Safety Devices:
  • Pressure relief valve: Releases excess gas to avoid overpressure in the furnace.
  • Emergency discharge port: For rapid slag release during equipment failure.
  • Thermal expansion joints: Absorb furnace body deformation caused by high temperatures.

2. Energy-Saving Optimization Measures

• Optimize Thermal Insulation Structure:
  • Adopt composite insulation layers (e.g., ceramic fiber + aerogel insulation material) to reduce heat loss by 15–20% compared to traditional structures.
  • Seal the furnace top and feeding/discharge ports with high-temperature resistant gaskets to prevent hot air leakage.
• Intelligent Temperature Control:
  • Use PID precise control to activate auxiliary heating only when slag temperature drops below 1450°C, avoiding unnecessary energy consumption.
  • Match heating power with slag storage volume (e.g., reduce power when the furnace is half-full) to improve energy efficiency.
• Waste Heat Recovery:
  • Install heat exchangers around the furnace body to recover waste heat and preheat combustion air (for gas-heated furnaces) or boiler feedwater, reducing auxiliary energy consumption by 10–12%.
• Optimize Slag Residence Time:
  • Adjust the holding time based on downstream demand (1–4 hours) to minimize heat loss caused by long-term storage.

3. Comparison with Other Slag Storage Technologies

Slag holding furnace

Solid Waste Treatment holding furnace

Solid waste Blast Furnace

Blast Furnace Slag Holding Furnace For Solid Waste Treatment Images