Good quality blast-furnace slag holding furnace Solid waste residue
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- 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.
- 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).
- 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.
- 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).
- 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.
The blast furnace slag holding furnace has a modular design, focusing on high-temperature resistance, thermal insulation, and easy operation.
- 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.
The core of energy saving is to reduce heat loss and maximize the use of slag’s latent heat.
- 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.
The blast furnace slag holding furnace is not the only storage solution; here’s how it compares to two common alternatives:
