To reduce the environmental pollution caused by graphite dust and waste electrodes, a comprehensive approach is required, encompassing source control, process management, end-of-pipe treatment, and resource utilization. The following are specific measures and implementation points:
I. Graphite Dust Pollution Control
Source Dust Reduction Technologies
- Enclosed Production: Fully enclose graphite processing equipment (e.g., crushers, mills, and screeners) to minimize dust leakage.
- Wet Process Substitution: Adopt wet processing methods during crushing and grinding, using water mist to suppress dust dispersion while lowering operating temperatures and reducing graphite oxidation.
- Low-Dust Raw Material Selection: Prioritize graphite raw materials with uniform particle size and low dust content to minimize secondary dust generation during processing.
In-Process Dust Collection Systems
- High-Efficiency Dust Collectors: Install bag filters, electrostatic precipitators, or cyclone separators for multi-stage purification of dust-laden gases, ensuring emissions meet national environmental standards (e.g., ≤10 mg/m³).
- Localized Exhaust Design: Install local exhaust hoods at dust generation points (e.g., feeding and discharge ports) and integrate them with negative pressure systems for timely dust collection.
- Smart Monitoring: Use dust concentration sensors for real-time emission monitoring, enabling automatic airflow adjustment in dust collection equipment to enhance treatment efficiency.
Dust Recovery and Utilization
- Recycling for Reuse: Screen and purify graphite dust collected by dust collection systems for reuse in electrode production or as additives (e.g., lubricants, conductive materials).
- Co-Disposal: Mix dust that cannot be directly recycled with other industrial wastes (e.g., coal gangue, tailings) to produce building materials (e.g., bricks, road base materials).
II. Waste Electrode Pollution Control
Extending Electrode Service Life
- Optimized Design: Improve electrode structure (e.g., porosity, conductive pathways) through numerical simulations to enhance thermal shock resistance and oxidation resistance.
- Surface Treatment: Apply impregnation or coating technologies (e.g., asphalt impregnation, silicon carbide coating) to improve surface wear and corrosion resistance.
- Smart Monitoring: Embed temperature and stress sensors within electrodes for real-time condition monitoring, preventing overload or localized overheating-induced fractures.
Waste Electrode Classification and Recycling
- Harmless Disassembly: Mechanically crush waste electrodes and separate metallic connectors (e.g., copper nuts) from graphite fragments using magnetic and pneumatic separation.
- Tiered Utilization:
- High-Purity Graphite: Purify through high-temperature treatment (≥2,500°C) for use in premium electrodes or semiconductor materials.
- Medium- to Low-Purity Graphite: Crush for use as a recarburizer in steelmaking or blend with resins to produce graphite products (e.g., seals, molds).
- Residual Waste: Mix with clay to produce refractory bricks or use as road base filler.
Resource Regeneration Technologies
- Chemical Purification: Dissolve impurities (e.g., silicon, iron) in waste electrodes using acid-base solutions, followed by filtration and drying to obtain high-purity graphite powder.
- High-Temperature Graphitization: Heat-treat electrode fragments under inert gas protection (2,000–3,000°C) to restore graphite crystal structure and improve conductivity.
- 3D Printing: Combine waste electrode powder with binders and use 3D printing to fabricate custom graphite components, reducing material waste.
III. Comprehensive Management Measures
- Cleaner Production Audits: Conduct regular assessments to identify high-pollution processes and develop improvement plans (e.g., replacing high-dust equipment, optimizing workflows).
- Regulatory Compliance: Strictly adhere to the Integrated Emission Standard of Air Pollutants (GB 16297) and the Solid Waste Pollution Environment Prevention and Control Law to ensure proper disposal of dust and waste electrodes.
- Circular Economy Model: Collaborate with upstream and downstream enterprises to establish a graphite recycling network, forming a closed-loop “production-use-recovery-remanufacturing”产业链 (industry chain).
- Employee Training and Protection: Strengthen environmental awareness training for operators and provide personal protective equipment (e.g., dust masks, goggles) to mitigate occupational health risks.
IV. Case Studies
- Toray Industries (Japan): Implemented wet grinding and closed-loop water systems to reduce graphite processing dust emissions to below 0.5 mg/m³.
- Fangda Carbon (China): Constructed a high-temperature graphitization line for waste electrodes, recycling 12,000 tons of regenerated graphite electrodes annually and reducing CO₂ emissions by approximately 80,000 tons.
- SGL Carbon (Germany): Developed laser cleaning technology to replace chemical etching, achieving pollution-free electrode surface treatment and reducing wastewater generation by 90%.
By upgrading technologies, optimizing management, and promoting resource utilization, the environmental impact of graphite dust and waste electrodes can be significantly reduced while creating economic value and driving industrial green transformation.
Post time: Aug-15-2025