Plastic recycling is a critical industrial process that transforms post-consumer and post-industrial waste into reusable materials. As global sustainability demands escalate, understanding the technical workflow and efficiency benchmarks of plastic recycling becomes essential for manufacturers and exporters. Below is a detailed breakdown of the seven-stage industrial recycling process, supported by actionable data.
1. Collection & Pre-Sorting
Recycling begins with systematic collection through municipal programs, industrial scrap recovery, or commercial partnerships. In 2024, global plastic waste collection rates reached 22%, with Europe leading at 42% (Plastics Europe). Pre-sorting removes non-recyclables (e.g., metals, organic matter) to minimize contamination.
2. Automated Sorting & Classification
Advanced facilities deploy AI-powered optical sorters and near-infrared (NIR) spectroscopy to segregate plastics by resin type (PET, HDPE, PVC). A 2025 study by Waste Management World revealed automated systems achieve 98% accuracy, reducing manual labor costs by 40%.
3. High-Pressure Washing & Contaminant Removal
Plastics undergo multi-stage washing with alkaline solutions to eliminate adhesives, labels, and residues. Industrial-scale centrifuges reduce moisture content to <5%, ensuring optimal melting efficiency.
4. Shredding & Size Reduction
Granulators or shredders process cleaned plastics into uniform flakes (5–10 mm). Shredding energy consumption averages 50–100 kWh/ton, depending on resin hardness (PET vs. LDPE).
5. Melt Filtration & Pelletization
Flakes are extruded at 200–300°C, filtered to remove microcontaminants, and pelletized. Modern extruders achieve throughput rates of 1,000 kg/h, with pellet purity exceeding 99.5%.
6. Material Testing & Quality Assurance
Pellets undergo rigorous testing:
- Melt Flow Index (MFI): Ensures consistency in viscosity.
- Tensile Strength: Validates mechanical integrity (e.g., ≥50 MPa for HDPE).
- Contaminant Levels: ICP-MS analysis detects heavy metals (<10 ppm).
7. Compounding & Application-Specific Blending
Additives (UV stabilizers, flame retardants) are integrated to meet end-use specifications. For example, automotive-grade recycled PP requires 15–20% glass fiber reinforcement for structural components.
Comparative Efficiency Table: Mechanical vs. Chemical Recycling
| Parameter | Mechanical Recycling | Chemical Recycling |
|---|---|---|
| Energy Consumption | 8–12 MJ/kg | 20–30 MJ/kg |
| Yield Rate | 85–90% | 70–80% |
| Resin Compatibility | Limited to thermoplastics | All plastics |
| CO2 Reduction | 1.5–2 tons/ton | 2.5–3 tons/ton |