Plastic Sorting Technology: Polymer Identification Capabilities

Modern plastic sorting machines utilize multi-sensor technology to identify and separate 7 major polymer types with 95-99% accuracy, enabling efficient material recovery. This scientific overview examines the technical principles behind polymer differentiation in recycling operations.

Core Polymer Identification Technologies

Near-Infrared (NIR) Spectroscopy

• Principle: Detects molecular bond vibrations

• Identifiable Polymers:

  • PET (Polyethylene terephthalate)

  • HDPE (High-density polyethylene)

  • PP (Polypropylene)

  • PS (Polystyrene)

• Accuracy: 98.5% at 3-8 tons/hour throughput

Laser-Induced Breakdown Spectroscopy (LIBS)

• Function: Elemental analysis of atomic emissions

• Specialized Detection:

  • Black plastics (ABS, PC/ABS)

  • Flame-retardant additives

• Carbon Identification: >99% accuracy

Separable Plastic Types and Properties

Technical Limitations and Solutions

Challenging Materials

• Multi-layer Packaging:

  • Solution: FTIR spectroscopy + delamination

  • Recovery rate: 92%

• Carbon-filled Polymers:

  • Solution: LIBS + AI pattern recognition

  • Identification accuracy: 94%

Contamination Thresholds

Industrial Sorting Configurations

Single-Stream Recycling Line

1. Pre-sorting: Size reduction + film removal

2. Primary separation: NIR polymer identification

3. Secondary sorting:

   • Electrostatic (PVC/PET)

   • Color detection (clear/colored PET)

4. Output: 98% pure polymer streams

Technical Performance Metrics

Emerging Identification Technologies

1. Hyperspectral Imaging

   • 240-band spectral resolution

   • Simultaneous polymer/additive detection

2. Quantum Dot Markers

   • UV-activated fluorescent tagging

   • Sorting accuracy boost: +4.2%

3. Terahertz Spectroscopy

   • Multi-layer material penetration

   • Identification depth: 500μm

Global Recycling Standards

• ISO 15270: Plastics recycling guidelines

• EN 15343: Traceability requirements

• FDA 21 CFR 177: Food-contact compliance

• UL ECOLOGO: Certification for recycled content

Technical specifications based on 2024 industry data from TOMRA, Pellenc ST, and MSS systems. Purity rates represent averages from 35 operational facilities across Europe, Asia, and North America.