Plastic Waste Conditioning via Eddy Current and Air Classification

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Solution Overview

Problem

Existing methods for processing metal-poor plastic waste, such as shredder residues, face challenges in achieving high-quality material separation with reduced wear and tear, particularly in early stages of processing, where non-ferromagnetic metal parts are not efficiently separated for recycling.

Innovation Solution

The method involves separating ferromagnetic components, followed by screening to remove a first and second raw sand fraction, and then using air classification to separate the remaining plastic-rich fraction into light and heavy fractions, with non-ferromagnetic metal parts being separated using eddy current or inductive methods, and heavy material separation via air flow, to reduce wear and enhance recycling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional screening and crushing methods are used to process metal-poor plastic waste, then material separation is achieved, but non-ferromagnetic metal parts are not efficiently separated causing increased wear and reduced recycling efficiency

Engineering Contradiction:
Improveseparation qualityVSAvoidwear
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by introducing eddy current separation and inductive metal separation early in the processing sequence, before the material enters crushing and comminution stages. This preliminary separation of non-ferromagnetic metal parts prevents them from causing wear during subsequent mechanical processing while maintaining high separation quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional mechanical separation methods with eddy current separation and inductive metal separation technologies. These non-mechanical separation methods effectively remove non-ferromagnetic metal parts without the wear associated with mechanical screening and crushing, thereby reducing wear while maintaining separation quality

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If multiple separation stages are implemented to improve material separation quality, then separation precision increases, but process complexity increases

Engineering Contradiction:
Improveseparation precisionVSAvoidprocess complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the separation process into distinct functional stages: ferromagnetic component separation, eddy current separation for non-ferromagnetic metals, inductive metal separation, screening, and crushing. Each stage targets specific material components with specialized separation mechanisms, achieving high separation precision while managing complexity through modular organization

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements multi-functionality by integrating multiple separation technologies (eddy current separation, inductive metal separation, magnetic separation, screening) into a unified processing system. This allows a single integrated plant to handle diverse material types and separation requirements, achieving high separation precision without proportionally increasing overall process complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for the early separation of non-ferromagnetic metal parts, reducing wear and enabling the production of high-quality raw fractions, with the light fraction having a bulk weight <0.2 t/m³ and the heavy fraction >0.3 t/m³, facilitating subsequent recycling processes.

Implementation Method 1

Separating ferromagnetic components from the plastic-rich waste

Methodology Applied
Scientific EffectMagnetic separation: Magnetism

Implementation Method 2

heavy material separation via air flow

Methodology Applied
Scientific EffectAir classification: Density Gradient

Implementation Method 3

non-ferromagnetic metal parts being separated using eddy current or inductive methods

Methodology Applied
Scientific EffectEddy current separation: Eddy Currents

Implementation Method 4

non-ferromagnetic metal parts being separated using eddy current or inductive methods

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2254701B1Method and system for conditioning low-metal plastic waste
Publication Date: 2017.05.10 VOLKSWAGEN AG
  • EP2254701B1 patent drawingFigure 1

AI summary

The invention relates to a method and a system for conditioning low-metal waste rich in plastic, which comprises waste from shredder processes that at least partly contains plastic, particularly from end-of-life vehicles. According to the invention, the method comprises the following steps: - separating ferromagnetic components (FE) from waste rich in plastic, - separating a first raw sand fraction (RS1) from the metal-reduced waste rich in plastic, - comminuting the fraction rich in plastic remaining after the separation of the first raw sand fraction (RS1), - separating a second raw sand fraction (RS2) after the comminution of the remaining fraction rich in plastic, and - separating the remaining fraction rich in plastic into a light fraction (LF) and into a heavy fraction (SF). The system according to the invention comprises the corresponding means for carrying out the individual steps.