A comprehensive overview of aluminium sorting equipment used in modern recycling facilities, covering technologies from basic separation to advanced alloy sorting systems.
Pre-Sorting & Size Reduction Equipment
Before specific aluminium sorting, material must be properly prepared through these initial processing stages:
- Shredders: Reduce the size of scrap materials (such as cars, siding, and window frames) for easier handling and sorting
- Shears & Balers: Process larger, lighter aluminium scrap like Used Beverage Cans (UBCs) into dense bales for efficient transport and processing
- Trommel Screens: Rotating drums that separate materials by size, removing dirt and small contaminants
Key Sorting Technologies for Separating Aluminium
Advanced technologies for separating aluminium from mixed material streams:
| Technology |
Principle |
Best For |
Pros |
Cons |
| Eddy Current Separators |
Uses a magnetic rotor spinning at high speed to induce an opposing magnetic field in non-ferrous metals (like Al, Cu), repelling them from the main belt |
The workhorse of aluminium recovery - separating non-ferrous metals from inert materials in MSW or shredded auto scrap |
Excellent recovery rates, non-contact, handles high volume, relatively low operating cost |
Cannot separate different non-ferrous metals from each other; less effective on very small or large/flat pieces |
| Sensor-Based Sorters (NIR, Color) |
Uses Near-Infrared (NIR) sensors to identify material type based on spectral signature or color cameras to sort by visual characteristics |
Purity enhancement - can separate aluminium from other metals or contaminants |
High precision, can sort by material and color, software-driven for flexibility |
Higher capital cost, requires pre-shredding and screening for optimal performance |
| Density Separators (Air Classifiers) |
Uses controlled upward airflow to separate light materials from heavier ones |
Pre-sorting before eddy currents - often used for light-lifting shredded aluminium from fluff |
Simple, effective for bulk separation, low cost |
Not precise for final sorting; used as a preparation step |
Advanced Technologies for Alloy Sorting
High-value processes for separating different aluminium alloys (such as 6061 from 3003), which is critical for producing high-quality wrought aluminium alloys.
- Laser-Induced Breakdown Spectroscopy (LIBS): The gold standard for alloy sorting. A high-powered laser ablates a tiny spot on the metal piece, creating a plasma that is analyzed to determine exact elemental composition. Essential for aerospace and automotive alloy remelting applications.
- X-Ray Fluorescence (XRF): Emits X-rays that excite atoms in the metal, which then emit secondary X-rays characteristic of each element. More common for larger pieces or hand-held units for quality control.
System Integration: Typical Aluminium Scrap Processing Flow
Modern recycling plants integrate multiple equipment types into efficient processing lines:
- Shredding: Scrap is shredded into small, uniform pieces
- Screening: Removes fine dust and undersized material
- Magnetic Separation: Removes ferrous metals using powerful magnets
- Eddy Current Separator: Ejects all non-ferrous metals into a separate stream
- Sensor Sorter (NIR/Color): Further cleans the aluminium stream by removing remaining contaminants
- Alloy Sorter (LIBS/XRF): The aluminium stream is fed into advanced sorters that separate pieces by alloy type into different bins
Industry Trends & Innovations
- Artificial Intelligence & Deep Learning: Modern sensor sorters use AI to improve recognition accuracy over time
- Robotic Sorting: Robots with vision systems pick specific aluminium items from conveyors
- Hyper-spectral Imaging: Uses wider spectrum of light for more precise material identification
- Increased Use of LIBS: As demand for high-recycled-content aluminium grows, LIBS systems are becoming more cost-effective
Key Equipment Suppliers
Representative list of leading aluminium sorting equipment manufacturers
Tomra (Norway) - Leader in sensor-based and laser sorting technologies
STEINERT (Germany) - Major provider of magnetic, eddy current, and sensor-sorting solutions
Bühler Group (Switzerland) - Advanced optical sorting solutions
Eriez (USA) - Specializes in magnetic and eddy current separators
MSS, Inc. (USA) - Specializes in optical sorters and AI-powered systems
CP Manufacturing (USA) - Provides integrated recycling systems
Summary
Aluminium recycling begins with eddy current separators for bulk recovery and advances to sensor-based and LIBS technology for creating high-purity, alloy-specific streams that maximize both recycling rates and economic value.
