ASR Plastics Washing & Recycling Line

Applications

The ASR Plastics Washing & Recycling Line targets plastic waste streams contaminated with metal, glass, rubber, and organic material from scrap and recycling operations.

• Automotive Shredder Residue (ASR) Plastic Recovery: reclaims polypropylene, ABS, PVC, and mixed polymer fragments from ELV shredder tailings
• Scrap Metal Industry Plastic Cleaning: processes the plastic byproduct fraction from ferrous and non-ferrous metal recycling yards
• Waste Electrical and Electronic Equipment (WEEE) Plastic Reclamation: separates and cleans housing plastics from shredded e-waste
• Cable and Wire Recycling Plastic Byproduct: cleans the insulation and jacket plastic fraction after copper recovery
• Mixed Polymer Downcycling: prepares contaminated mixed plastic for extrusion into secondary applications (pallets, boards, drainage components)
• Post-Industrial Contaminated Plastic: reclaims plastic from manufacturing scrap contaminated with metal or fluids
• Municipal Solid Waste (MSW) Bottom Ash Plastic: recovers plastic fragments from incinerator bottom ash residue

Theory and Method

Post-shredder plastic waste is heterogeneous by design: it contains multiple polymer types, mixed with metal fragments, mineral fillers, rubber, foam, and adhered organic material. No single separation method can produce clean plastic flakes from this feed, so the line applies mechanical, magnetic, sensor-based, and density-based methods in sequence.

Metal contamination is removed first. A permanent overband magnet extracts ferrous fragments, an eddy current separator throws off non-ferrous conductive particles (aluminum, copper, brass), and an induction metal sorter catches the finest metal fragments. Removing metal before the water bath protects downstream cutting knives, extends pump life, and prevents cross-contamination of the plastic output.

The size-reduced material then enters the wet separation stages. Sink-float separation exploits density differences: a freshwater tank first lets polymers with density less than 1.0 g/cm³ (PP, PE, PS foam) float and skims them off the surface, while heavier particles sink. A second brine tank at controlled specific gravity splits the remaining fraction again to isolate the target plastic from heavier contaminants (dense polymers, mineral filler, residual metal, glass fiber, rubber). A high-speed friction washer then scrubs the flake surface against a rotating rotor and shear ribs, dislodging adhered glue, oil, and dirt. The washed flakes are dewatered in a centrifugal dryer at high G-forces and finished in a vibration dryer that removes residual surface moisture, producing dry, flowable, sortable flake ready for baling or extrusion.

Key Features

The line integrates metal removal, sink-float separation, friction washing, and drying under a single PLC control system.

Permanent Overband Magnet (Self-Cleaning)

The self-cleaning permanent overband magnet suspends above the infeed conveyor and removes ferrous metals before the plastic reaches the shredder. Rare-earth NdFeB magnets deliver strong, stable field intensity without coil power or cooling, and a dedicated self-cleaning belt discharges captured iron continuously.

• Function: pre-shredder ferrous removal to protect cutting knives
• Magnet type: high-performance NdFeB (rare earth), no external excitation power required
• Structure: double-pole magnetic circuit, waist drum-shaped frame with automatic belt tracking

Permanent Overband Magnet Specifications:

Single-Shaft Shredder

The single-shaft shredder performs secondary size reduction to the target flake dimension. A single rotor carries interchangeable knives that shear the material against a stationary comb, and output size is controlled by a bottom screen with user-defined aperture. The machine delivers uniform particle geometry required for downstream eddy current separation and X-ray sorting.

• Function: secondary size reduction to target flake size
• Design: single-shaft rotor with interchangeable knives and screen-controlled output
• Advantage: uniform particle size for sensor-based sorting

Single-Shaft Shredder Specifications:

Concentric Eddy Current Separator

The concentric eddy current separator recovers residual non-ferrous metal fragments (aluminum, copper, brass) from the shredded plastic feed before it enters the water bath. A concentric magnetic rotor design generates a high-frequency alternating field that produces Lorentz repulsion on conductive particles while non-conductive plastic falls straight down. The concentric design is optimized for coarser, mid-fraction material typical of shredder residue plastic.

• Rotor type: concentric high-speed magnetic rotor
• Particle size range: ≥25 mm² (coarse to mid-fraction)
• Function: non-ferrous metal removal from plastic stream
• Feed length: 1500 mm across all models

Concentric Eddy Current Separator Specifications:

Induction Metal Sorter (Sensor-Based)

The induction metal sorter catches conductive fragments too small for the eddy current separator to throw. High-sensitivity electromagnetic sensors identify each metal particle on the conveyor and eject it through compressed-air valves before the plastic enters the water bath.

• Sensor: high-sensitivity electromagnetic (EM) with image-processing algorithm
• Detectable metal size: 1 to 2 mm minimum
• Resolution options: 25 mm or 12.5 mm scan resolution
• Valve options: 48 to 240 valves (belt width dependent)

Freshwater Pre-Washing Tank

The freshwater pre-washing tank uses gravity separation to remove the lightest contaminants from the shredded plastic. Materials less dense than water (PP, PE, foam, some films) float to the surface and are skimmed to a dedicated collection point, while target plastic and heavier contaminants sink and continue downstream.

• Function: floating-fraction removal (PP, PE, foam skim)
• Medium: freshwater at controlled level and flow
• Discharge: overflow skimmer for floatables, submerged conveyor for sinkers

Brine Density Separation Tank

The brine density separation tank uses a controlled-specific-gravity salt solution to make a second density split. The brine density is tuned to the target polymer, so target flakes float while denser contaminants (dense polymers, mineral filler, residual metal fragments, rubber, glass fiber) sink to the bottom and are removed by a submerged screw or scraper.

• Function: heavy-contaminant removal by controlled-density brine
• Sinkers removed: residual metal, rubber, glass fiber, mineral-filled composites
• Brine concentration: adjustable to match target polymer density

High-Speed Friction Washer

The high-speed friction washer scrubs plastic flakes against a rotating rotor and shear ribs to dislodge adhered glue, oil, and organic soil. Water is introduced continuously and drains out through a screen, carrying the removed contamination to the wastewater system. This is the most aggressive washing stage in the line.

• Function: mechanical surface cleaning by shear and friction
• Rotor: high-speed (typically 1,000 to 1,500 rpm)
• Wetting: continuous water spray, screen drainage
• Product contact: stainless steel surfaces

Centrifugal Dryer

The centrifugal dryer removes the bulk of the water from the flakes by high-G spinning. A vertical rotor throws the flakes against a perforated cage, and water is driven off through the perforations while the dried flakes exit at the top. Target output moisture is typically 2% or less.

• Function: high-G mechanical dewatering
• Rotor speed: typically 1,500 to 2,500 rpm
• Output moisture: approximately 2%
• Product contact: stainless steel

Vibration Dryer

The vibration dryer is the final finishing stage. A vibratory screen deck removes residual surface moisture beads and any fines, delivering dry, flowable, and clean flakes to the packaging or downstream extrusion stage.

• Function: final surface-moisture removal and fines classification
• Design: vibratory screen deck
• Output: dry, flowable flakes ready for baling or extrusion

Optical Color Sorter (AI-Powered)

The AI-powered optical color sorter provides a final upgrade of the washed flakes by color. High-resolution cameras and machine-learning classifiers separate clear from colored flakes, remove residual off-color contamination, and can be configured to produce color-specific fractions for higher-value downstream markets.

• Function: color-based flake sorting and contaminant removal
• Detection: high-resolution RGB cameras with AI classification
• Typical application: clear/colored PET flake separation, residual contamination ejection

Chain Apron and Belt Conveyors

Heavy-duty chain apron conveyors handle the highest-abrasion transfers (raw input, pre-shredder feed), while belt conveyors carry clean shredded and washed material between the lighter-duty stages. All conveyors are integrated into the central control system for coordinated line operation.

• Chain apron function: high-abrasion inter-stage transfer
• Belt conveyor function: light-duty transfer between clean stages
• Integration: full PLC coordination and interlock

Electrical Control System

The line runs under a single PLC control system with automatic overload reverse control, interlock logic, and an operator HMI. Motors, water pumps, brine density controls, and pneumatic actuators are wired to the central cabinet for coordinated operation and remote diagnostics.

• Controller: PLC-based programmable control
• Protection: automatic overload reverse, safety interlocks across the full line
• Interface: HMI touchscreen with process-status visualization

Technical Specifications

This line up is engineered around the customer's input composition, throughput target, and target output purity. Water and brine consumption depend on the specific contamination profile of the input material.

Each line up is engineered to the customer's specific plastic waste stream and output requirements. Contact the Torontech application engineering team for a site-specific process flow diagram and quotation.