Metal Removal in Plastic Recycling: Protecting Cleaner Flake Streams
California's February 2026 Current State of Processing report puts contamination at the center of recycling operations. The assessment identified 89 facilities handling covered packaging materials, with approximately 5.9 million tons of incoming covered material and an estimated 2.9 million tons of sorted output after contamination removal and processing losses. Those are statewide processing estimates, not a plastic-only recovery rate or an equipment performance claim.
For plants handling PET bottles, rigid HDPE containers or mixed shredded plastics, the practical question is narrower: how can steel and aluminum contaminants be removed before they damage machinery or compromise a recycled-plastic product?
Where Metal Enters a Plastic-Rich Stream
Collected plastic is not always plastic alone. PET bottle bales may include aluminum caps or rings, while mixed rigid-plastic feed can carry screws, steel fragments, wire and small pieces of foil. Metal may also enter during handling, shredding or transport.
A metal fragment embedded in a plastic item behaves differently from a loose fragment. If both enter a granulator together, the metal may become harder to isolate once the stream contains many small particles. Early inspection and removal of obvious contaminants are therefore important, especially where the next machine has cutting blades or other vulnerable components.
The objective is not to claim that one separator makes a plastic stream ready for extrusion. It is to remove a defined category of contamination before other necessary cleaning and quality-control stages.
Magnetic Separation: Remove Ferrous Contaminants First
A magnetic separator targets iron, conventional steel and other magnetically responsive pieces. It can be installed at an appropriate point in material preparation, where metal is exposed and the feed is distributed consistently.
For plastic recyclers, this stage can remove steel fasteners, clips and fragments before they continue downstream. However, magnetic separation does not recover aluminum caps or copper wire, and it cannot solve non-metallic contamination such as labels, dirt or glass.
Material depth matters. A dense pile of bottles or flakes can conceal small pieces, and ferrous items attached to larger plastic objects may be carried along with those objects. Equipment placement should reflect whether the line handles whole containers, shredded pieces or washed flakes.
Eddy Current Separation: Recover Conductive Non-Ferrous Metal
After ferrous removal, an eddy current separator can help separate exposed aluminum and other conductive non-ferrous pieces from suitable non-conductive plastic-rich material. Its changing magnetic field induces currents in conductive particles, altering their trajectory at discharge.
This is particularly relevant when aluminum caps, rings or fragments remain mixed with plastics. The separator is recovering conductive metal; it is not identifying PET, HDPE or PP by polymer chemistry.
Feed condition determines whether this stage is practical. Small or very thin metal pieces may respond differently from larger rigid fragments. Wet, sticky material, inconsistent particle size and thick feed layers can reduce separation stability.
Metal still attached to plastic can also follow an unpredictable path. A trial using representative material is more useful than assuming a standard configuration will work for every plastic stream.
A Practical Quality-Control Sequence
A workable line begins by defining the incoming plastic type, the metal contaminants present and the required output specification. Size classification may be appropriate when large pieces and fines are mixed, but it should not be added automatically to an already uniform stream.
CurrenTek lists plastic recycling metal removal as an application for its magnetic and eddy current equipment. The process can be configured around ferrous removal followed by conductive non-ferrous recovery, with additional cleaning or quality checks performed as needed.
Operators should sample both the recovered plastic and rejected metal fractions. Useful measures include residual metal contamination, plastic carried into metal rejects, stoppages and changes in quality across shifts.
Better separation has value when it reduces equipment risk and makes the plastic feed more consistent without discarding unnecessary recoverable material.