Which magnetic separators recycling plants use, where each one goes in the line, and how to get more value from the metal you recover.
Short answer: Recycling plants maximize metal recovery by combining magnetic separators and eddy current separators throughout the process. Overband magnets, drum magnets, eddy current separators, stainless steel separators, and magnetic head pulleys each perform a different role in recovering valuable metals and improving product purity.
The answer is rarely a single machine. Whether processing municipal solid waste (MSW), construction and demolition waste, commercial and industrial waste, auto shredder residue, electronic scrap, wood waste, RDF, or SRF, the objective is the same: recover as much valuable metal as possible while producing cleaner recycled commodities.
Most recycling operators achieve the highest recovery rates by combining magnetic separation equipment with eddy current separation technology at multiple stages of the process.
Why does metal separation matter in recycling?
Metal recovery is one of the most important value-generating stages in many recycling operations. Ferrous metals, non-ferrous metals, and stainless steel all have commodity value, while metal contamination can reduce product quality and damage processing equipment.
Effective separation systems help recycling plants:
- Increase revenue from recovered metals
- Improve product purity
- Reduce landfill volumes
- Protect shredders, crushers, and screens
- Lower maintenance costs
- Improve downstream sorting efficiency
- Increase plant throughput
Different metals require different separation technologies. Large steel objects, aluminium cans, copper wire, and stainless steel fragments all behave differently in a recycling process.
Which separators are most common in recycling plants?
Each technology targets a different metal fraction and is typically installed at a specific point in the recycling process:
- Overband magnets
- Primary ferrous recovery from conveyed material.
- Drum magnets
- Continuous ferrous separation from bulk material streams.
- Eddy current separators
- Non-ferrous metal recovery: aluminium, copper, brass, and zinc.
- Stainless steel separators
- Recovery of weakly magnetic stainless steel.
- Magnetic head pulleys
- Ferrous clean-up at the conveyor discharge.
What do overband magnets do in a recycling plant?
An overband magnet is a magnetic separator suspended above a conveyor to remove tramp ferrous metal from conveyed material. In recycling applications, overband magnets are commonly positioned after shredders, screens, bag splitters, or primary conveyors to recover large ferrous contaminants and protect downstream equipment.
Typical recovered materials include steel plate, rebar, structural steel, wire bundles, machine components, steel containers, and large ferrous scrap.
Electro overband magnets
Generate a deep magnetic field and are commonly used on wider conveyors, deeper burdens, and high-capacity recycling lines. For demanding recycling applications, many operators select the ElectroMax overband magnet for its ability to recover large ferrous contaminants from deep material streams.
Permanent overband magnets
Use permanent magnetic blocks to generate the magnetic field and need no electrical power for magnetic performance. They are frequently used on mobile recycling equipment and where simplicity and low maintenance are priorities.
Where do drum magnets fit?
A drum magnet provides continuous and automatic ferrous metal separation from bulk material streams. After primary metal removal, drum magnets recover steel fragments and smaller ferrous particles that remain in shredded material.
Drum magnets are commonly installed after shredders, after screening systems, before density separation equipment, ahead of optical sorters, and before eddy current separators. Because separation is continuous, they are particularly effective in high-throughput recycling facilities processing large volumes of material.
How do eddy current separators recover non-ferrous metal?
Once ferrous metals have been removed, recycling plants typically use eddy current separators to recover valuable non-ferrous metals such as aluminium, copper, brass, and zinc.
An eddy current separator uses a rapidly rotating magnetic rotor to induce electrical currents within conductive metals. These currents create a repelling force that ejects non-ferrous metals away from the material stream, creating a separation.
Eddy current separators are widely used in materials recovery facilities (MRFs), municipal solid waste recycling, construction and demolition waste recycling, automotive shredding, electronic waste recycling, plastics recycling, and incinerator bottom ash processing.
Often the biggest earner. For many recycling plants, the eddy current separator is one of the most important revenue-generating pieces of equipment because it recovers high-value non-ferrous metals that would otherwise be lost.
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Can recycling plants recover stainless steel?
After ferrous and non-ferrous recovery stages, some recycling streams still contain stainless steel. Although stainless steel is often considered non-magnetic, many grades have weak magnetic properties that allow recovery with specialist stainless steel separation technology.
Stainless steel separators are commonly installed after eddy current separators to recover weakly magnetic stainless steel from residual streams such as automotive shredder residue, electronic waste, incinerator bottom ash, metal-rich waste, and mixed scrap. Recovering stainless steel improves overall metal recovery rates and increases the value of recovered commodities.
When are magnetic head pulleys used?
A magnetic head pulley replaces a standard conveyor head pulley and provides an additional ferrous recovery stage at the conveyor discharge point. As material leaves the belt, ferrous metals stay attached to the magnetic pulley while non-magnetic material follows its normal trajectory.
Magnetic head pulleys are typically used as a secondary clean-up stage rather than the primary recovery system. They are particularly useful where space is limited, additional ferrous clean-up is required, product purity specifications are demanding, or a final magnetic separation stage is needed.
What does a typical metal recovery layout look like?
Incoming material conveyor
Overband magnet
Primary ferrous recovery and equipment protection.
Post-shredder processing
Drum magnet
Continuous ferrous metal recovery.
Non-ferrous recovery stage
Eddy current separator
Recovers aluminium, copper, brass, and other conductive metals.
Residual metal recovery
Stainless steel separator
Recovers weakly magnetic stainless steel.
Final clean-up stage
Magnetic head pulley
Secondary ferrous clean-up.
Illustrative layout only. Your line may need more or fewer stages depending on the waste stream.
How do the separators compare?
| Separator type | Primary recovery target | Typical location |
|---|---|---|
| Overband magnet | Ferrous metals | Conveyor transfer points |
| Drum magnet | Ferrous metals | Post-shredder processing |
| Eddy current separator | Aluminium, copper, brass | After ferrous recovery |
| Stainless steel separator | Weakly magnetic stainless steel | After eddy current separation |
| Magnetic head pulley | Residual ferrous metals | Conveyor discharge |
Not sure which combination fits your waste stream? Request a quote, or test your material with Bunting before you buy.
How are metal caps and lids removed in glass recycling?
Glass collected for recycling often arrives with metal caps, lids, and closures still attached or mixed in. Glass makers set limits on how much metal the recycled glass (cullet) can contain, so processors remove it before the cullet is sold.
Steel caps and lids are ferrous, so they are typically removed with an overband magnet above the conveyor or a drum magnet, usually after the glass has been crushed so that closures come away from the bottles. Aluminium caps and rings are non-ferrous and need an eddy current separator. Most glass lines use both, with the magnet ahead of the eddy current separator.
How can recycling plants get more value from recovered metal?
The value of recovered metal depends on its purity as well as its quantity. A ferrous or non-ferrous fraction that carries plastic, paper, glass, or other metals usually sells at a lower grade than a clean one.
Common ways to improve the grade include:
- Adding a second ferrous stage, such as a drum magnet or magnetic head pulley, to clean the fraction recovered by the overband magnet
- Screening material into size fractions before the eddy current separator, so each fraction can be separated at suitable settings
- Adding a stainless steel separator to recover stainless steel that would otherwise be lost to the residue
- Testing your material to confirm the recovery and purity a separator can achieve before choosing equipment
Testing on your own waste stream is the most reliable way to see what recovery and purity are achievable. Find out about material testing.
How do recycling plants select the right separator?
The correct separator depends on the material stream, metal content, throughput, particle size, and recovery objective. Key selection factors include:
- Material type and metal composition
- Particle size distribution
- Conveyor width and burden depth
- Throughput rate
- Required product purity
- Available installation space
- Maintenance requirements
Most successful recycling plants use multiple separation technologies working together rather than relying on a single separator. Overband and drum magnets recover ferrous metals, eddy current separators recover non-ferrous metals, stainless steel separators target weakly magnetic grades, and magnetic head pulleys provide additional clean-up where required. Material testing and application assessment help identify the most effective combination for your plant layout.
Frequently asked questions
Which magnetic separators do recycling plants use to maximize metal recovery?
Recycling plants typically use a combination of overband magnets, drum magnets, eddy current separators, stainless steel separators, and magnetic head pulleys. Each technology targets a different metal fraction, helping operators recover ferrous metals, non-ferrous metals, and stainless steel while improving product purity and reducing waste.
Why are overband magnets used in recycling plants?
Overband magnets are installed above conveyors to remove ferrous metals from conveyed material. They help recover valuable steel and protect shredders, crushers, screens, and other processing equipment from tramp metal damage. Overband magnets are often one of the first metal recovery stages in a recycling process.
What is the difference between a drum magnet and an overband magnet?
An overband magnet removes ferrous metal from a conveyor belt, while a drum magnet continuously separates ferrous metal from a flowing bulk material stream. Overband magnets are commonly used for primary metal recovery and equipment protection, whereas drum magnets are often used for continuous ferrous recovery after shredding or screening.
What does an eddy current separator do?
An eddy current separator recovers non-ferrous metals such as aluminium, copper, brass, and zinc. The separator uses a rapidly rotating magnetic rotor to generate repelling forces that eject conductive metals from the material stream. Eddy current separators are widely used in MRFs, plastics recycling, electronic waste processing, and municipal waste recycling facilities.
Can recycling plants recover stainless steel?
Yes. Although many people consider stainless steel to be non-magnetic, some grades have weak magnetic properties. Specialist stainless steel separators can recover these metals from residual material streams after ferrous and non-ferrous recovery stages, increasing overall metal recovery rates.
Are magnetic head pulleys still used in recycling plants?
Yes, although they are generally used as a secondary ferrous recovery or clean-up stage rather than the primary separator. Magnetic head pulleys are installed at conveyor discharge points and help remove residual ferrous contamination while improving product purity.
Where should magnetic separators be installed in a recycling plant?
The best installation point depends on the process and recovery objective. Overband magnets are commonly positioned above conveyors after shredders or screens, drum magnets are installed within bulk material flows, eddy current separators are located after ferrous recovery stages, and stainless steel separators are typically positioned after non-ferrous recovery systems.
How do recycling plants choose the right magnetic separator?
Separator selection depends on the material being processed, throughput rate, particle size, metal content, conveyor width, burden depth, and required product purity. Most recycling facilities achieve the highest recovery rates by combining multiple separation technologies rather than relying on a single separator.
Which separator recovers the most valuable metals?
The answer depends on the waste stream. Overband magnets and drum magnets recover ferrous metals, while eddy current separators recover high-value non-ferrous metals such as aluminium and copper. In many recycling plants, eddy current separators generate significant revenue because of the value of the recovered non-ferrous metal fraction.
Can magnetic separators improve recycling plant profitability?
Yes. Effective metal separation increases the quantity and quality of recovered metals, reduces equipment damage, lowers maintenance costs, improves product purity, and creates additional revenue streams from recovered commodities. For many recycling operations, metal recovery is a key contributor to overall plant profitability.
