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Problem guide: aluminum and non-ferrous metal

Recovering aluminum and other non-ferrous metal

Non-ferrous recovery is the job of pulling aluminum, copper and other metals that a magnet will not lift out of a mixed stream, so they can be sold as metal instead of lost to the residue or left as contamination in other products.

By [author name, role and employer] · Technical review by [reviewer name, role and employer] · Updated

  • Aluminum and non-ferrous
  • Ferrous
  • Fiber
  • Glass
  • Film
  • Other and residue

1What it involves

In most plants one machine does most of the work: an eddy current separator. Several things upstream decide whether it can. The separator only acts on what reaches it. If steel is still in the stream, if pieces are stacked on each other, or if the size range is too wide, it will miss metal however it is set.

The work splits into three parts: preparing the stream (removing ferrous metal, screening to a size range, spreading it into one layer), separating it (the eddy current separator and its splitter), and checking the result (what ends up in the metal product, and what metal ends up in the residue).

Across three single-stream MRF studies, an average of 73.4% of cans ended up in the aluminum product; 15.5% left with the fiber and 7.2% with the residue. One of the three studies estimated its figure rather than measuring it. Source: GBB for CMI, Aluminum Beverage Can: Driver of the U.S. Recycling System, 2020 (source 1).

A separator can only recover the cans that reach it, and much of the loss happens before that. GBB reports that most separator vendors guarantee to capture at least 95% of the cans on the container line. Upstream, crushed cans fall through screens, flattened cans ride with the paper, and bagged loads are pulled at presort. Source: GBB for CMI, Aluminum Beverage Can, 2020 (source 1). Where a MRF loses cans, and what each fix recovers: Aluminum recovery on MRF container lines.

The short version

Remove ferrous metal first. Feed one layer. Set the splitter for the purity your metal buyer needs, then measure what you lose.

2Recovery and purity

Two numbers describe how well a separator works, and they pull against each other.

Recovery
The share of the target metal in the feed that ends up in the product.
Purity
The share of the product that is the target metal.

Feed: 10 aluminum pieces among 29

Product: 9 pieces

Residue: 20 pieces

Recovery = aluminum in product ÷ aluminum in feedThe two aluminum pieces in the residue are lost recovery.
Purity = aluminum in product ÷ everything in productThe one glass piece in the product lowers purity.
Figure 2. Recovery and purity, counted in pieces. Counts chosen for easy arithmetic; they are not typical recovery, purity or feed composition. Plants measure both by weight.

The splitter sets the trade. Move it toward the rotor and more weakly thrown metal lands on the product side, so recovery rises; so does the non-metal that drops in with it, so purity falls. Move it away and the reverse happens.

Small moves matter. In plant and lab tests on 1 to 6 mm bottom ash, shifting the splitter by 10 mm can change metal recovery by about 10% and grade, the measure of purity, by about 18%. Source: Rahman and Bakker, Sensor-based control in eddy current separation of incinerator bottom ash, Waste Management, 2013 (source 2).

Which side to favour depends on the purity your metal buyer will accept and what a lost piece of metal is worth to you.

ReMA's grade for baled used beverage cans, Taldon, sets no aluminum percentage. It asks for magnetically separated beverage cans only, free of steel, lead, plastic, glass, wood, dirt and trash. Bales must be at least 14 lb/ft³, and at most 17 lb/ft³ unflattened or 22 lb/ft³ flattened. Source: ReMA, ReMA's ISRI Specifications, July 2026, p. 8 (source 3).

Buyers grade each load when it arrives. Two can-sheet mills' published specs both set a 4% moisture threshold, above which a load can be rejected or docked by weight. Both mills' reject lists name plastic sleeves and tops, foil and pie pans. They differ on aluminum food cans: one accepts clean, dry, label-free ones up to 10% of a bale by volume, and the other treats them as grounds for downgrade or rejection. Sources: Novelis, UBC Product Quality Specification, Rev 7, 2021, sections 2.2, 2.3 and 2.5; Tri-Arrows Aluminum and Logan Aluminum, Used Beverage Cans (UBC) Specification, 2020, sections 8 and 9 (sources 4 and 5). [confirm with each mill that its spec is current before the mills are named on a live page]

The Aluminum Association puts a typical can bale at about 94% metal, and reports that recyclers have seen bales as low as 85% as contamination has grown. Source: Aluminum Association, Four Keys to Circular Recycling: An Aluminum Container Design Guide, 2020, citing a 2018 review (source 6).

Ask your buyer for its written spec before you set the splitter. Grades for shredded scrap, and what each buyer rejects: Aluminum scrap grades and what buyers accept.

3Where the metal comes from

Non-ferrous metal turns up in several kinds of stream, each with different company. The company decides what has to come out first and how narrow the size range must be.

On single-stream lines the metal is a small share of what arrives. Across eight composition studies, cans averaged about 2.2% of inbound weight in states without a container deposit and about 0.4% in deposit states. Source: GBB for CMI, Aluminum Beverage Can, 2020 (source 1).

Streams that carry non-ferrous metal
StreamWhat the metal looks likeWhat travels with it
Single-stream recycling, container lineBeverage cans, foil, traysPlastic containers, glass, some fiber and film
Shredded scrap (auto and appliance)Shredded aluminum, copper, brass and zinc, and insulated wire; the separator's product is sold as ZorbaPlastics, rubber, foam, wood, stones, dirt, glass, circuit boards, some stainless steel
Glass processingCaps, rings and other closures, can pieces. Here the metal is the contaminant: furnace-ready cullet must be free of itCullet, labels and paper, plastic, ceramics, stones
Incinerator bottom ashAbout 1 to 5% of the ash, mostly aluminum; small pieces, often coated after quenchingMineral ash, glass and ceramics, ferrous metal
Construction and demolition (C&D) wasteSmall amounts from wiring, siding, fasteners and flashing; on most large projects, copper and aluminum are recycled on siteSoil, concrete, wood, drywall, ferrous metal

Sources: GBB for CMI, 2020 (1), single-stream; Kelly and Apelian for the Aluminum Association, 2016 (7), and ReMA, 2026 (3), shredded scrap; EU Joint Research Centre, 2011 (8), and ReMA, 2026, glass; Šyc et al., 2020 (9), bottom ash; Florida DEP, about 2000 (10), Musson, Xu and Townsend, 2008 (11), and Terex Recycling Systems (12), C&D.

For C&D, published evidence is thin. In the one plant case found, the separator treats the 10 to 100 mm heavy fraction after screening, magnets, air separation and hand picking, and the 0 to 10 mm fines leave without eddy current treatment. Source: Terex Recycling Systems, First Plant Install, undated (source 12).

Shredded electronics are another source. Magnets and eddy current separators recover the larger ferrous, copper and aluminum pieces at fairly high purity, but much of the metal stays in the fine and dust fractions, where it is harder to recover. Source: Malcharcziková, Skotnicová and Kesavan, Materials 19(6), 2026 (source 13). Sensor-based sorting uses a lot of computing power and compressed air, so it is used mostly on higher-value streams such as electronics. Source: Šyc et al., Metal recovery from incineration bottom ash, 2020 (source 9).

4Technology options

Most aluminum lines combine several technologies. This table compares what each separates by, its role in an aluminum line, and what it needs from the feed.

Technologies in an aluminum line (compared on stated criteria, not ranked)
TechnologySeparates byRole in an aluminum lineNeeds from the feed
Eddy current separationConductivity relative to densityThe main separator for aluminum and other non-ferrous metalOne layer, ferrous removed, a limited size range
Magnetic separationMagnetic attractionRemoves steel upstream to protect the separatorA burden shallow enough for the field to reach
Sensor-based sortingWhat a sensor reads: metal content, X-ray, near-infrared, colourPicks metals an eddy current separator misses, such as stainless steel, or cleans up the metal productPieces spread apart in a thin layer
ScreensSize and shapeSplits the stream into size fractions, so each separator sees a narrow rangeA screen type suited to the material: wet, sticky or wiry feed can blind, plug or wrap some screens
Manual sortingWhat a person seesQuality control on the product. Some plants staff it; others sell the product as it comesA pace people can keep: up to about 50 picks a minute of one material for a skilled sorter

Sources: Goudsmit Magnetics knowledge base (14), eddy current; Bunge, OST, 2019 (15), one layer, magnet reach and screening; IMI service manual (16) and Eriez RM-99, 2015 (17), ferrous first; Šyc et al., 2020 (9), and Kelly and Apelian, 2016 (7), sensor sorting; GBB for CMI, 2020 (1), manual sorting.

Remcon Equipment, the publisher's affiliate, describes the eddy current separator systems it builds on its own site: remconequipment.com/eddy-current-aluminum-separators.

Who publishes this. Recyclers Guide is published by [LLC name], an affiliate of Remcon Equipment, Inc. Remcon designs and builds conveyors and eddy current separator systems around rotors or complete separators made by others, builds overhead magnet units, magnetic head pulleys and trommels, resells screens and feeders, and integrates equipment discussed on this site.

5Designing the line

The separator does the separating; the equipment around it decides what it is given to work with.

On a single-stream container line, screens first split flat fiber from containers. Magnets then pull steel, and the eddy current separator follows the magnets. Source: GBB for CMI, Aluminum Beverage Can, 2020 (source 1). Remcon Equipment, the publisher's affiliate, gives the same order on its sorting and separation page.

Four settings matter most; their letters match the figure. Designing an aluminum recovery line covers the order of machines, and what each needs from the one before it, in more detail.

An eddy current line, side elevation Material rides an inclined infeed conveyor with a magnetic head pulley that drops steel into its own chute. The rest falls onto a vibratory feeder, which spreads it into one layer on a short eddy current separator belt. At the separator head, aluminum is thrown over an adjustable splitter into the product bin and everything else drops into the residue bin. 1 2 3 4 5 6 A B C D The separator end of an eddy current line, side elevation Material that has already passed the infeed conveyor and magnet falls onto a vibratory feeder, which spreads it into one layer on a short eddy current separator belt. At the separator head, aluminum is thrown over an adjustable splitter into the product bin and everything else drops into the residue bin. From the infeed and magnet (1, 2) 3 4 A B C 5 D 6
  1. 1Infeed conveyor. Material arrives in a deep, uneven burden.
  2. 2Magnetic head pulley. Steel stays on the belt around the pulley and drops into its own chute.
  3. 3Vibratory feeder. Spreads surges into an even flow across the belt.
  4. 4Eddy current separator. A short belt with the magnetic rotor inside its head pulley.
  5. 5Residue. Everything that is not thrown.
  6. 6Non-ferrous product. Metal thrown over the splitter.
Figure 3. One common arrangement of an eddy current line, side elevation. Schematic, not to scale. Plants also use overhead magnets, screens and second separators.

Feed presentation

How material is presented decides much of what the separator recovers. A metering device upstream, such as a vibratory feeder, spreads it across the full width, and the faster separator belt thins it to one layer. Sources: IMI service manual (16); Bunting, 5 Key Eddy Current Separator Operating Parameters, 2020 (18). Remcon Equipment, the publisher's affiliate, covers surge control and spreading in its feed-presentation guide, written for optical sorter lines.

Layer depth

Aim for a single layer, about as deep as the largest piece, with no piece lying on another. A can under a piece of cardboard is shielded from the throw and drops with the residue; a non-metal piece lying on a can rides into the product. Deeper burden lowers both recovery and purity. Sources: Goudsmit, EddyFines product page (19); IMI service manual (16). Depth follows from feed rate, belt width, belt speed and bulk density together. The belt feed-rate calculator shows how they relate, and the bulk density reference gives approximate densities to start from.

Belt speed

Belt speed sets layer depth, how long each piece spends in the field and the path it leaves on. Too fast a belt rushes material through the field, and a faster belt does not necessarily separate better. Sources: Bunting, 2020 (18); IMI service manual (16). Machines differ. IMI sets its separator belt with a variable-frequency drive, 384 fpm at 60 Hz. Eriez's REA design runs fixed or variable depending on the options bought. Remcon Equipment, the publisher's affiliate, runs its standard separator at a fixed 200 fpm. Sources: IMI (16); Eriez, SM-780-1, 2010 (20); Remcon Equipment (21). Ask each maker whether belt speed is fixed or adjustable, and over what range.

Splitter position

The splitter is the adjustable edge that divides product from residue. Its position is the main day-to-day control of the recovery and purity trade, and small moves change both (section 2). Plan for an operator to reach it safely and to see where material is landing. Where to start it and how to check it: Setting the splitter on an eddy current separator.

Steel has to come out before the separator

Steel that reaches the rotor is pulled toward it, not thrown. Makers' manuals say trapped steel heats up, can damage the belt and shell, and can permanently weaken the rotor's magnets. No magnet catches every piece, so they advise one or more magnets upstream. Sources: IMI service manual (16); Eriez RM-99, 2015 (17).

Where to put the magnet: Removing ferrous metal before the separator.

[worked example: an anonymised compact container line built by the publisher's affiliate, once Sean approves publishing it and the shop confirms the order of its machines]

6Selecting equipment

Questions that size the machine

  • What is in the stream, and how much of it is the metal you want? A waste characterisation study answers this.
  • What form is the metal in: whole cans, flattened cans, shred, foil, wire?
  • What size range reaches the separator, and is it screened into fractions?
  • What feed rate must the line handle, and how much does it swing during a shift?
  • What is the material's bulk density, and how was it measured?
  • How is ferrous metal removed upstream, and how much gets past it?
  • How wide is the belt the material arrives on, and how much space is there for the separator, chutes and conveyors?
  • What grade will you sell, and what purity does your metal buyer require?
  • Is the material wet, sticky or dusty?

How makers turn these answers into a belt width and a model: Sizing an eddy current separator. Splitting the feed into size fractions: Screening the feed into size fractions before separation. Pieces too small for a conventional separator: Recovering fine non-ferrous metal.

RFQ checklist

Tick items off as you gather them. Nothing here is saved or sent.

Ask each manufacturer the same questions in the same order. Comparing answers is easier than comparing brochures. The full RFQ checklist for a non-ferrous recovery line adds questions for magnets, sensor sorters and your metal buyer.

7Questions

Should I set the splitter for recovery or for purity?

It depends on the purity your metal buyer accepts and what a lost piece of metal costs you. Moving the splitter toward the rotor raises recovery and lowers purity; moving it away does the reverse. Small moves matter, so check both output streams after each change.

What should an RFQ for aluminum recovery include?

A description and photos of the stream, the feed-rate range, the size range, the bulk density and how it was measured, how ferrous metal is removed upstream, your metal buyer's spec and the purity you need, the space available, how conveyors and controls connect, and site conditions.

[question on what separates aluminum cans from other material: held until Sean decides whether this site or the affiliate's site answers it]

8Build an RFQ

Answer what you can; blanks are fine. You choose who receives the inquiry, and the form shows the list before you send.

Not ready for quotes? Ask an engineer at Remcon Equipment, the publisher's affiliate, a question instead.

Lowest to highest, in tons per hour. The belt feed-rate calculator works it out from belt speed and load.

Smallest to largest piece, and any screening upstream

From your buyer's specification, if you have one

Is ferrous metal removed upstream?
Who receives this inquiry

Recyclers Guide is published by [LLC name], an affiliate of Remcon Equipment, Inc. Remcon sells conveyors and separation equipment.

Tick each company you want to hear from; nothing is ticked for you. These are the listings in the directory whose equipment this guide covers, grouped by role. Within each group the order rotates daily. How this list is ordered

Recover non-ferrous directly

Eddy current separators and sensor-based sorters

Upstream in an aluminum line

Magnets and screens

When you send, your answers, name and email go automatically to each company you tick. No one at [LLC name] or Remcon Equipment reads inquiries addressed to other companies. [LLC name] keeps only the date and the recipients, not what you wrote. Remcon Equipment is not a recipient on this form. How this is kept and deleted: [privacy notice].

Who publishes this. Recyclers Guide is published by [LLC name], an affiliate of Remcon Equipment, Inc. Remcon designs and builds conveyors and eddy current separator systems around rotors or complete separators made by others, builds overhead magnet units, magnetic head pulleys and trommels, resells screens and feeders, and integrates equipment discussed on this site.

9Sources

Every number on this page, other than the made-up counts in Figure 2, comes from the sources below, each read on 2026-10-06. Wording is paraphrased. Manufacturer sources are each maker's own published material, cited for what that maker states.

  1. Gershman, Brickner & Bratton (GBB), for the Can Manufacturers Institute (CMI). Aluminum Beverage Can: Driver of the U.S. Recycling System. June 23, 2020. Industry association, commissioned report. https://www.cancentral.com/wp-content/uploads/2023/03/GBB-Report-Aluminum-Can-Drives-U.S.-Recycling-System-Final-2020-0623.pdf. Read 2026-10-06.
  2. Rahman, M.A. and Bakker, M.C. Sensor-based control in eddy current separation of incinerator bottom ash. Waste Management 33(6), 2013. Peer-reviewed; abstract read. https://pubmed.ncbi.nlm.nih.gov/23490354/. Read 2026-10-06.
  3. Recycled Materials Association (ReMA). ReMA's ISRI Specifications. July 2026 (Taldon, p. 8; Zorba, pp. 11 and 17; glass cullet, pp. 28 to 31). Industry trading standard. https://www.isrispecs.org/wp-content/uploads/2026/09/2026-July-ReMA_ISRI_Specifications.pdf. Read 2026-10-06.
  4. Novelis. NNA Recycling: UBC Product Quality Specification, REF-04146, Rev 7. File dated July 14, 2021, posted 2026. Manufacturer (can-sheet mill and UBC buyer). https://novelis.com/wp-content/uploads/2026/05/NNA-UBC-Spec_v7_REF-04146.pdf. Read 2026-10-06.
  5. Tri-Arrows Aluminum and Logan Aluminum. Used Beverage Cans (UBC) Specification. April 28, 2020. Manufacturer (can-sheet mill and UBC buyer). https://www.loganrawmaterials.com/wp-content/uploads/2020/04/UBC-Printable-PDF.pdf. Read 2026-10-06.
  6. Aluminum Association. Four Keys to Circular Recycling: An Aluminum Container Design Guide. September 2020 (p. 6, citing Capuzzi and Timelli, Metals, 2018, which could not be opened). Industry association. https://www.aluminum.org/sites/default/files/2021-10/AA_ContainerDesignGuide.pdf. Read 2026-10-06.
  7. Kelly, S. and Apelian, D. (Worcester Polytechnic Institute), for the Aluminum Association. Automotive Aluminum Recycling at End of Life: A Grave-to-Gate Analysis. 2016. Industry association, commissioned academic study. https://www.aluminum.org/sites/default/files/2021-10/Final-Report-Automotive-Aluminum-Recycling-at-End-of-Life-A-Grave-to-Gate-Analysis.pdf. Read 2026-10-06.
  8. European Commission Joint Research Centre. End-of-Waste Criteria for Glass Cullet: Technical Proposals, EUR 25220 EN. 2011. Government. https://publications.jrc.ec.europa.eu/repository/bitstream/JRC68281/jrc68281.pdf. Read 2026-10-06.
  9. Šyc, M. et al. Metal recovery from incineration bottom ash: state-of-the-art and recent developments. Journal of Hazardous Materials 393, 2020. Peer-reviewed. https://doi.org/10.1016/j.jhazmat.2020.122433 (open-access copy: https://d-nb.info/1206412569/34). Read 2026-10-06.
  10. Florida Department of Environmental Protection. C&D Debris Recycling Study: Final Report. About 2000. Government. https://floridadep.gov/sites/default/files/CDreport5-8.pdf. Read 2026-10-06.
  11. Musson, S.E., Xu, Q. and Townsend, T.G. Measuring the gypsum content of C&D debris fines. Waste Management 28(11), 2008. Peer-reviewed; abstract read. https://pubmed.ncbi.nlm.nih.gov/17980573/. Read 2026-10-06.
  12. Terex Recycling Systems. First Plant Install. Undated. Manufacturer case study. https://www.terex.com/recycling/first-plant-install. Read 2026-10-06.
  13. Malcharcziková, J., Skotnicová, K. and Kesavan, P.K. Materials 19(6), article 1222. 2026. Peer-reviewed. https://pmc.ncbi.nlm.nih.gov/articles/PMC13028589/. Read 2026-10-06.
  14. Goudsmit Magnetics. What determines the separation efficiency of eddy current systems (knowledge base). Undated. Manufacturer. https://www.goudsmitmagnetics.com/en-us/knowledge-base-efficiency-of-eddy-current-separators. Read 2026-10-06.
  15. Bunge, R. Recovery of Metals from Waste Incinerator Bottom Ash. UMTEC, OST Eastern Switzerland University of Applied Sciences, June 2019. Technical monograph. https://www.ost.ch/fileadmin/dateiliste/3_forschung_dienstleistung/institute/umtec/fachartikel/2019/19-03_recovery_of_metals_from_waste_incinerator_bottom_ash.pdf. Read 2026-10-06.
  16. Industrial Magnetics, Inc. (IMI). Eddy Current Separator Service Manual, Endless Belt (900505). Undated. Manufacturer. https://assets.magnetics.com/assets/files/manuals/900505_ECS_Service_Manual_Endless_Belt.pdf. Read 2026-10-06. Industrial Magnetics supplies eddy current separators and magnets to Remcon Equipment, the publisher's affiliate.
  17. Eriez. RevX-E Eddy Current Separator Installation, Operation and Maintenance Manual, RM-99. April 2015. Manufacturer. https://www.eriez.com/Documents/Literature/IOMs/Metals-Recycling/RM-99-Eriez-RevXE-Eddy-Current-Separator-IOM.pdf. Read 2026-10-06.
  18. Bunting. 5 Key Eddy Current Separator Operating Parameters. November 10, 2020. Manufacturer. https://buntingmagnetics.com/blog/5-key-eddy-current-separator-operating-parameters. Read 2026-10-06.
  19. Goudsmit Magnetics. EddyFines eddy current separators (product page). Undated. Manufacturer. https://www.goudsmitmagnetics.com/en-us/products/belt-conveyor-magnetic-separators/eddyfines-eddy-current-separators. Read 2026-10-06.
  20. Eriez. Eddy Current Separator, REA Cartridge Design: Installation, Operation and Maintenance, SM-780-1. 2010. Manufacturer. https://www.eriez.com/Documents/Literature/IOMs/Metals-Recycling/SM-780-1-Eriez-Eddy-Current-Separator-REA-Cartridge-Design-IOM.pdf. Read 2026-10-06.
  21. Remcon Equipment, Inc., the publisher's affiliate. Eddy Current Separators for Aluminum Recycling. Undated. The affiliate's own site. https://www.remconequipment.com/eddy-current-aluminum-separators. Read 2026-10-06.

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