EFFICIENT USE OF ALUMINUM SCRAP IN EFFICIENT USE OF ALUMINUM SCRAP - - PowerPoint PPT Presentation
EFFICIENT USE OF ALUMINUM SCRAP IN EFFICIENT USE OF ALUMINUM SCRAP IN BATCHING SECONDARY ALLOYS AND POTENTIAL BATCHING SECONDARY ALLOYS AND POTENTIAL FOR SENSOR-BASED SORTERS TO IMPROVE FOR SENSOR-BASED SORTERS TO IMPROVE RECYCLING SYSTEM
REWAS 2008, Cancun
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Hartmut Harbeck TiTech GmbH Adam Gesing Gesing Consultants Inc
REWAS 2008, Cancun
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Aluminum p Aluminum prod
uction and recycling Remelt and ingot cast house Semi- fabricator Component manufacturer Assembler Use Shape caster Dross processor Prime smelter Scrap dealer Landfill Casting scrap Dross Shredder Sorter Fab scrap Manuf scrap Mixed manuf scrap Reject components Assembly scrap Oxides Salts Foils Chips Turnings Contaminated scrap RSI Al shred EoL scrap Waste EoL & mixed metal scrap Handsorted Al scrap Shredder residues
REWAS 2008, Cancun
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REWAS 2008, Cancun
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Post-consumer light-metal scrap sources Post-consumer light-metal scrap sources
Al or Mg alloys batched from alloy mix Alloy sorting/batching plants Al and Mg-Al mixes from shredder LM concentrate Dense media sink-float plants LM scrap products NMMC (nonmagnetic metal concentrate) LM concentrate Steel shredders LM commingled in shredded scrap Flattened ELV hulks Handsorted & baled, categorized LM scrap Scrap yards and ELV de-pollution dismantlers Electronic scrap – Al and Mg housings WEEE recycling depots Building scrap, siding, windows, doors Scrap machinery, process vessels & piping C&D MRFs Consumer durables – appliances Municipal waste dirty MRFs and RDF plants UBC Packaging foil Curbside recycling and recycling depots LM in EoL products Scrap type Scrap source
Post-consumer scrap diverted from landfill and recycled reduces demand for the prime metal by secondary alloys and frees up prime for use in high-performance prime alloys
REWAS 2008, Cancun
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Light metals in the car recycling system Light metals in the car recycling system
ELV Deregistration Depollution Dismantling Flattening reusable components fluids refrigerants catalysts toxics flattened ELV hulk scrapped parts steel shred nonmagnetic metal concentrate steel scrap demolition scrap appliance scrap Steel shredder Car repair Sink-float media plant Mg / Al(Mg) in nonmetal residue dense metals wire Al refiner Si Zn Cu Cl2 Al new &
Al 38X & 319 foundry ingot Al shape casting Al prime ingot Al casting scrap
Al castings MgCl2 in dross
mixed metal scrap Al(Mg) + Al(SiCuZn)
Mg+Al mix
Remanufacture remanufactured parts Remanufacturing scrap Scrap yard direct to remelt categorized scrap nonmetal residue used consumer scrap used industrial scrap Al+(Mg).
Car in use
Car repair Remanufacture Deregistration Depollution Dismantling Flattening Car repair Remanufacture Steel shredder Al refiner Scrap yard Deregistration Depollution Dismantling Flattening Car repair Remanufacture Al shape casting Steel shredder Al refiner Scrap yard Deregistration Depollution Dismantling Flattening Car repair Remanufacture
Sink-float media plant Al shape casting Steel shredder Al refiner Scrap yard Deregistration Depollution Dismantling Flattening Car repair Remanufacture
REWAS 2008, Cancun
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5,000-15,000 HP hammer mill Cyclone & baghouse Overbelt magnet Nonmetal fines drum magnet
Steel
ELVs
steel <5 mm fines (nonmetal)
NMMC nonmagnetic metal concentrate
Light SR Oversize 5, 30 mm screens >30<100 mm >5<30 mm Eddy current rotor circuit Nonmetal lead, wire stainless steel Z-box elutriator Eddy current coil particle sorter circuit Stainless steel
Al + Mg concentrate
white goods MSW mixed metal dealer scrap CDW light SR metal steel Nonmetal
Nonmagnetic shredder fraction –NA supply ~ 1,000 kT of NF metal/ year, growing quickly –20-95% metal –60-70% Al in metal (~ 600 kT/ year) –30-50% wrought in Al (~ 200 kT/ year)
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Sink-float dense Sink-float dense-media plant media plant
1000-2000 HP hammer mill Cyclone separator & baghouse 3 mm screen Overbelt magnet Nonmetal fines & dust foam paper foil textile Nonmetal rock Overbelt magnet steel Oversize
NMMC from SLF NMMC from SDF
steel fines light dense 100 mm 3 mm screens Eddy current rotor and shape sort circuit
Al alloy mix
Dense metal mix Nonmetal Insul. Wire
1.0 g/cc wash
9 mm screen
2.0 g/cc
magnetite slurry headpulley magnet
3.5 g/cc
ferrosilicon slurry Eddy current rotor circuit float Fe attach.
Al +Mg mix
float Jig Nonmetal grain Eddy current rotor circuit
Al +Mg grain
<9 mm metal mix dense light Process water treatment Dewatered sludge >9 mm NMMC = Nonmagnetic metal concentrate
REWAS 2008, Cancun
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This specification can be met by many mixtures of old wrought alloy scrap
95% Al Steel deoxidants
Tighter concentration limits on 319 increase the dilution requirement and limit the types of old scrap that can be added to a 319 alloy batch
319.x casting
Some 38X alloys can accept a mixture of the most common old scrap varieties without dilution, providing the Mg concentration is controlled by chlorination
38X.x casting alloys Automotive Al
Old Al siding Al siding and extrusion construction scrap Mixed wrought manufacturing Al scrap with low copper content Old wrought scrap
3105 painted sheet Building Al
Old cans, can manufacturing scrap Non-can wrought manufacturing scrap Al- and Mg-based scrap mix from 2 g/cc float fraction of a dense-media sink-float plant
3X04 can body sheet Al packaging Compatible scrap sources Secondary alloy Market
REWAS 2008, Cancun
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REWAS 2008, Cancun
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Alternative uses for prim Alternative uses for primary Al ingot & recycled Al ary Al ingot & recycled Al
Primary imary Al ingot Al ingot
Mg extrusion mill remelt Mg sheet mill remelt Mg shape casting remelt Al extrusion mill remelt Al sheet mill remelt Al shape casting remelt
Al in Mg AZ91 particle- batched
Al UBC remelt
Mg +Al particle mix
from light media float Al 5/6XXX particle batched old shred Al 3/5/6XXX particle batched old shred Al 3XX particle batched old shred Al 3X04 particle batched old shred Al in Mg alloy- segregated ingot and shape casting scrap Al in Mg alloy- segregated ingot casting fabrication & manufacturing scrap Al in Mg alloy- segregated billet casting fabrication & manufacturing scrap Al alloy- segregated ingot casting fabrication & manufacturing scrap Al alloy- segregated billet casting fabrication & manufacturing scrap UBC
Al secondary smelter
deoxidant
Al 3XX alloy- segregated casting & manufacturing scrap Al dross and skim Fe contaminated scrap Al machining chips & turnings Al machining chips & turnings
REWAS 2008, Cancun
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REWAS 2008, Cancun
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foundry alloys
foundry alloys, is a mixture of scrap from ELVs, C&D and appliances
product or market, is often used in diluting automotive foundry alloys
is used in batching automotive 38X foundry alloys
REWAS 2008, Cancun
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REWAS 2008, Cancun
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REWAS 2008, Cancun
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landfills
system and scrap markets
have an existing destination in the current system
scrap and use this scrap to alloy new metal
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1 2 3 1
Unsorted particle feed
2
Scanning and processing
3
Diversion
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Air jet ejection Conveyor Sorted Products Sorted Products Sorted Products Sorted Products Conveyor Sorted Products Air jet ejection Conveyor Sorted Products ECC sensor Mixed feed Find metal in residue and/or separate stainless steel
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Air jet ejection Conveyor Sorted Products Sorted Products Sorted Products Sorted Products Conveyor Sorted Products Air jet ejection Conveyor Sorted Products ECC sensor Mixed feed Color sensor Illumination Separate Cu, brass, Zn, stainless steel, nonmetal
Al, Mg and nonmetal
REWAS 2008, Cancun
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Mixed feed Air jet ejection Conveyor Sorted Products Sorted Products Sorted Products Mixed feed Sorted Products Conveyor Mixed feed Sorted Products Air jet ejection Conveyor X-ray illumination Sorted products DE sensor Mixed feed Identify contaminants attachments, Separate light metals from dense metals
REWAS 2008, Cancun
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REWAS 2008, Cancun
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Mixed feed Air jet ejection Conveyor Sorted Products Sorted Products Sorted Products Mixed feed Sorted Products Conveyor Mixed feed Sorted Products Air jet ejection Conveyor Sorted products OE spectrometer Mixed feed XYZ scanner LASER illumination Camera
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Sorters with three diversion blowbars are already successfully
the feed into four output streams typically:
Mix of two or a maximum of three alloys can be sorted in a single pass through the sorter.
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When more alloys are present in the sorter feed stream, one has the option of:
more sorted alloys
make two new output alloys
A sorter batches these alloys on line, particle by particle. The result
ready market. Old post-consumer scrap contains a large variety of alloys and their particular variants. Sorting of old scrap by alloy really is not a practical option. It is batching that enables upgrading of complex mixtures of both old and new scrap.
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REWAS 2008, Cancun
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Sorter Optimum Performance Curve
0 Component recovery (%) 100 0 Product grade (%) 100
Circuit optimum performance curve Feed mix Prepare feed PS mix product PS mix Clean residue Clean product
REWAS 2008, Cancun
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REWAS 2008, Cancun
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Contents 1000-2000 HP hammer mill Cyclone separator & baghouse 3 mm screen Overbelt magnet Nonmetal fines & dust foam paper foil textile Nonmetal Overbelt magnet Steel Oversize NMMC from SLF NMMC from SDF steel <3 mm fines >3<9 mm metal mix light dense Oversize 30 mm 9 mm fines screens >9<30 mm >30<100 mm >3<9 mm Eddy current rotor circuit magnetic nonmetal Headpulley magnet Eddy current coil particle sorter circuit Stainless steel >9<100 mm metal mix DE x-ray sensor particle sorter circuit
Al- alloy mix Mg- alloy mix
Dense metal mix Wire contaminated NMMC = Nonmagnetic metal concentrate
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1000-2000 HP hammer mill Al fines Overbelt magnet steel Oversize Mg steel >3<9 mm Al mix Oversize 30 mm 9 mm fines screens >9<30 mm >30<100 mm >3<9 mm Eddy current rotor circuit attached steel stainless steel Nonmetal Headpulley magnet >9<100 mm Mg / Mg+Al / Al DE x-ray sensor particle sorter circuit Al-alloy mix Mg-alloy mix Clean LIBS sensor elemental composition particle sorter circuit Al alloy 1 Al alloy 2 Al- alloy mix Mg alloy 1 Mg alloy 2 Mg- alloy mix Contaminated Mg + Al <3 mm fines Mg fines >3<9 mm Mg mix Dense Metals
REWAS 2008, Cancun
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Recovery of recyclables from landfilled post-consumer waste Residual metal removal from shredder residue Al dross processing Separation of bare and painted scrap Separation of nonmetal contaminants and attachments Contaminant removal from nominally source-segregated manufacturing alloy scrap Sorting of mixed-alloy manufacturing scrap Separation of free Mg from Al scrap Separation of Al alloys with high Mg content from those with high Si, Cu or Zn in Al scrap Batching of value-added secondary alloys from post-consumer Al scrap twitch, old sheet and cast
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Landfilled in USA in 2006
In municipal recycling facilities (MRFs), thousands of sensor-based sorters already
from curbside collected recyclables. These sensor-based sorters could also deal with recyclables from landfilled waste.
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Primary shredder feed consists of steel containing ~25% nonmetallic and 5-10% nonmagnetic metals. Even a small concentration of nonmagnetic metal in the nonmetallic residue can represent significant loss of recovery of the nonmagnetic metals. Eddy current coil (ECC) sensor sorters inspect and recover the residual metal from nonmetallic residue. The dual energy x-ray transmission (DE-XRT) sensor could separate light from dense metals, replacing the function of the dense-media sink-float plants. Dual sensor ECC and DE-XRT sensors have the resolution and capability to inspect shredder fines residue that still contains small copper wires and small Al particles.
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USGS data for 2006 reports over 600 kt of metal recovered from dross and skimmings. The US residue consists of more than 1,500 kt of nonmetallics containing up to 30 kt of metal. Prior to being remelted in rotary furnaces, Al metal is typically concentrated by crushing dross and eddy current rotor separation (ECS). This mechanical separation is sometimes repeated for the rotary furnace dross or saltcake. Dual sensor ECC and DE-XRT sorters have the resolution and capability to inspect crushed oxides and saltcake for residual metal.
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Al from old post-consumer scrap is a mixture of bare and painted items. Decoating of bare scrap is a waste of effort and energy, while melting of painted scrap results in excessive melt losses. US Al smelters in 2006 consumed 215 kT of non-UBC wrought old scrap and 155 kT of cast old scrap. Much of this scrap could benefit from bare/painted separation and decoating of the painted fraction. A particle sorter equipped with a color camera sensor could separation after the material is shredded and sized. Reduction in melt losses is more than adequate to offset the additional processing costs.
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Wire and PCBs are difficult segregate from Al by bulk sorting. They represent losses of valuable resources and contaminate the melt. Metal attachments dissolve to contaminate the product melt. Residual paper, plastic and rubber particles and attachments in Al scrap burn during remelting, leading to oxidation and melt losses. Inorganics react with metal, contaminating it, and end up as dross. The 190 kT of Al recovered from shredder metal concentrate and consumed in US in 2006 could have been melted with lower melt losses and contamination if the residual contaminants were sorted
Another 1,000 kT of other Al old scrap consumed in US in 2006 would need to be shredded to permit removal of contaminants and attachments. A particle sorter equipped with a DE-XRT sensor is up to this task.
REWAS 2008, Cancun
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REWAS 2008, Cancun
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Without Al-Mg separation, 200 kT of Mg diecastings that have entered the automotive market in 2008 will in the future contaminate over 5,000 kT of Al automotive Al scrap and will lead to losses of the 200 kT of Mg and similar amounts of Al in refining by chlorination. In the near future, Al-Mg separation will become imperative to maintain the efficiency and sustainability of the light-metal lifecycle. Options for Al-Mg segregation are either density separation in a dense-media plant or sensor-based sorting. Only a few media plants are left in North America and no new ones are being built. This leaves sensor-based particle sorting, where a combination of color and DE-XRT sensors can do the sort.
REWAS 2008, Cancun
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REWAS 2008, Cancun
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The current level of refining by chlorination and the associated losses can be substantially reduced by sorting out Al-alloy particles rich in Mg and batching them into secondary wrought alloys. 3X04 can body sheet and 3105 building sheet are suitable candidate alloys. The second output stream will be high in Si, Cu and Zn and low in Mg, giving it an added value when batching foundry alloys. Such batching can be performed by a LIBS sensor. The first industrial plant based on this technology was commissioned in 2004 by Huron Valley Steel Corp. in Belleville, MI, and has been successfully operating since then on a feed of Al recovered from shredder metal concentrate.
REWAS 2008, Cancun
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A secondary smelter equipped with a LIBS sensor particle sorting circuit has the freedom to buy post-consumer Al scrap from scrap dealers, which includes shredder product plus old sheet, extrusion and cast categories. Through elemental particle analysis, a LIBS sensor could batch value added two alloys at a time from this lower cost scrap. The key to such batching process economics is the price margin between the LME 380 alloy ingot and the price that the smelter can
these products.
Scale and radiation detector 1000-2000 HP hammer mill nonmetal Overbelt magnet steel Oversi ze steel lead <3 fines >3<9 mm metal mix Cu Oversize 30 mm 9 mm fines screens >9<30 mm >30<100 mm >3<9mm Eddy current rotor circuit attached steel stainless steel Nonmetal lead wire stainless steel Headpulley magnet Eddy current coil particle sorter circuit attached steel re- shred wire >9<100 mm metal mix DE –X-ray sensor particle sorter circuit Al Mg Dense metal mix XRF sensor elemental composition particle sorter circuit red brass yellow brass Color sensor particle sorter circuit Red Whit e Zn stainless steel Dense metal mix (dense media sink) Dense metal mix (dry sort) DE –X-ray sensor particle sorter circuit Al + Mg (light media float)
REWAS 2008, Cancun
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REWAS 2008, Cancun
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REWAS 2008, Cancun
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Collection & de-pollution Feedstock production Material production Semi-product fabrication Energy recovery Mechanical segregation Manufacturing Construction Assembly