particle sorting of light-metal alloys rewas 81010gesingconsultants.com/publications/light metal...
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REWAS 200812-15 October, Cancun
esingonsultants Inc
PARTICLE SORTING OF LIGHT-METAL ALLOYSAND EXPANDED USE OF MANUFACTURING
SCRAP IN AUTOMOTIVE, MARINE AND AEROSPACE MARKETS
Hartmut HarbeckTiTech GmbH
Adam GesingGesing Consultants Inc
REWAS 200812-15 October, Cancun
esingonsultants Inc
Value-added markets: Al-intensive vehicles
REWAS 200812-15 October, Cancun
esingonsultants Inc
Value-added markets: Al-intensive vehicles
REWAS 200812-15 October, Cancun
esingonsultants Inc
Value-added markets: Al-intensive vehicles
REWAS 200812-15 October, Cancun
esingonsultants Inc
Value-added markets: Al-intensive vehicles
REWAS 200812-15 October, Cancun
esingonsultants Inc
Value-added markets: Al-intensive vehicles
REWAS 200812-15 October, Cancun
esingonsultants Inc
Use of Al- and Mg-based alloys in automotive components
AE41, AE44 (Mg-Al-RE)Creep-resistant castings
AJ62 (Mg-Al-Sr-Ca)
AZxy, AZ91 (Mg-Al-Zn-Mn)
x<4 sheet and extrusionsx>4 castings
AMxy, AM60 (Mg-Al-Mn)Mg
brazed heat exchangers1100/4147, 3003/4147
extrusions6061, 6082, 7004, 7008, 7129
stiffener sheet5182, 5754
closure sheet6016, 6111
cast wheelsA356.2
power train castings38X.0, 319, 356Al
ApplicationAlloyParent
REWAS 200812-15 October, Cancun
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Value-added markets: Al-intensive vehicles
REWAS 200812-15 October, Cancun
esingonsultants Inc
Value-added markets: Al-intensive vehicles
REWAS 200812-15 October, Cancun
esingonsultants Inc
Al alloys dominant in marine market
extrusions: spars, structural stiffeners6061, 60636XXX
sheet and plate: hulls, superstructures5052, 5X56, 5X83, 5X865XXX
ApplicationsAlloysAlloy
Family
REWAS 200812-15 October, Cancun
esingonsultants Inc
Value-added markets: Al-intensive vehicles
REWAS 200812-15 October, Cancun
esingonsultants Inc
Value-added markets: Al-intensive vehicles
REWAS 200812-15 October, Cancun
esingonsultants Inc
Use of Al- and Mg-based alloys in aerospace components
creep-resistant castingsAE41, AE44Mg + Al + RE
sheet and plate6061
extrusions6056, 6061Al + Mg + Si
sheet5086Al + Mg
extrusions2X96, 2099
sheet and plate2050, 2X95, 2090, 2X98Al + Li
extrusions, sheet7X50, 7055, 7X75
sheet and plate7010, 7X50, 7X75Al + Zn
extrusions2014, 2X18 2024, 2026
sheet and plate2X14, 2X19, 2X24Al + Cu
ApplicationAlloyAlloy Family
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esingonsultants Inc
Secondary die castings
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Aluminum production and recycling
Remelt and ingot casthouse
Semi-fabricator
Component manufacturer
Assembler
Use
Shape caster
Dross processor
Prime smelter
Scrap dealer
Landfill
Casting scrap
Dross
Shredder Sorter
Fabscrap
Manufscrap
Mixedmanufscrap
Reject componentsAssembly
scrap
Oxides Salts
FoilsChips
TurningsContaminated
scrap
RSI
Alshred
EoLscrap
Waste
EoL & mixed metal scrap
Handsorted Alscrap
Shredder
residues
REWAS 200812-15 October, Cancun
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Quantities of new fabrication and manufacturing scrap
A mass balance of global Al flows done around 2005 demonstrated that new scrap represents >50% of prime metal production at ~21,000 kt. This was three times as much metal as was recovered from old post-consumer scrap.
Mg-based alloys consume currently ~300 kt of prime Mg and result in ~200 kt of die trim and machining chips.
New scrap has a significant advantage over post-consumer scrap in that it is already collected at the fabrication and manufacturing locations, is generally more predictably contaminated, and is not corroded.
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Production and manufacturing scrap sources
• Primary smelter dross• Remelt and secondary smelter dross and skim• Ingot/billet casting scrap• Shape casting scrap• Semi-fabrication scrap• Manufacturing scrap
Prompt and manufacturing scrap quantity is large (~3 × old scrap).
Metal production and semi-fabrication scrap either is or should be alloy segregated at source.
Manufacturing scrap often is a simple mixture of known metals and alloys.
Scrap is usually surface contaminated: oily, lubricated or coated with paint, paper or plastic. Scrap should be cleaned, preferably before sorting, but definitely before remelting.All metal separated from production or manufacturing scrap is already recycled, some of it closed-loop into a similar alloy.
REWAS 200812-15 October, Cancun
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New scrap
New scrap generation has immediate financial impact on product component costs.
Manufacturers purchase metal for their products – and the resulting scrap – at a high price that includes the cost of production of the prime metal, and all metal fabrication steps
Manufacturers then sell the new scrap at a discount to prime metal. The size of the discount depends on how clean the scrap is and if it is segregated by alloy or sold as a mixture.
In this way scrap generators pay more, while scrap recyclers could the benefit of the discount when they batch secondary alloys from scrap.
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Segregation by alloy at sourceAt source, the composition of each alloy is known to a better precision than can be determined by on-line sensors.
Segregation by alloy at source is always preferable to later sorting.
Alloy segregation is typically practiced at the semi-fabrication plants. Mistakes and mix-ups still sometimes happen.
Logistically, scrap segregation by alloy is difficult in large machining shops and stamping plants. When source segregation is attempted, mistakes often happen.
REWAS 200812-15 October, Cancun
esingonsultants Inc
Mixed-alloy scrapOccasionally mixed-alloy new scrap has an average composition that is compatible with an alloy with a higher alloying element content, and can be used directly in batching this alloy without sorting.
This is a case for used beverage cans, where the average can composition can be used for batching the can body alloy.
However, these cases are exceptions, and more commonly new mixed metal scrap is sold at a discount to be used later for secondary foundry alloy or painted building sheet applications.
To recover full material value and keep this metal in marine and automotive wrought product markets, sorting of mixed scrap will usually be necessary.
REWAS 200812-15 October, Cancun
esingonsultants Inc
Sorting technology –current commercial practice
REWAS 200812-15 October, Cancun
esingonsultants Inc
Chute type particle sorter
1 Unsorted particle feed2 Scanning and processing3 Diversion
1
2
3
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esingonsultants Inc
Belt type particle sorter
1 2 3
1 Unsorted particle feed2 Scanning and processing3 Diversion
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esingonsultants Inc
Sensors suitable for scrap sorting tasksThere are a number of sensors that can remotely inspect and analyse particles distributed on a conveyor belt, sliding down achute or in free fall.Vision 2-D and 3-D sensors identify shape and size of individual particles. In new scrap there may be a consistent correlation between the metal/alloy type and the shape/size of scrap pieces.In cases where such a correlation exists sorting by shape is one of the most cost-effective options.Colour or gray-scale sensors identify painted particles and contaminants and sort by parent metal (Mg, Al, Zn, Cu, Fe). Sometimes, during a pre-cleaning step, the scrap surface is chemically altered to selectively tint different alloys in the mix.X-ray transmission sensors are able to look through light-metal particles. This enables the sensors to identify attachments or contaminant particles; sort by wall thickness; separate light metal from dense metal; Al from Mg; and Al alloys with Mg or Si only from Al alloys that contain dense alloying elements such as Cu and/orZn.
REWAS 200812-15 October, Cancun
esingonsultants Inc
FinderEddy-current coil sensor
sorter
Air jet ejection
Conveyor
Sorted ProductsSorted
ProductsSorted
ProductsSorted
Products
Conveyor
Sorted Products
Air jet ejection
Conveyor
Sorted Products
ECC sensor
Mixed feed
Find metal in residue
and/or
separate stainless steel
Potential for grouping some non-ferrous
metals
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esingonsultants Inc
CombiSenseColor and ECC sensor sorter
Air jet ejection
Conveyor
Sorted ProductsSorted
ProductsSorted
ProductsSorted
Products
Conveyor
Sorted Products
Air jet ejection
Conveyor
Sorted Products
ECC sensor
Mixed feed
Color sensor
Illumination
Separate Cu, brass, Zn, stainless
steel, nonmetal
or
Al, Mg and nonmetal
REWAS 200812-15 October, Cancun
esingonsultants Inc
X-Tractdual energy x-ray
transmission sensor sorter
Mixed feed
Air jet ejection
Conveyor
Sorted ProductsSorted
ProductsSorted
Products
Mixed feed Sorted
Products
Conveyor
Mixed feed Sorted
Products
Air jet ejection
Conveyor
X-Ray Illumination
Sorted Products
DE sensor
Mixed feedIdentify
contaminants,
attachments,
separate light metals from dense metals
REWAS 200812-15 October, Cancun
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DE-XRT identification of Al and Mg
REWAS 200812-15 October, Cancun
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Elemental composition sensors
Elemental composition sensors enable separation of alloy mixtures that are not separable by physical shape or colour or X-ray absorption.For new scrap mixtures consisting of few known alloys, calculation of the actual elemental concentrations is not necessary.It is adequate to base the sort on the alloy spectral fingerprint.This significantly simplifies the complexity of the sorting task, as compared with trying to batch an alloy from a mixture of scrap particles of many unknown alloy compositions.
REWAS 200812-15 October, Cancun
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Elemental composition sensors:X-ray fluorescence sensor (XRF)
Used for discrimination based on high (>18) atomic number alloying elements.
In air XRF can remotely sense characteristic x-rays from Ti, Mn, Fe, Cu, Ni, Zn and denser elements.
Air absorbs low-energy x-rays from light metal elements such as Li, Mg, Al and Si.
XRF sensors have limited usefulness for Al- and Mg-based alloys.
REWAS 200812-15 October, Cancun
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Elemental composition sensorsLaser-induced plasma spectroscopy (LIBS)
The optical emission from a plasma spark generated by the ablation laser impact is spectroscopically analysed.
All alloying elements of interest can be detected by optical emission spectroscopy.
LIBS technique is used where discrimination based on light alloying elements (Li, Mg, Al and Si) is necessary.
REWAS 200812-15 October, Cancun
esingonsultants Inc
Elemental concentration sensor sorters
XRF sensor
Alloy sort based on analysis of dense
elements
Mixed feed
Air jet ejection
Conveyor
Sorted ProductsSorted
ProductsSorted
Products
Mixed feed Sorted
Products
Conveyor
Mixed feed Sorted
Products
Air jet ejection
Conveyor
X-Ray Illumination
Sorted Products
XRF array sensor
Mixed feed
Mixed feed
Air jet ejection
Conveyor
Sorted ProductsSorted
ProductsSorted
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
LIBS sensor
Alloy sort based on analysis of all
elements,
light and dense
REWAS 200812-15 October, Cancun
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Competition:Sorting table vs Sorting circuit
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Sorting circuits
In order to provide sorted products with an acceptable combination of recovery and product purity, sorters are arranged in a circuit with auxiliary unit operations. A typical dry sorting circuit for light-metal scrap might include following unit operations:
• Particle sizing – size reduction and size separation
• Clean and dry – removing cutting fluids and forming lubricants from new scrap
• Sort out non-Al contaminants from Al-alloy mix
• Sort mix by alloy or batch target alloy(s) from the mix
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LM alloy batching/sorting plant
1000-2000 HP hammer mill
Al fines
Overbelt magnet
steel
Oversize
Mg
steel
>3<9 mm Al mix
Oversize30 mm 9 mmfines
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 sensorparticle 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
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esingonsultants Inc
Sorting circuit
Sorter Optimum Performance Curve
0 Component Recovery (%) 100
0
Pr
oduc
t Gra
de (%
)
100
Circuit Optimum Performance Curve Feed mix
Prepare Feed
PS mix
product
PS mix
Clean Residue
Clean product
REWAS 200812-15 October, Cancun
esingonsultants Inc
Scrap sorting plant (current technology)
Scale and radiation detector
1000-2000 HP hammer mill
nonmetal
Overbelt magnet
steel
Oversize
steel
lead
<3 fines
>3<9 mm
metal mix
Cu
Oversize30 mm 9 mmfines
screens
>9<30 mm
>30<100 mm
>3<9mm
Eddy current
rotor circuit
attached steel
stainless steelNonmetal
lead wire
stainless steel
Headpulley magnet
Eddy current coil particle sorter circuit
attached steel re-
shred
wire
>9<100 mm metal mixDE –X-ray
sensorparticle sorter
circuit
Al Mg
Dense metal mix
XRF sensor elemental
composition particle sorter
circuit
red brass
yellow brass
Color sensorparticle sorter
circuit
Red White
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 200812-15 October, Cancun
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Desirable and feasible separations for new scrap:Impurity removal
Impurity separation from purchased new scrap, nominally alloy-segregated at source(nonmetal, other metals, other alloys of the same metal, pieces with “other” attachments, dirty, painted or coated) from (2024, 3003, 5754, 5182, 5052, 5083, 5086, 6061, 6082, 6022, 6111, 6016, 7004, 7008) Small quantity of impurity from large quantity of good material. Economic for small particle sorting.
colourdirty, painted or coated
XRT, LIBS,XRFother alloy
eddy current rotor nonmetal
XRTpieces with attachments
colour, XRT, eddy current coilother metal
howwhat
Remove
REWAS 200812-15 October, Cancun
esingonsultants Inc
Desirable and feasible separations for new scrap:Sorting of new scrap
XRT, color
Machining chips, turnings 6063, 6061 from 2024, 7050, 7075,
356 from 319, 38X
Al from brass, st. steel, zinc
LIBS Stamping skeletons: Automotive: 6111 from 5754
XRT, LIBS
Sprues, gates, mold trim,
356, 319, 38X, 413
LIBSCutting trim: Aerospace:2024 from 7050 & from 7075,
Marine: 5083 from 5086
howwhat
SortSorting among known alloys of new, mixed-alloy scrap
Similar quantities of known alloys.
Economic for sorting of larger particle.
REWAS 200812-15 October, Cancun
esingonsultants Inc
ConclusionsManufacturing of aerospace, marine and automotive components results in generation of large quantities of new scrap.
Source segregation of scrap by alloy is desirable but often not practical
Sorting of scrap to maintain its value is usually more cost effective than
Sorters that can identify and remove impurities are already commercially available and proven in large tonnage industrial applications.
Sorters that enable sorting by alloy have also been proven and commercial units are under development.
REWAS 200812-15 October, Cancun
esingonsultants Inc
Conclusions Source segregated fabrication scrap is routinely used in batching aerospace marine and automotive alloys
Sorting of new scrap mixed manufacturing can significantly increase the quantity of light metal scrap that is practical to use as starting material for value added alloys for production of cars, boats and airplanes.
REWAS 200812-15 October, Cancun
esingonsultants Inc
Consumer
Collection & de-pollution
Feedstockproduction
Material production
Semi-productfabrication
Energy recovery
Mechanical segregation
ManufacturingConstruction
Assembly
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