RECYCLING VALUABLE METALS FROM
BY-PRODUCTS
RODRIGUEZ David
SEAISI 2010 (Manila) – November 23rd, 2010
© Paul Wurth 2010
INDUSTRIAL RESIDUES SITUATION
 Industrials are facing more and more
stringent environmental regulations
 Dumping costs and creates environmental
liabilities
 Extraction of valuable metals contained in
residues generates financial return
 Look for an alternative to high cost of
“virgin” raw material
Challenge: solve both environmental and
economical issues
© Paul Wurth 2010
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OVERVIEW OF RESIDUES
Type of waste
Recoverable
metals
Remarks
Ni, Cr, Mo, Fe
Small quantities
Recycling economical
High product value
1
From the stainless or high
alloy steel industry
2
From electric steel plants
making carbon steel
(EAF dust)
Zn, (Fe)
Larger quantities
Economics depend on Zn price
(treatment fee required)
3
From integrated steel plants
Fe
Very large quantities
Economics not always favourable
4
From petrochemical industry
(Spent catalysts)
Mo, Ni, Co, V
Small quantities
High product value
5
From Copper industry
Cu, (Mo)
Very large quantity
High product value
6
From Zn hydrometallurgy
Zn, Pb, Fe, Ag
Larger quantities
Economics depend on Zn, Fe prices
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PAUL WURTH EXPERIENCE IN STEELMAKING BY-PRODUCTS
 Activity began 15 years ago
 Recycling technologies:
 RHF technologies: RedSmelt™ / RedIron™
60ktpy RedIron plant in Piombino (IT - 2010)
Recycling of integrated steelmaking residues
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PAUL WURTH EXPERIENCE IN STEELMAKING BY-PRODUCTS
 Recycling technologies:
 Primus® technology: MHF + EAF
75 ktpy Primus® plant in Differdange (LU - 2003)
Recycling of EAF dust (60 ktpy) and oily mill sludge (15 ktpy)
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PAUL WURTH NEW PROCESS DEVELOPMENTS
 i-Meltor™ furnace
 Adapted AC EAF equipped with bottom gas stirring
and central charging between 3 electrodes
 Combined in Primus process with MHF or used as
stand-alone
 PLD process
 PLD: Paul Wurth Lhoist Deoiling
 Recycling of oily mill sludge and scales in partnership
with Lhoist R&D (Worldwide leader in CaO/MgO
based products)
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PAUL WURTH NEW PROCESS DEVELOPMENTS
i-MELTOR™
Intensive Melting Reactor
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i-MELTOR™ FURNACE
Specific electric arc furnace for reducingmelting-settling-fuming of slag & residues
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i-MELTOR™ : Main components
Central charging duct
Graphite electrode
Electrodes arms
Process offgas outlet
Water cooled cover
Slag
Spray coolers
Slag door
Hot metal
Refractory lining
Transfer car
Bottom gas stirring
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i-MELTOR™ : Process key features
 Central charging
 Accept fines
 High specific power 1 MW/m2
 Compact design
 Controlled bottom gas stirring
 Enable multi-step processes (melting, reducing, refining,
settling, fuming)
Combination of these 3 key features
ensures high melting kinetics
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i-MELTOR™ : References
6 t pilot EAF
PRIMOREC EAF
DSC EAF
Ø2m int.
3 MW
Ø3,5m int.
10 MW
Ø6m int.
21 MW
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i-MELTOR™ : Technological highlights
 Spray coolers
 Key features
• Increased lifetime of refractory lining in the slag zone
• Pressure less cooling system
• Operated in safe conditions in case of breakthrough
With staves
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Recycling valuable metals from by-products SEAISI2010
Without staves
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i-MELTOR™ : Technological highlights
 Offgas cleaning system
 Components
Quench
Water cooled elbow + jacket
Post combustion chamber
Quench tower
Baghouse filter
PCC
•
•
•
•
Filter unit
Adapted to comply with lowest emission limits
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i-MELTOR™ : Opportunities
© Paul Wurth 2010
EAF dust
SS dust &
sludge
Waelz slag
Fe
Zn
Ni
Cr
Zn
Fe
Zn
Spent
catalysts
Cu slag &
residues
Leaching
residues
Mo
Ni
Co
Cu Ni
Mo Zn
Zn Ag
In
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i-MELTOR™ : Applications - Recycling of stainless steel dust and sludge
Application
SS dust &
sludge
 In place of SAF
 Input: 80-200kt/y pre-reduced product
SS dust &
sludge
 Output: NiCr alloy
Application
 Input: dust with 4% Zn, 4% Cr and 2% Ni
ZnO
 Output: NiCr alloy and ZnO
ZnO
NiCr
alloy
© Paul Wurth 2010
Inert
slag
 10 to 70 kty dust
NiCr
alloy
Recycling valuable metals from by-products SEAISI2010
Inert
slag
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PAUL WURTH NEW PROCESS DEVELOPMENTS
PLD PROCESS
Paul Wurth Lhoist Deoiling
© Paul Wurth 2010
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Oily sludge & scales - Treatment
sinter
 Energy
consumption
coking coal
Ore
Limited (Dioxins)
 Requires hard briquettes
coke
 Reduces burden permeability
 Penalizes BF performances
 Reduces PCI capacity
High T° Pyroprocesses
 Requires more coke
hot metal
 Abrasion issue
 Requires charge preparation
 Disturbs process
 Impacts steel quality (S)
Oily scale / sludge
 Cost
 Liabilities
© Paul Wurth 2010
Recycling valuable metals from by-products SEAISI2010
dump
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PLD PROCESS : Basic principles
Oily by-product
HC: 2-20%
H2O: 10-30%
Air
Offgas
CO < 50 ppm
VOC < 10 ppm
MIXING
SELF-HEATING
SOFT CONTROLLED
OXIDIZING
CaO: 5-15%
Up to 500°C
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Recycling valuable metals from by-products SEAISI2010
Dry powder
HC < 0,1%
CaCO3
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PLD PROCESS : Driving parameters
Quantity of CaO
Residence
Time
Air injection
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PLD PROCESS : Test performances – Continuous pilot test
Trial #2
Trial #3
#4
Trial #5
#6
#7
600
Sludge: 18~20% oil; 20% H2O
500
Scales: 1~2% oil; 2~10% H2O
400
Mix: 2-4-8-10% oil; 9-11-20% H2O
29/10/2009 14:00
29/10/2009 06:00
28/10/2009 22:00
28/10/2009 14:00
28/10/2009 06:00
27/10/2009 22:00
27/10/2009 14:00
Main conclusions:
 Auto thermal process proven
 Throughput: 100 kg mix/h
 De-oiling down
to 0.1% achieved
+ 0 - 5 - 10% lime
 Residence time: 60 min
 PC of offgas efficient
27/10/2009 06:00
200
26/10/2009 22:00
300
26/10/2009 14:00
Average furnace temperature (°C)
Trial #1
Time
 Test duration: 4 Days
 Temperatures : 500 - 400 - 300 °C
2 Continuous test
campaigns:
8 hours / 4 days
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PLD PROCESS : Industrial plant flowsheet
Lime
Handling
Material
Handling
Sludge
Handling
Offgas
MHF
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PLD PROCESS : Industrial plant layout
Sludge
Handling
Lime
Handling
~ 20 m
Offgas
MHF
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PLD PROCESS : Industrial plant typical design
• Multiple Hearth Furnace:
- 6 hearths
- internal diameter: 3,5 / 5 m
- compact furnace with insulated steel casing
• Annual production  25 000 / 75 000 tpy (wet - oily)
• Availability > 95 %
• Sludge rating  3~10 t/h (wet)
• Lime charging capacity  0,1~1,5 t/h (5-15%)
• Output:  “iron oxide”
• Residual oil content < 0,1%
© Paul Wurth 2010
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PLD PROCESS : Industrial plant typical design
• Costs:
- Range of total investments: 8~12 mio€
- Range of operating costs: 20~40 €/t oily sludge
• Credits:
- Value of output: 70~85 €/t iron oxide
- Dumping cost avoided: ~70 €/t oily sludge
- Transport cost avoided: ~10€/t oily sludge
© Paul Wurth 2010
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PLD PROCESS : Process profitability for 75ktpy PLD plant (EXAMPLE)
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CONCLUSIONS
 By-products recycling becomes a priority for
industrials
 “Zero waste” technologies will be a key point
for the sustainability of metallurgical
operations in the near future
© Paul Wurth 2010
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THANK YOU FOR YOUR ATTENTION
© Paul Wurth 2010
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