Optimized, zero waste pyrometallurgical processing of … · 2019-01-07 · ISA - IOM Workshop,...
Transcript of Optimized, zero waste pyrometallurgical processing of … · 2019-01-07 · ISA - IOM Workshop,...
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Optimized, zero waste pyrometallurgicalprocessing of polymetallic nodules from
the German CCZ license area
David Friedmann, Marcus Sommerfeld, Bernd Friedrich (RWTH Aachen), Thomas Kuhn, Carsten Rühlemann (BGR)
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Polymetallic nodule chemistry
Mn Ni Cu Co Mo V Fe Si Al Mg Ca Zn
Wt.-% 31 1.4 1.2 0.16 0.06 0.06 6.2 5.9 2.3 1.9 1.6 0.15
Average chemical composition of nodules of the German territory:
Manganese CopperVery fine, indistinct mineral particles (<< 1 µm) Beneficiation of e.g. a NiCu-concentrate is unsuccessful
Iron
Minerals are complex manganese and iron oxides and hydroxides (e.g. Buserite, Todorokite, Manganite or Goethite)
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Clarion Clipperton Zone - License Areas
© BGR© BGR
© BGR
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Hydrometallurgical processing – bottom line
Large amounts of waste products and wastewater
Production of Manganese product uneconomical
Intensive consumption of chemicals Costly solution treatment through
precipitation, pH adjustment etc. Complex multi-stage organic Solvent-
Extraction (SX) necessary Low throughputs
Energy intensive drying (mainly)redundant
Generation of „pure“ metals (Ni, Cu,Co) possible via electrolysis
Limited CO2 emissions compared topyrometallurgy
Advantages: Disadvantages:
Nickel © Thyssen Copper © Aurubis Red mud landfill © GreenPeace Laboratory-SX
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Simplified process developed in the 1970s by INCO
Nodules
Nodule Smelting EAF
Coke
MnO•SiO2•FeO Discard Slag
FeMnNiCuCoAlloy
Mn ~10 wt%
Air/S2
Flux
Alloy & Matte Converter
NiCuCo(Fe)Sulfides
FeO•SiO2•MnODiscard Slag
HydrometallurgicalProcessing
(HP-Leaching, SX, EW)
Ni
Cu
Co
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Key Aspects for a Successful Zero-Waste Concept
Additional Goals:• Complete use of Mn-bearing material stream
• Metal-recovery rates > 95%
• Recycling of flue dusts
• Slag design for high metal recovery and
usable final slag
Main Goal:Separation of valuable metal stream (Ni, Cu, Co, Mo; 2.5 – 3 wt%) fromMn-stream (> 30 wt%) early in the process
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Simplified process for direct nodule smelting
Nodules
Nodule Smelting EAF
Mn Reduction EAF
Flux, Coke
MnO•SiO2•FeOSlag (75-85%)
Flux,Coke
FeMn(Si)
CaO•SiO2Mineral Product
FeNiCuCoAlloy (6-10%)Mn < 5 wt%
Air/O2
Flux
Alloy Converter
NiCuCoMo(Fe)Alloy
FeO•SiO2 toMn-Reduction
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
1200
1300
1400
1500
1600
1700
1800
1900
2000
0% 5% 10% 15% 20% 25% 30%
T liq
[°C
]
Flux Addition [wt%]
<SiO2> <CaO> <Al2O3> <MgO> <Fe2O3> <TiO2><Borax><SiO2-CaO>
Slag Design and FactSage™ ModelsMetallurgical challenges:
Comparison MnO contents: BGR: > 45 wt% INCO: 30 wt%
Significantly higher liquidus temperature of autogenic slag
> 1500 °C: Mn reduction thermodynamically significant
1263°C 1204°C
Lowest reachable liquidus with a maximum of 30 wt% flux addition
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Experimental Setup – Lab-scale SAF at IME
Transformer-rectifier
TIT01
TIT02
Graphite electrode
Lining(Al2O3 & Cr2O3)
Insulation(Al2O3)
Water cooled copper electrode
Power supply: 3 - 100 kW DC Up to 6 L melt volume Optionally with graphite crucible insert
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Experimental Results – 1. Smelting Step
0
20
40
60
80
100
Co Cu Fe Mn Mo Ni
Phas
e dis
trib
utio
n in
wt%
Slag
Metal
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Experimental Results – 1. Nodule Smelting Step
0
20
40
60
80
100
0
20
40
60
80
100
No fluxing 15 % SiO2 25 % SiO2 30 % SiO2-CaO
20 % SiO2-TiO2, 10 %
Al2O3
25 % TiO2 20 %Na2B4O7
20 %Fe2O3
Effic
ienc
e of
slag
ging
ope
ratio
n in
%
Reco
very
rate
in %
Co Cu Fe Mo Ni MnO
Nofluxing
15%SiO2
25%SiO2
30%SiO2-CaO
20%SiO2-TiO2,10 % Al2O3
20%TiO2
20%Na2B4O7
20%Fe2O3
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Simplified process for direct nodule smelting
Nodules
Nodule Smelting EAF
Mn Reduction EAF
Flux, Coke
MnO•SiO2•FeOSlag (75-85%)
Flux,Coke
FeMn(Si)
CaO•SiO2Mineral Product
FeNiCuCoAlloy (6-10%)Mn < 5 wt%
Air/O2
Flux
Alloy Converter
NiCuCoMo(Fe)Alloy
FeO•SiO2 toMn-Reduction 2. Smelting step
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Experimental Results – 2. Smelting Step
SlagMetal
Addition of flux and resulting liquidus temperature
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Experimental Results – 2. Smelting Step
MnO
CaO SiO2
1: Monoxide2: a-Ca2SiO43: Mn2O3(s2)4: Olivine5: Rhodonite6: Wollastonite7: SiO2(s4)8: SiO2(s6)9: Slag-liq#210: CaSiO3(s2)11: Ca3Si2O7(s)
1 2
3
4 5
6 7
89
810
11
w (CaO)
→ CaO-additionReduction after fluxing by:
→ 5 wt% CaO
→ 15 wt% CaO
→ 30 wt% CaO
T in °C1800
1700
1600
1500
1400
1300
1200
1100
Modelled with FactSageTM
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Experimental Results – 2. Smelting Step
Ferromangan (carburé, high-C):DIN 17564
Wt.-%
Mn: 75 – 80
C: 6.0 – 8.0
P: 0 – 0.25
Si: 0 – 1.0
Ti: 0 – 0.20
V: 0 – 0.20
Cu: 0 – 0,013
XRF analyses, RWTH Achen, Sommmerfeld, 2018
Element content of ferromanganese (wt. -%)
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Simplified process for direct nodule smelting
Nodules
Nodule Smelting EAF
Mn Reduction EAF
Flux, Coke
MnO•SiO2•FeOSlag (75-85%)
Flux,Coke
FeMn(Si)
CaO•SiO2Mineral Product
FeNiCuCoAlloy (6-10%)Mn < 5 wt%
Air/O2
Flux
Alloy Converter
NiCuCoMo(Fe)Alloy
FeO•SiO2 toMn-Reduction
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Experimental Results – Final Mineral Product
XRF analyses, RWTH Achen, Sommmerfeld, 2018
Heavy metal content of the final mineral product (wt. -%)
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
Summary• SiO2 flux of 10-15 wt% is sufficient to reach < 5 wt% Mn in Fe Metal
• SiO2-CaO and Na2B4O7 also show good results
• Metal-recovery rates > 95% for Ni, Co, Mo
• Mn-slag is suitable for FeMn production (Basicity adjustment required)
• >75 wt% Mn in metal, Si, Ti, Cu in some cases too high
• Final calcium-silicate slag is almost heavy metal free
Outlook• Further look at Cu-reduction in first melting step
Kinetics
• Scale-up of entire process necessary
Summary
ISA - IOM Workshop, Warsaw, Sept 3-5, 2018
IME Process Metallurgy and Metal Recycling RWTH Aachen University
Prof. Dr.-Ing. Dr. h.c. Bernd Friedrichwww.ime-aachen.de
Thank you for your attention!
Federal Institute for Geosciencesand Natural Resources (BGR)Dr. Thomas Kuhnwww.bgr.bund.de