Optimized, zero waste pyrometallurgical processing of … · 2019-01-07 · ISA - IOM Workshop, Warsaw, Sept 3-5, 2018 Optimized, zero waste pyrometallurgical processing of polymetallic

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)


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)


Clarion Clipperton Zone - License Areas

© BGR© BGR

© BGR


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


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


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


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


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


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


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


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



Nodules

Nodule Smelting EAF

Mn Reduction EAF

Flux, Coke


Flux,Coke

FeMn(Si)



Air/O2

Flux

Alloy Converter

NiCuCoMo(Fe)Alloy

FeO•SiO2 toMn-Reduction 2. Smelting step



SlagMetal

Addition of flux and resulting liquidus temperature



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



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. -%)



Nodules

Nodule Smelting EAF

Mn Reduction EAF

Flux, Coke


Flux,Coke

FeMn(Si)



Air/O2

Flux

Alloy Converter

NiCuCoMo(Fe)Alloy

FeO•SiO2 toMn-Reduction


Experimental Results – Final Mineral Product

XRF analyses, RWTH Achen, Sommmerfeld, 2018

Heavy metal content of the final mineral product (wt. -%)


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


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

http://www.ime-aachen.de/

http://www.ime-aachen.de/

Documents

Optimized, zero waste pyrometallurgical processing of … · 2019-01-07 · ISA - IOM Workshop, Warsaw, Sept 3-5, 2018 Optimized, zero waste pyrometallurgical processing of polymetallic