electrochemical pathways towards carbon-free … · sadoway gcep carbon management in manufacturing...
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ELECTROCHEMICAL PATHWAYS
TOWARDS
CARBON-FREE
METALS PRODUCTION
Department of Materials Science
& Engineering
Massachusetts Institute of Technology
Cambridge, Massachusetts
Donald R. Sadoway
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
The message
The road to sustainability is paved
with advanced materials.
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
problems with metals extraction
� steelmaking makes CO2 �
2 FeO + C = 2 Fe + CO2
(� kg C / kg Fe) x 1.2 billion tonnes
� sundry HAPs including Mn & Pb,
polycyclic organics, benzene, & CS2
� unfavorable by-products �
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
Why is metal production so dirty?
� many processes are over
100 years old
� attitude then of indifference
towards the environment
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
Why is metal production so dirty?
“Where there’s smoke, there’s money.”
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
We’re all just temporarily visiting this planet
Towards sustainability
� Green technology
ELECTROCHEMICAL PATHWAYS
TOWARDS
CARBON-FREE
METALS PRODUCTION
Department of Materials Science
& Engineering
Massachusetts Institute of Technology
Cambridge, Massachusetts
Donald R. Sadoway
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
Where do metals come from?
� occur naturally as compounds
� beneficiated � high-purity feed
� reducing agents: H, C, M, e-
� options for sustainability?
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
beyond the blast furnace
extreme form of molten salt electrolysis
� molten oxide electrolysis:
where pure oxygen gas is the by-product
�����
� most metals are found in nature as oxides
� “like dissolves like”
� e- is the best reducing agent
world capacity: ~40 million tons/year
aluminum produced by electrolytic reduction of Al2O3
decompose Al2O3 dissolved in Na3AlF6 (T = 960°C)
� liquid Al (-) and CO2 (+)
� find an inert anode & molten oxide electrolyte
Charles Martin Hall, USAPaul Héroult, France
1886
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
(FeOx) � Fe(l) + � O2
iron
iron
green ironmaking: cell schematic
x
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
Technology Needs: dateline 2050
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
Technology Taxonomy: Reducing Agents
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
Environmental Impact & Energy Savings
kg
CO
2/t
ls
GJ n
et
en
erg
y
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
Environmental Impact & Energy Savings
� CO2 emissions reduced from 1750 kg/tonne liquid steel
for benchmark blast furnace technology
to 345 kg/tonne liquid steel: a five-fold reduction
� 90 g CO2/kWh for generation of electric power
� equivalent energy consumption: MOE vs benchmark
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
Other Benefits
tonnage oxygen
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
scientific and technical challenges
� molten oxides of transition metals exhibit
electronic conduction
� inert anode operable at temperatures as
high as 1700°C in an oxide melt
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
some of the relevant engineering science:
� electrical conductivity measurements
� transference number measurements
� voltammetry � process kinetics
� electrolysis testing
�
�
�
�
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
conductivity measurements
� inventing two new techniques for aggressive
melts at high temperatures:
� moveable coaxial cylinders
� 4-point crucible
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
moveable coaxial cylinders
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
effect of FeO addition: � = �(T, c)
-2.5
-2.0
-1.5
-1.0
-0.5
0
50 52 54 56 58 60 62
105/T (K)
S1
20%
5%
10%
15%
1.000
0.606
0.367
0.223
0.135
0.082
1727 1650 1579 1513 1451 1394 1340
T(ºC)
� /
S c
m-1
ln �
/ S
cm
-1
1425
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
FeO greatly raises conductivity
0
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18
� / S
cm
-1
T = 1425ºC
XFeO in S1
� = 2.0766 XFeO + 0.0897
R2 = 0.9796
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
regression of conductivity data
y = x
R2 = 0.8918
0
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.10 0.20 0.30 0.40 0.50
� = - 0.138 - 0.361*SiO2 + 1.186*FeO + 0.917*(FeO+MgO+CaO)
� / S
cm
-1
T = 1425ºC
0
� = � ai*X
i
electrochemistry at white heat
CaO - MgO - SiO2
T = 1575°C
scan rate = 50 mV s-1
electrochemistry at white heat
CaO - MgO - SiO2
T = 1575°C
scan rate = 50 mV s-1
--- supporting electrolyte
--- 5 wt% FeO
add 5% FeO to
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
electrolytic production of molten iron:
cathode: Mo
anode: Pt
electrolyte:
CaO - MgO - SiO2
feed: FeO
crucible: Mo
reactor tube: Al2O3
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
constant-current electrolysis at 1575oC
current density: ~1 A cm-2
iron
electrolyte
Mo crucible
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
more electrolytic production of molten iron:
iron
SEM and EDX analysis
oxygen generation on the moon
by molten oxide electrolysis:
� sustaining human life
� rocket propellant
let’s now raise our sights
Oxygen Extraction From Regolith
University of Michigan April 4, 2008 Sadoway
Lab-scale Cell for Regolith Electrolysis
water chiller (for cell cap)
Ar in
Ar out
potentiostat and
impedance spectrometer
furnace power supply
hot zone
Ar bubblers
University of Michigan April 4, 2008 Sadoway
Lab-scale Cell for Regolith Electrolysis
water chiller (for cell cap)
Ar in
Ar out
potentiostat and
impedance spectrometer
furnace power supply
hot zone
Ar bubblers
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
University of Michigan April 4, 2008 Sadoway
University of Michigan April 4, 2008 Sadoway
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
O2 evolution rate vs. optical basicity
i = FAk°CO2-e-�F�/RT
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
O2 evolution rate vs. optical basicity
i = FAk°�e-�F�/RT
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
cyclic voltammetry in titanates at 1550ºC
WE: Mo
RE: Ti
CE: Mo
supporting electrolyte
melt containing TiO2
WE: Ti
RE: Ti
CE: Mo
cyclic voltammetry in titanates at 1550ºC
supporting electrolyte
melt containing TiO2
Cu
rre
nt
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
electrolytic production of liquid titanium
frozen electrolyte
titanium puddle
Mo crucible
cathode: Mo
anode: C
current density �1 A/cm2
T = 1725°C (above m.p. of Ti)
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
analysis of metal pool indicates titanium
CP titaniumtitanium
made by theSadowayProcess
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
what have we learned?
� deposition of Fe, Ti, Ni, & Cr in oxide melts
from oxide feedstock
� very high current densities are sustainable
� 5 A cm-2 observed; maybe higher!
c.f. 0.7 A cm-2 in Hall-Héroult cell
� 15� productivity of aluminum smelting
� capable of tonnage productivity
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
what else have we learned?
� first evidence of inert anode
� carbon-free metal making with tonnage
industrial oxygen as by-product
� full realization of the concept of
molten oxide electrolysis
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
workshop questions
� How would low- or zero-cost CO2
sequestration change the game, and
what barriers to separating and capturing
carbon would remain?
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
workshop questions
� If carbon-free or carbon-neutral energy
carriers were cost competitive with
current feedstocks, what technical and
economic challenges would prevent the
switch to those fuels?
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
workshop questions
� What are the opportunities for disparate
industries to collaborate on carbon
management?
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
workshop questions
� How can industry's specialized
knowledge of process engineering and
material handling address the grand
challenge of reducing carbon emissions?
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
workshop questions
� What are the research priorities in your
area of investigation and why?
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
workshop questions
� What barriers exist to successful
research and what breakthroughs are
needed?
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
workshop questions
What are the opportunities for
fundamental, academic research to
develop pathways for technologies to
overcome the barriers?
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
workshop questions
Where do you feel that a contribution by
a project such as GCEP could have the
most impact?
GCEP Carbon Management in Manufacturing Industries April 15, 2008 Sadoway
towards carbon-free metallurgy
The End