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

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