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Transcript of Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium...
![Page 1: Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium Extraction by Molten Oxide Electrolysis Naomi A. Fried and Donald R. Sadoway Department](https://reader031.fdocuments.net/reader031/viewer/2022020315/5ad942c67f8b9ab8378e71ab/html5/thumbnails/1.jpg)
Titanium Extraction by Molten Oxide Electrolysis
Naomi A. Fried and Donald R. Sadoway
Department of Materials Science & EngineeringMassachusetts Institute of Technology
Cambridge, Massachusetts
![Page 2: Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium Extraction by Molten Oxide Electrolysis Naomi A. Fried and Donald R. Sadoway Department](https://reader031.fdocuments.net/reader031/viewer/2022020315/5ad942c67f8b9ab8378e71ab/html5/thumbnails/2.jpg)
Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
the need for new technology
many unit operations
problems with Ti extraction today:
high capital costshigh operating costs
environmental liabilities
C & Cl in presence of Odioxins? furans?
![Page 3: Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium Extraction by Molten Oxide Electrolysis Naomi A. Fried and Donald R. Sadoway Department](https://reader031.fdocuments.net/reader031/viewer/2022020315/5ad942c67f8b9ab8378e71ab/html5/thumbnails/3.jpg)
Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
Titanium extraction: the front end
O2O2
TiCl4
O2
TiCl4
![Page 4: Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium Extraction by Molten Oxide Electrolysis Naomi A. Fried and Donald R. Sadoway Department](https://reader031.fdocuments.net/reader031/viewer/2022020315/5ad942c67f8b9ab8378e71ab/html5/thumbnails/4.jpg)
Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
Titanium extraction: Kroll reduction
Cl2
MgCl2
TiCl4TiCl4
MgCl2
Cl2
![Page 5: Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium Extraction by Molten Oxide Electrolysis Naomi A. Fried and Donald R. Sadoway Department](https://reader031.fdocuments.net/reader031/viewer/2022020315/5ad942c67f8b9ab8378e71ab/html5/thumbnails/5.jpg)
Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
a technological response?
extreme form of molten salt electrolysis
molten oxide electrolysis:
where pure oxygen gas is by-product
most metals are found in nature as oxides
“like dissolves like”
![Page 6: Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium Extraction by Molten Oxide Electrolysis Naomi A. Fried and Donald R. Sadoway Department](https://reader031.fdocuments.net/reader031/viewer/2022020315/5ad942c67f8b9ab8378e71ab/html5/thumbnails/6.jpg)
Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
schematic of prototype cell
TiO2 Ti + O2
Green metallurgy: processes emitting
only products
![Page 7: Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium Extraction by Molten Oxide Electrolysis Naomi A. Fried and Donald R. Sadoway Department](https://reader031.fdocuments.net/reader031/viewer/2022020315/5ad942c67f8b9ab8378e71ab/html5/thumbnails/7.jpg)
Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
Molten oxide electrolysis: the front end
TiO2
O2
TiCl4
TiO2
O2
“Bayer-like”
![Page 8: Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium Extraction by Molten Oxide Electrolysis Naomi A. Fried and Donald R. Sadoway Department](https://reader031.fdocuments.net/reader031/viewer/2022020315/5ad942c67f8b9ab8378e71ab/html5/thumbnails/8.jpg)
Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
Molten oxide electrolysis:
O2 by-product high purity TiO2
Molten Oxide Electrolysis
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Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
feasibility assessment: issues
molten titanates reportedly exhibit electronic conduction
inert anode operable at 1700ºC
![Page 10: Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium Extraction by Molten Oxide Electrolysis Naomi A. Fried and Donald R. Sadoway Department](https://reader031.fdocuments.net/reader031/viewer/2022020315/5ad942c67f8b9ab8378e71ab/html5/thumbnails/10.jpg)
Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
feasibility assessment: current study
electrical conductivity measurements
transference number measurements
modeling electrical properties
applicability to titanium production
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Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
conductivity measurements
inventing two new techniques for aggressive melts at high temperatures:
moveable coaxial cylinders
4-point crucible
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Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
experimental apparatus
conductivity measurements:- impedance spectroscopy- varying immersions or
varying interelectrode gapisolate melt resistance
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Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
all-metal, coaxial-cylinder electrode
(does not contact liquid)enabling high-accuracy conductivity measurements in the most chemically aggressive melts
Mo
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Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
moveable coaxial cylinders
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Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
TiO2 – BaO phase diagram
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Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
tailoring electrical properties
73% TiO2
67% TiO2
67% TiO2
73% TiO2
73% TiO2solid phase present
73% TiO2solid phase present
tran
sfer
ence
num
ber
telectronic
tionic
4.00
3.98
3.96
3.94
3.92
3.90
67% TiO2
73% TiO2
elec
tric
al c
ondu
ctiv
ity (
S/cm
)
ln(σ•T) = 9.867 - 1778/T
ln(σ•T) = 9.896 - 1836/T73% TiO2
67% TiO2
67% TiO2
73% TiO2
73% TiO2solid phase present
73% TiO2solid phase present
tran
sfer
ence
num
ber
telectronic
tionic
4.00
3.98
3.96
3.94
3.92
3.90
67% TiO2
73% TiO2
elec
tric
al c
ondu
ctiv
ity (
S/cm
)
ln(σ•T) = 9.867 - 1778/T
ln(σ•T) = 9.896 - 1836/T
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Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
transference number measurements
- stepped-potential chronoamperometry with impedance correction
isolate electronic and ionic components of conductivity
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Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
stepped-potential chronoamperometry
potential step = 80 mVinitial current peak of 1.62 A
decaying to 1.27 Ainitial relaxation peak of −0.30 A
decaying to −0.02 A
TiO2–BaO (73 mol% TiO2) T=1400°C
potential step = 80 mVinitial current peak of 1.62 A
decaying to 1.27 Ainitial relaxation peak of −0.30 A
decaying to −0.02 A
TiO2–BaO (73 mol% TiO2) T=1400°C
potential step = 80 mVinitial current peak of 1.62 A
decaying to 1.27 Ainitial relaxation peak of −0.30 A
decaying to −0.02 A
TiO2–BaO (73 mol% TiO2) T=1400°C
![Page 19: Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium Extraction by Molten Oxide Electrolysis Naomi A. Fried and Donald R. Sadoway Department](https://reader031.fdocuments.net/reader031/viewer/2022020315/5ad942c67f8b9ab8378e71ab/html5/thumbnails/19.jpg)
Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
tailoring electrical properties
73% TiO2
67% TiO2
67% TiO2
73% TiO2
73% TiO2solid phase present
73% TiO2solid phase present
tran
sfer
ence
num
ber
telectronic
tionic
73% TiO2
67% TiO2
67% TiO2
73% TiO2
73% TiO2solid phase present
73% TiO2solid phase present
tran
sfer
ence
num
ber
telectronic
tionic
73% TiO2
67% TiO2
67% TiO2
73% TiO2
73% TiO2solid phase present
73% TiO2solid phase present
tran
sfer
ence
num
ber
telectronic
tionic
![Page 20: Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium Extraction by Molten Oxide Electrolysis Naomi A. Fried and Donald R. Sadoway Department](https://reader031.fdocuments.net/reader031/viewer/2022020315/5ad942c67f8b9ab8378e71ab/html5/thumbnails/20.jpg)
Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
electrowinning experiments
galvanostatic electrolysis at 1450°C
(-) Cu( ) | TiO2 – BaO – MgO | Pt (+)
electrolytic generation of oxygen gas confirmed
![Page 21: Titanium Extraction by Molten Oxide Electrolysisweb.mit.edu/dsadoway/www/MOE_Ti.pdf · Titanium Extraction by Molten Oxide Electrolysis Naomi A. Fried and Donald R. Sadoway Department](https://reader031.fdocuments.net/reader031/viewer/2022020315/5ad942c67f8b9ab8378e71ab/html5/thumbnails/21.jpg)
Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
next steps
electrolysis in a fully idealized cell:
(-) C | TiO2 – BaO | Pt (+)
electrolysis in a cell w/ idealized anode:
(-) M( ) | TiO2 – BaO | Pt (+)
selection and testing of anode materials
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Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
lunar colonization: NASA
oxygen for human life support and rocket propellant
lunar regolith is a multicomponent silicate rich in iron and titanium.
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Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
… in closing
high-accuracy electrical conductivity and transference number measurements in molten oxides at extreme temperatures
electrolytic production of liquid titanium not unviable
implications for fluxes and slags,e.g., welding, refining, &
metallothermic reduction
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Sadoway, MIT TMS Meeting, Charlotte, NC March 15, 2004
acknowledgment