Titanium Electrowinning ProcessCase Western Reserve University (PI: Rohan Akolkar)
August 24 – 25, 2016
Detroit, MI
METALS Annual Meeting
Proposed
Electrowinning
ProcessCl2 TiO2 + CO2 TiCl4 +
Ti
Cl2
electrolysis
sponge
C
Outline
‣ Team Intro
‣ Technical Concept
‣ Technical Progress to date
‣ TEA Highlights
‣ Future Goals
‣ Q&A
1
Case Western Reserve University
2
Proposed
Electrowinning
Process
Proposed Electrowinning
Cell Design
Cl2 TiO2 + CO2 TiCl4 +
Ti
Cl2
electrolysis
sponge
C
__ +
Catholyte Anolyte
Segmented Diaphragm Design
Enables Ti Electrowinning
Ti Electrowinning! Cl2 Evolution!
‣ Case Western Reserve University Team Members:
PI: Rohan AkolkarPersonnel: Dai Shen, Stephen Banik, Mirko Antloga, Craig Virnelson,
Uziel Landau, Mark DeGuire, David Zeng
‣ Goals of the ARPA-E METALS Project:
– To develop a novel electrowinning process for low-cost extraction of titanium metal from ore, and
– Demonstrate stable, energy-efficient extraction of high-purity Ti powder
Technical Concept
POWER SUPPLY
e
__ +
CA
TH
OD
E AN
OD
E
Ti+4
TiCl4
Ti+2
‘Redox Shuttling’
Problem with diaphragm-less cell:
Redox shuttling of titanium ions causes
low current efficiency
PROBLEM STATEMENT PROPOSED SOLUTIONUse a stack of thin diaphragms
– +
l'l'l'
Stack of thin
diaphragms
Tita
niu
m E
lectr
ow
inn
ing
Ch
lori
ne
Evo
lutio
n
ΔE
ΔE
ΔE
Design Rule: Δϕ = il'/κ < ΔE
Δϕ
Δϕ
TiCl4
(LiCl+KCl
eutectic salt mixture)
Ensures diaphragm & cell stability
Increases electrowinning efficiency
Design Rule: Δϕ = il'/κ < ΔE
Ensures diaphragm & cell stability
Increases electrowinning efficiency
Technical Progress (Phase-I)
Molten-salt electrowinning reactor
was constructed and operated
Ti sponge was deposited,
isolated and then characterized
0
1
2
3
4
5
6
0 100 200 300 400 500 600
Time (min.)
Cell V
olt
ag
e (
V) Thin diaphragms enabled
stable cell voltage at
industrial plating rates
0
20
40
60
80
100
0 1 2 3 4 5
Pro
cess E
ffic
ien
cy (
%)
Number of Diaphragms (n)
n>3 diaphragms provide
efficient Ti electrowinning
Technical Progress (Phase-II)
Molten-salt electrowinning reactor
was relocated inside a glove-box for
controlled environment studies
Experiment Number
Pro
du
ct
Co
mp
osit
ion
(w
t.%
)
Titanium (95%)
Oxygen (5%)1 2 3 4 5
~100 mg Ti deposits were collected
and analyzed for purity using EDS
EDS analysis shows up
to 5 wt.% oxygen
contamination in the
electrowon Ti deposits
TEA Highlights
Metric ARPA-E METALS
GOALS
Proposed Technology
(Ti Electrowinning)
Cost of Ti Sponge < $4 / kg $4-5 / kg
Energy Consumption < 35 kWhr / kg 25-30 kWhr / kg
CO2 emissions < 11 kg-CO2 / kg 12-15 kg-CO2 / kg
‣ Cost reduction primarily driven by energy-efficiency and process
simplicity (elimination of the sacrificial Mg recycling as needed in
conventional Kroll process)
Cl2
TiO2
TiCl4
C ElectrolysisTi
Cl2
CO2
Metal
Ore
Future Goals
‣ Purity improvements:
– Currently, oxygen contamination of Ti product is a technology risk. To
address this risk, we are designing an efficient vacuum distillation unit to
purify the Ti product with the goal of achieving >99% purity.
Basic feasibility of Ti electrowinning demonstratedQ2 2016
Immediate focus is on improving Ti purity by lowering
oxygen contamination via distillationQ3-Q4 2016
Q3-Q4 2016
2017
Detailed TEA for Ti powder electrowinning underway –
will likely pivot process towards powder (vs. sponge)
Seeking additional federal and/or industrial funding for
developing a Ti powder production process
Ind
ustr
y C
oll
ab
ora
tor:
AT
I (A
TI
in k
ind
su
pp
ort
: p
ers
on
ne
l, a
na
lyti
cs
, T
EA
)
QUESTIONS?
8