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