Titanium Electrowinning Process Case Western Reserve University (PI: Rohan Akolkar)

August 24 – 25, 2016 Detroit, MI

METALS Annual Meeting

sponge

Proposed Ti C Electrowinning electrolysis Cl2 + TiO2 CO2 + TiCl4 Process Cl2 Outline

‣ Team Intro ‣ Technical Concept ‣ Technical Progress to date ‣ TEA Highlights ‣ Future Goals ‣ Q&A

1 Case Western Reserve University

‣ Case Western Reserve University Team Members: PI: Rohan Akolkar Personnel: 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 Proposed Electrowinning Cell Design Segmented Diaphragm Design Enables Ti Electrowinning __ +

Catholyte Anolyte sponge

Proposed Ti C Electrowinning electrolysis Cl2 + TiO2 CO2 + TiCl4 Process Cl2

! Ti Electrowinning Cl2 Evolution!

2 Technical Concept

PROBLEM STATEMENT PROPOSED SOLUTION Use a stack of thin diaphragms

e POWER TiCl4 Stack of thin SUPPLY – diaphragms + __ +

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TiCl4 Ensures diaphragm & cell stability Design Rule: Δϕ = il'/κ < ΔE Increases electrowinning efficiency Problem with diaphragm-less cell: Design Rule: Δϕ = il'/κ < ΔE Redox shuttling of titanium ions causes low current efficiency Ensures diaphragm & cell stability Increases electrowinning efficiency Technical Progress (Phase-I)

Molten-salt electrowinning reactor Ti sponge was deposited, was constructed and operated isolated and then characterized

6 100

5 Thin diaphragms enabled 80 4 stable cell voltage at 60 3 industrial plating rates 40 2 n>3 diaphragms provide

1 20 efficient Ti electrowinning Cell Voltage (V) Cell Voltage

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Process Efficiency ProcessEfficiency (%) 0 0 100 200 300 400 500 600 0 1 2 3 4 5 Time (min.) Number of Diaphragms (n) Technical Progress (Phase-II)

~100 mg Ti deposits were collected and analyzed for purity using EDS

Molten-salt electrowinning reactor Titanium was relocated inside a glove-box for )

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controlled environment studies w

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EDS analysis shows up o

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r contamination in the P Oxygen electrowon Ti deposits 1 2 3 4 5 (5%) Experiment Number TEA Highlights

Metal

Ore TiO2 Ti C CO2 Electrolysis TiCl4

Cl2 Cl2

Metric ARPA-E METALS Proposed Technology GOALS (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) 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.

Q2 2016 Basic feasibility of Ti electrowinning demonstrated )

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oxygen contamination via distillation a

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Detailed TEA for Ti powder electrowinning underway – C r

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Seeking additional federal and/or industrial funding for T

A 2017 developing a Ti powder production process ( QUESTIONS?

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