Titanium Extraction & Molten Salt Lab
Model solid-state electrochemical deoxygenation of titanium dioxide (FFC Cambridge process) in molten CaCl2 vs Kroll thermal reduction, aerospace alloy economics, and 20-year project finance.
Cell & Metallurgical Parameters
Levelized Cost of Titanium (LCOT) Breakdown
| Cost Element | Unit Cost ($/kg Ti) | Annual Spend ($M) | Share of LCOT |
|---|
Sensitivity Matrix: Power Tariff vs Rutile Feedstock (Net LCOT $/kg)
Matrix maps sensitivity of Net LCOT ($/kg Ti) across varying clean electricity tariffs ($/MWh) and synthetic rutile ore costs ($/tonne TiO2). Green cells indicate highly cost-advantaged smelting economics below $14.00/kg.
Chemical Metallurgy & Molten Salt Electrochemistry
Titanium is an irreplaceable structural metal across commercial aerospace (fuselage frames, landing gear, engine turbofans), naval defense, chemical processing, and surgical implants due to its extraordinary strength-to-weight ratio, high temperature creep resistance, and impervious corrosion passivity. However, historical commercial production has been shackled to the 1940s-era Kroll process—an environmentally punishing, multi-day batch metallurgical process.
1. Direct Solid-State Electrochemical Deoxygenation (FFC Cambridge Process)
Discovered at the University of Cambridge by Derek Fray, Tom Farthing, and George Chen, the FFC Cambridge process performs direct cathodic electrochemical deoxygenation on solid metal oxides without melting the metal. Compacted, porous pellets of titanium dioxide ($\text{TiO}_2$) serve as the solid cathode immersed in a bath of molten calcium chloride ($\text{CaCl}_2$) at 850°C to 900°C.
When a DC potential (2.8 to 3.2 V) below the decomposition potential of $\text{CaCl}_2$ is applied, electrons transfer from the cathode into the solid oxide lattice, driving oxygen ions ($\text{O}^{2-}$) out of the solid phase and into the molten salt solution:
The reduction proceeds sequentially through lower titanium suboxide phases:
At the anode, oxygen ions discharge. When using non-consumable inert cermet anodes (e.g. calcium ruthenate or nickel ferrite alloys), pure oxygen gas is evolved:
2. The Traditional Kroll Process Benchmark
The conventional Kroll process involves hazardous carbochlorination of rutile with petroleum coke at 1,000°C to generate volatile liquid titanium tetrachloride ($\text{TiCl}_4$):
Purified $\text{TiCl}_4$ is then transferred into sealed steel retorts containing molten magnesium at 850°C, where it reacts over several days: $\text{TiCl}_4 + 2\text{Mg} \to \text{Ti} + 2\text{MgCl}_2$. High-vacuum distillation at 1,000°C is required to separate the sponge from $\text{MgCl}_2$, and the $\text{MgCl}_2$ must be electrolyzed back to magnesium metal and chlorine. This circular batch loop consumes 38 to 48 kWh/kg Ti and generates 16 to 22 kg $\text{CO}_2$/kg Ti.
3. Direct Additive Manufacturing Powder Economics
Because the FFC Cambridge reduction is a topotactic solid-state reaction, the metal retains the microscopic particle morphology of the original oxide precursor. By preparing spherical $\text{TiO}_2$ micro-pellets via spray drying, the electrolytic cell directly outputs spherical titanium or pre-alloyed Ti-6Al-4V powder suitable for powder bed fusion (PBF) and directed energy deposition (DED) 3D printing. This bypasses multiple vacuum arc remelting (VAR) ingot melts and plasma atomization, dropping additive powder costs from >\$100/kg to under \$35/kg.