SADOWAY TARGET METAL

Consider titanium

Titanium. There isn’t another metal with such great overall properties–toughness and specific strength, light weight, exceptional corrosion resistance, and performance even at extreme temperatures.

Ti

Titanium 22

Guggenheim Museum, Bilbao, Spain

Designed by architect Frank Gehry and clad in titanium

POWERING CRITICAL MINERAL SUPPLY CHAINS

Comparison: Titanium processes

THE KROLL PROCESS

Metals are found in nature as minerals, i.e., metal compounds. Titanium, for example, occurs as rutile, which is titanium dioxide and as ilmenite, which is iron titanate. Titanium metal is traditionally produced by the Kroll Process, a chemical reaction of titanium tetrachloride with magnesium. The titanium product is termed metal sponge which must be melted to remove entrained salt. Titanium tetrachloride is prepared by carbochlorination of rutile, a process that produces toxic dioxin as a byproduct. The tetrachloride is subjected to multiple distillation steps to rid the feedstock of impurities. Such a facility comes with high CapEx, runs with high OpEx and generates high levels of pollutants.  

The process of turning rutile or ilmenite into titanium is fundamentally difficult and the many steps involved in the Kroll process adds to the cost. The Kroll process for titanium has changed little since the 1950s. There is a better way.

The Kroll faces these challenges:

  • Huge facility spanning large area

  • Long permitting time

  • High labor intensity

  • Batch process with long cycle time (~12 hours)

  • Yield discrete batches-not continuous flow

  • High level of impurities

  • Tremendous energy cost

  • High carbon intensity

  • Huge waste

THE SADOWAY PROCESS

Consider a process in which titanium dioxide is dissolved in a solvent composed of a solution of other metal oxides into which are immersed two electrodes. By the action of electric current the titanium dioxide is decomposed into liquid titanium which pools on the bottom of the cell and into oxygen which vents through the top of the cell. No Kroll reactor, no carbochlorinator, no vacuum arc remelting furnace.

In one step we move from dirt to liquid metal of requisite purity, and at or below the market price point. One-pot smelting. Processing compression.

High-temperature electrochemistry is a platform technology that can be adapted for processing other ores and converting them into their respective metals, e.g., titanium, antimony, scandium, beryllium, vanadium, and rare earths (neodymium and samarium).

The processing compression in Sadoway High-Temperature Electrolysis significantly reduces the number of steps with attendant savings in CapEx and OpEx—power, CO2 emissions, footprint-- as well as labor, equipment, transportation, permitting time, and related expenses. . 

  • Two buildings: extractory and refinery.

  • Each building holds  10x10x10’ cells in 2x2 rows.

  • Yield continuous flow which translated into exceptioinally high space-time yield

  • Zero to no waste or emissions

Comparison: Kroll process v. Sadoway process

One metric tonne output of titanium

Smelter land requirement

75 acres

Kroll process

Sadoway process

1 acre

Kroll process requires over 75 acres per one tonne annual output. Sadoway process requires ~1 acre per one tonne annual output.

CO2 emissions

28 tonnes

Kroll process

Sadoway process

.919 tonnes

C02 emissions per one metric tonne output of titanium.

Kroll process produces 28 tonnes or 28,000 Kg. Sadoway process produces 0.919 tonnes or 919 Kg.

Power cost

Kroll process

Sadoway process

$40

$3,585

Cost for power--assumes .05¢ KWh or $50 MWh.

PROOF OF CONCEPT

Titanium experiments carried out at MIT and 22Ti

An image of titanium pooled on the bottom of the crucible

Work performed in 1999 by Prof. Sadoway at MIT and the titanium start up 22Ti, is evidence of conversion of rutile into liquid titanium by molten beryllate electrolysis.

Experimental conditions

Melt- BeO 42%(mol), CaO 28%(mol), TiO2 30%(mol)

Cathode – Mo rod

Anode- Carbon rod

Electrolysis carried out at 1700℃ in a Mo crucible. A constant current of 10A was passed through the cell over 4-hr period.  Cell voltage remained between ~0.9-1.1V throughout the run.

 Observations

Silver colored deposit was observed in the bottom of crucible.

Analysis

Crucible surface and the melt were analyzed by EDX and XRD. Both methods indicated the presence of liquid Titanium.

SEM-EDX analysis of the bottom

WHY IS THIS IMPORTANT?

Producing titanium without the Kroll process saves cost of power, smelter, labor, and time.

In one step, we moved from dirt to liquid metal of requisite purity, well below below the market price point. One-pot smelting without CO2 emissions and the by-product dioxins.