Ilmenite Reduction

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Lunar Ilmenite reduced at 1050°C for 3 hrs

Reduction of ilmenite (FeTiO₃) is a chemical reaction proposed for use in production of oxygen (LUNOX) from lunar resources.

Hydrogen Reduction

Hydrogen reduction is one method currently being tested by many Universities. Products of the hydrogen reduction are free iron, titanium dioxide, and water. The resulting water can be removed by condensation and separated via electrolysis to produce oxygen and H₂ (hydrogen). The hydrogen is then be recycled into the reaction.

The basic process sequence is to separate ilmenite from lunar soil, crush it to a fine powder to maximize the surface area, heat the ilmenite in an enclosed reaction vessel in the presence of hydrogen gas, condense the steam which is produced by the reaction, and then use electrolysis to separate the water into hydrogen and oxygen. The process is best utilized if the plant is sited in a location in which ilmenite composes a high fraction of the soil.

The reaction sequence is:

Reduction:
FeTiO₃+H₂ ---->Fe+TiO₂+H₂O
Electrolysis:
2H₂O ---->2 H₂+ O₂
Net Reaction:
2FeTiO₃---->2Fe+2TiO₂+ O₂

Carbothermal Reduction

Oxygen can be retrieved from Ilmenite (FeTiO₃) and Rutile (TiO₂) by means of carbothermal reduction. In experiments, powdered carbon and powdered ilmenite were evenly mixed and then heated to 1500 degrees Celsius. The end products of this reaction are Oxygen and a high strength Ceramic-metal composite (Cermet) of Iron (Fe) and Titanium Carbide (TiC) which has high chemical stability. The amount of reinforcing TiC ceramic in the matrix can be controlled via the amount of rutile and carbon used and will be demonstrated shortly by a stoichiometric equation. While this method provides a means of retrieving all of the oxygen from ilmenite/rutile and a potential of producing reinforced, high performance, high wear components and cutting tools from lunar regolith, it is at the cost of highly valuable carbon needed for biological processes. The process will also require the separation of ilmenite/rutile from regolith by some means.

Stoichiometry for this reaction:

FeTiO₃ + nTiO₂ + (4+3n)C ---->Fe + (1+n)TiC + (3+2n)CO
Where n=the quantity of additional TiO₂ molecules