School of Mining Engineering

Resource Processing in Space

Seher Ata1, Ghislain Bournival1 and Michael Manfield2, 1The School of Mining Engineering, University of New South Wales, Sydney, Australia 2School of Biotechnology and Biomolecular Sciences,, University of New South Wales,

Sydney, Australia

Overview to extraterrestrial minerals

Astreoids Nickel, iron ore, rare earth minerlals, gold, PGM, diamond, carbon, cobalt Lunar Pyroxene (augite and pigeonite) Fe,Mg,Ca silicate Plagiocl ase (anorthite) Ca, Al silicate 0livine Fe, Mg silicate Ilmenite Fe, Mg silicate Casiterite Fe, Ti Oxide Mars Magnesium, aluminium, titanium, iron, chromium lithium, cobalt, nickel, copper, zinc, niobium, molybdenum, lanthanum, europium, tungsten, gold

Processing of extraterrestrial materials

Processing methods are more likely: • Derived from terrestrial operations and adapted to the

extraterrestrial environment. • Processes of extraterrestrial materials are likely be significantly

different than their terrestrial counterparts largely because of major differences in the environment.

Challenges for extraterrestrial materials processing

• Absence of atmosphere • Lack of readily accessible working fluids (air, oil water) • Low gravity • High ultraviolet radiation • Broad temperature fluctuations • Low pressure

Terrestrial Mineral Processing

Physical separation (optical, density, electrical conductivity, magnetic properties, surface chemistry) Hydrometallurgy & Biomining Pyromethallurgy

Terrestrial Mineral Processing

Possible methods for extraterrestrial materials processing: Magnetic Separation

Separates minerals according to their magnetic properties. All minerals will have one of three magnetic properties • diamagnetic: weakly repelled by magnetic

field; • paramagnetic : weakly attracted by magnetic

field • ferromagnetic : highly susceptible and

involves greater forces.

Process can be applied dry - desirable method for the beneficiation of extraterrestrial material.

Successful studies 0n magnetic separation of lunar soils.

Possible methods for extraterrestrial materials processing: Electrostatic separation

Utilises the differences in electrical conductivity between minerals in the ore. Relative conductors separated from relative non- conductors

Generally used to separate small grains (~75-250µm)-already liberated granular mixtures

Requires completely dry environment-Main disadvantage of the method on earth. What about in space?

Wills, B.A., Finch, J.A., 2016. Wills' mineral processing technology: An introduction to the practical aspects of ore treatment and mineral recovery. 8th edn., Elsevier

Possible methods for extraterrestrial materials processing: Froth flotation

Particles are in water Separation based on the

interfacial properties of the mineral

Hydrophobic particles are selectively to air bubbles

Wills, B.A., Finch, J.A., 2016. Wills' mineral processing technology: An introduction to the practical aspects of ore treatment and mineral recovery. 8th edn., Elsevier.

Froth Flotation-Density separation

The reality is flotation is a density separation process

Hydrophobic particles attach to air bubbles

The density of the air-particle aggregate is lower than the density of the medium

The loaded bubbles rise to the surface where they are collected

Foaming in microgravity

Bubble rise velocity mostly determined by density difference

Opportunity for coarse particle flotation

Speed process kinetics through device modification e.g. centrifugal force

Caps, at al. 2014. Does water foam exist in microgravity? Europhysics News, 45(3), 22-25.

The impossible made possible

Limited foam drainage (which is caused by the gravitational force)

Wet foams Water can be foamed!

Caps et al. 2014. Does water foam exist in microgravity? Europhysics News, 45(3), 22-25.

Pros Cons

Versatile Coarse particles (low

gravitational force) Limited oxidation of naturally

hydrophobic minerals

Low reagent usage?

Water & gas requirement Slow separation (density based) Limited understanding of wet

foams (entrainment?)

Flotation in space

Biomining: Can microbes play a role in resource extraction in space?

Microorganisms are the most pervasive form of life on Earth (5x1030 cells ~ upto 1 billion per teaspoon soil)

There are over 100 known bacterial phyla with an extraordinary array of metabolic capabilities

Minerals can be used as electron donors and acceptors in microbial respiration

The appeal of biological approaches to mineral extraction are low costs, low maintenance, low energy and minimal equipment requirements

e-

Electron Acceptor (Eg. Sulfate)

Electron Donor (Eg. Ferrous Iron)

e-

Biomining: Can microbes play a role in resource extraction in space?

Bacteria and archaea tolerate extreme heat and cold (oceanic thermal vents, hot springs and arctic).

Can they be active in space with rates useful for resource acquisition?

Most microorganisms on Earth live in biofilms state. Biofilms consist of cells enmeshed in a polymeric matrix attached to a surface

The biofilm state protect the cells against predators If microorganisms are to be active in space, then this is likely to occur within

biofilms.

Biomining: Can microbes play a role in resource extraction in space?

Biomining is used to produce copper, gold, cobalt, nickel, zinc, and uranium. Globally 15-20% Cu and 5% Au produced by this method In copper bioleaching, microorganisms gain energy from ferrous iron and

sulphur oxidation and produce ferric iron and sulphuric acid which in turns chemically solublises copper

These oxidative processes are oxygen dependent and therefore limited in the space environment

Reductive bioprocesses have more promise in space An example :Reduction of iron in nickel ores to release nickel. No requirement for oxygen.

Biomining: Can microbes play a role in resource extraction in space?

Strategies for biomining in space Repeated inocilation (with mineral salts, water, poymer) of a large

number of asteroids Monitor remotely for microbial activity over extended time periods

(decade, centuries) Harvest when ripe

Conclusions

Space environment is significantly different from the environment on Earth - extraction techniques will not operate without significant changes

Dry processes (electrostatic, magnetic separation) has relatively higher chance to be employed for space materials processing- Flotation?

Biomining - reductive bioprocesses have more promise in space

Froth flotation- Density separation

The reality is flotation is a density separation process

Hydrophobic particles attach to air bubbles

The density of the air-particle aggregate is lower than the density of the medium

The loaded bubbles rise to the surface where they are collected

Fundamental of froth flotation

• Particles are in water • Separation based on the

interfacial properties of the mineral

• Selective attachment of hydrophobic particles to air bubbles

Wills, B.A., Finch, J.A., 2016. Wills' mineral processing technology: An introduction to the practical aspects of ore treatment and mineral recovery. 8th edn., Elsevier, 498 p.

Density separation

• The reality is flotation is a density separation process

• Hydrophobic particles attach to air bubbles

• The density of the air-particle aggregate is lower than the density of the medium

• The loaded bubbles rise to the surface where they are collected

Foaming in microgravity

• Bubble rise velocity mostly determined by density difference

• Opportunity for coarse particle flotation

• Speed process kinetics through device modification e.g. centrifugal force

Caps, H., Delon, G., Vandewalle, N., Guillermic, R.M., Biance, A.L., Saulnier, L., Yazhgur, P., Rio, E., Salonen, A., Langevin, D. 2014. Does water foam exist in microgravity? Europhysics News, 45(3), 22-25.

The impossible made possible

• Limited foam drainage (which is caused by the gravitational force)

• Wet foams • Water can be foamed!

Caps, H., Delon, G., Vandewalle, N., Guillermic, R.M., Biance, A.L., Saulnier, L., Yazhgur, P., Rio, E., Salonen, A., Langevin, D. 2014. Does water foam exist in microgravity? Europhysics News, 45(3), 22-25.

Flotation in space

Pros • Versatile • Coarse particles (low

gravitational force) • Limited oxidation of naturally

hydrophobic minerals • Low reagent usage?

Cons • Water requirement • Gas requirement • Slow separation (density based) • Limited understanding of wet

foams (entrainment?)