Scientists at the University of Adelaide are fine-tuning a solvent extraction process that could help make asteroid mining economically viable.

The technique relies upon continuous-flow chemistry, where tailored combinations of solvents are mixed with asteroid material to harvest the precious metals contained within. According to the researchers, the process is scalable and can operate in zero gravity and vacuum conditions. Its capabilities are currently being trialled in-orbit following a May 4 launch coordinated in partnership with US firm Space Tango.

“Continuous-flow chemistry is proven technology,” said Professor Volker Hessel, deputy dean of research at the University of Adelaide’s Faculty of Engineering, Computer & Mathematical Sciences (ECMS) and Professor in the School of Chemical Engineering. “The process extracts metal by mixing and separating solvents. Successive passes of the chemicals through the process results in complete extraction of the metals.”

“Asteroid-born metals co-exist in different combinations and concentrations from those found in terrestrial rock, so one of the challenges that the team has is understanding how these may be successfully extracted. This new disruptive technology is needed as traditional technology does not provide the solution.

“Continuous-flow chemistry technology must be perfected to use as little water as possible. While launching costs are projected to fall in the mid-term, they will remain a serious point to consider. Instead of needing hundreds of tonnes of water to extract one tonne of metal, development of the technology may mean that less than 10 tonnes are required.”

Mining the asteroid wealth of our solar system is an enticing proposition that has long attracted the attention of both governments and private companies. It remains largely in the realm of science fiction, however, with launch costs and technical hurdles so far proving insurmountable. But with potentially trillions of dollars of resources contained within these rocky celestial bodies, asteroid mining is proving to be an irresistible goal.

“In the same way that colonialists and explorers exploited the resources of the New World about 400 years ago, today’s pioneering asteroid miners are reaching out to exploit riches in space,” said Professor Hessel. “There are 17 missions currently underway for space resource exploitation. The NASA OSIRIS-Rex mission to Bennu asteroid will return with samples in 2023.

“Asteroids such as Bennu are closer to us than Adelaide is to Alice Springs about 1000 kilometres away in Earth’s near orbit. Advances in space exploration mean that these bodies which contain nickel, cobalt, and platinum as well as water and organic matter, are now within reach.”

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