Scientists at the University of Oxford demonstrate how it is possible to directly extract valuable metals from hot salty fluids ('brines') trapped in porous rocks at depths of around 2km below dormant volcanoes. They propose this radical green-mining approach to provide essential metals for a net zero future—copper, gold, zinc, silver and lithium—in a sustainable way.
Magma beneath volcanoes releases gasses that rise towards the surface. These gasses are rich in metals. As the pressure drops, the gasses separate into steam and brine. Most metals dissolved in the original magmatic gas become concentrated in the dense brine, which in turn gets trapped in porous rock. The less dense, and metal-depleted steam continues up to the surface, where it can form fumaroles, such as those seen at many active volcanoes.
In a new paper, published today in Open Science, Oxford scientists, based at the Department of Earth Sciences, reveal how this trapped, subterranean brine is a potential 'liquid ore' containing a slew of valuable metals, including gold, copper and lithium, that could be exploited by extracting the fluids to the surface via deep wells.
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