Researchers have succeeded in artificially producing the mineral magnesite that can absorb CO2 from the atmosphere.
Magnesite’s carbon-storing capacity was already known to scientists. But the process normally takes thousands of years. By reducing this to a matter of days, the technique could become a valuable approach to carbon capture and storage (CCS).
Every ton of magnesite is capable of removing around half a ton of CO2 from the atmosphere.
“This is a process which takes hundreds to thousands of years in nature at Earth’s surface,” explained Professor Ian Power, who led the new research at Trent University.
To overcome this issue, Professor Power and his team identified the processes that form magnesite naturally at low temperatures, and then used this knowledge to dramatically accelerate its crystallisation.
Using polystyrene microspheres as a catalyst to speed up the reactions that form this rock, they reduced its creation time to 72 days. The whole process takes place at room temperature, making it extremely energy efficient.
These results were presented by the scientists at the Goldschmidt geochemistry conference in Boston.
“For now, we recognise that this is an experimental process, and will need to be scaled up before we can be sure that magnesite can be used in carbon sequestration (taking CO2 from the atmosphere and permanently storing it as magnesite),” said Professor Power.
“This depends on several variables, including the price of carbon and the refinement of the sequestration technology, but we now know that the science makes it doable”.
CCS technologies feature prominently in many plans to reach the targets set by the international Paris climate agreement and avert catastrophic climate change.
However, some prominent scientists have described the expectations placed on them as “seriously over-optimistic” considering the lack of industry-ready procedures.
“It is really exciting that this group has worked out the mechanism of natural magnesite crystallisation at low temperatures, as has been previously observed – but not explained – in weathering of ultramafic [magnesium-rich and low silica] rocks,” said Professor Peter Kelemen, a carbon capture expert at Columbia University.
“The potential for accelerating the process is also important, potentially offering a benign and relatively inexpensive route to carbon storage, and perhaps even direct CO2 removal from air.”