In June, researchers in Iceland made the announcement that they had found a way to turn carbon dioxide into stone. The team captured CO2 emitted by a nearby geothermal plant, and inject it into basalt rock, along with water. The gas mineralized into calcium carbonate, the main constituent of limestone.
This process of turning gas into a solid gets around the downfalls of sequestration, which include CO2 leaking into the air or groundwater. The project, called CarbFix, isnt a fast fix-all: it uses more water in the process than many sites can process. The research is promising for it’s success, however, as many other promising sequestration efforts have been plagued with problems.
A separate team was expected to announce a similar finding in 2016, but had managed to do so with out water. Todd Schaef, geochemist at the Pacific Northwest National Laboratory, says the team’s goal was to bring CO2 to a ‘supercritical’ state, increasing the pressure and temperature before injecting it into basalt. Once supercritical, carbon dioxide has the properties of both a liquid and a gas, letting it undergo a chemical reaction with basalt, turning it into stone.
“In an operation that produces a lot of wastewater…the CarbFix method will make perfect sense. But where you don’t have that wastewater, perhaps you’d want to go with our approach” – Todd Schaef
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