Going one step further, another team was expected to announce in late 2016 that it had found a way to mineralize carbon dioxide — without adding any water. Todd Schaef, a geochemist at the Pacific Northwest National Laboratory, says the team’s solution brings the gas to a “supercritical state,” increasing the temperature and pressure before injecting it into basalt rock. Once supercritical, carbon dioxide has properties of both gas and liquid, allowing it to undergo a chemical reaction with the basalt, turning CO2 into stone.
“In an operation that produces a lot of wastewater,” Schaef says, “the CarbFix method will make perfect sense. But where you don’t have that wastewater, perhaps you’d want to go with our approach.”