Peter McGrail of the Pacific Northwest National Laboratory, a branch of the Department of Energy, and his colleagues were also working on storing carbon dioxide in basalts, based upon small scale laboratory experiments showing the gas does bind with the rock. And they, like the Carbfix project, were ready to scale up and perform an actual injection, in this case 1253 meters deep into basalts from the Columbia River region of Washington State.
In their results reported Friday in the journal Environmental Science & Technology Letters, they go beyond the Carbfix project in several key ways, McGrail said. First, they injected carbon dioxide in its fluid, supercritical form, which is most likely to be how it is received and transported from industrial projects. And second, after two years had passed, they took core samples of the rocks, using a battery of tests to prove definitively that the CO2 had indeed turned into a carbonate rock called ankerite, comprised of calcium, carbon, oxygen, iron, magnesium, and manganese.
This was a key demonstration because there are some carbonates that occur naturally in basalts, and so it was important to distinguish the new rock from what had already been there.
B. Peter McGrail*†, Herbert T. Schaef, Frank A. Spane, John B. Cliff, Odeta Qafoku, Jake A. Horner, Christopher J. Thompson, Antoinette T. Owen, and Charlotte E. Sullivan