from the Economist
A paper just published in Science offers a possible solution (to climate change). By burying CO2 in the right sort of rock, a team of alchemists led by Juerg Matter, a geologist at Southampton University, in Britain, was able to transmute it into stone. Specifically, the researchers turned it into carbonate minerals such as calcite and magnesite. Since these minerals are stable, the carbon they contain should stay locked away indefinitely.
They collected 175 tonnes of it, mixed it with a mildly radioactive tracker chemical, dissolved the
mixture in water and pumped it into a layer of basalt half a kilometre below the surface. They then kept an eye on what was happening via a series of monitoring wells. In the event, it took a bit less than two years for 95% of the injected CO2 to be mineralised.
They followed this success by burying unscrubbed exhaust gas. After a few teething troubles, that worked too. The H2S reacted with iron in the basalt to make pyrites, so if exhaust gas were sequestered routinely, scrubbing might not be needed. This was enough to persuade Reykjavik Energy, the power station’s owners, to run a larger test that is going on at the moment and is burying nearly 10,000 tonnes of CO2 and around 7,300 tonnes of H2S.
from Science (June 2016 issue):
Inject, baby, inject! H. Jesse Smith Science 6/10/16
Atmospheric CO2 can be sequestered by injecting it into basaltic rocks, providing a potentially valuable way to undo some of the damage done by fossil fuel burning. Matter et al. injected CO2 into wells in Iceland that pass through basaltic lavas and hyaloclastites at depths between 400 and 800 m. Most of the injected CO2 was mineralized in less than 2 years. Carbonate minerals are stable, so this approach should avoid the risk of carbon leakage.