The technique holds promise for a warming world. Since carbon dioxide can be turned into minerals, scientists say humans could use that process to sequester greenhouse gases underground and prevent them from hanging out in the atmosphere, where they fuel global warming and climate change.
It involves dissolving carbon dioxide in water and placing it in contact with rocks, where it transforms into a mineral.
Although the technique shows promise, the rocks present a dilemma of their own. The process of mineralization can make rocks less permeable and limit the amount of carbon they store.
The research involved dunite, a coarse, dense type of igneous rock named after a mountain in New Zealand. Since it’s common on land and in the ocean, and since it naturally sucks up carbon and turns it into minerals, it’s a good candidate for carbon capture.
Previous research suggests that dunite powder could one day be spread on croplands in a variety of geographic regions and be used to mitigate climate change in places such as India and Brazil.
When the scientists soaked dunite in carbonized water, the minerals created reduced the rocks’ permeability at first. But then, cracks formed in the rocks as the minerals sought new space within them.
The results were “pretty amazing,” Catalina Sanchez-Roa, a climate fellow at Columbia University in New York, told Eos. “It’s the first time that we have seen the cracking happening in experiments.”
The technique has a long way to go before it’s seen as viable. But the research is a new step along that cracked path.
H14C-05 — Permeability evolution during carbon mineralization in peridotite: implications for geological carbon storage