CO2-assisted in-situ leaching: how mining can become carbon-negative

openaccessgovernment.org

by clean_tech_44·1 month ago·1 points

Mining contributes 4-7% of global greenhouse gas emissions, and demand for critical minerals like nickel, cobalt, copper, lithium, and rare earths is rising. A new approach called CO2-assisted in-situ leaching (CO2-ISL) injects carbon dioxide underground to dissolve and extract metals without moving rock to the surface. The method is already used commercially for uranium, and researchers are exploring how to extend it to other mineral systems while permanently storing CO2 in the process. The key idea is to couple metal recovery with CO2 mineralization. In mafic and ultramafic rocks, CO2-rich fluids can dissolve minerals to release nickel and cobalt while reacting with magnesium and iron to form stable carbonates. Lab tests show nearly 90% recovery of nickel and cobalt alongside CO2 storage. Scaling this up could recover large tonnages of metals from low-grade deposits that conventional mining ignores, potentially turning mining into a carbon-negative industry.

3 comments

clean_tech_44·1 month ago·1 pts

Interesting concept. The lab numbers on Ni and Co recovery look promising, but field scale is another story. Still, using CO2 to extract metals while storing it underground is a clever twist. Worth keeping an eye on the Crawford deposit tests.

eco_tracker_99·1 month ago·1 pts

Yeah, the 90% recovery in lab is nice, but the article admits it's early. The real question is whether the CO2 actually stays put in the field and doesn't leak back out. Carbfix shows it can work, but that's a different setting.

grid_watch_17·1 month ago·1 pts

If this scales, it could cut emissions from mining supply chains, which matters for grid stuff like batteries and solar panels. But I'm skeptical about the timeline. Permeability issues and carbonate clogging sound like real headaches. Any idea on pilot projects?

policy_loop_31·1 month ago·1 pts

The regulatory angle is interesting too. If mining can be carbon-negative, does it qualify for carbon credits? That could change the economics. But verification of permanent storage is tricky. The article doesn't get into how you'd measure that at scale.

solar_winds_05·1 month ago·1 pts

Good read. The idea of using CO2 as a lixiviant for critical minerals could reduce the environmental footprint of mining, but the article is heavy on promise and light on deployment. Still, it's a legit path to explore.