Ambient weathering of magnesium oxide for CO2 removal from air

Abstract

Abstract To avoid dangerous climate change, new technologies must remove billions of tonnes of CO 2 from the atmosphere every year by mid-century. Here we detail a land-based enhanced weathering cycle utilizing magnesite (MgCO 3 ) feedstock to repeatedly capture CO 2 from the atmosphere. In this process, MgCO 3 is calcined, producing caustic magnesia (MgO) and high-purity CO 2 . This MgO is spread over land to carbonate for a year by reacting with atmospheric CO 2 . The carbonate minerals are then recollected and re-calcined. The reproduced MgO is spread over land to carbonate again. We show this process could cost approximately $46–159 tCO 2 −1 net removed from the atmosphere, considering grid and solar electricity without post-processing costs. This technology may achieve lower costs than projections for more extensively engineered Direct Air Capture methods. It has the scalable potential to remove at least 2–3 GtCO 2 year −1 , and may make a meaningful contribution to mitigating climate change.

Abstract of "Ambient weathering of magnesium oxide for CO2 removal from air" by Noah McQueen, P. B. Kelemen, Gregory M. Dipple et al., https://doi.org/10.1038/s41467-020-16510-3, used under its Creative Commons Attribution license (CC-BY); markup removed, otherwise unmodified.