To avoid dangerous climate change, new technologies must remove billions of tonnes of CO2 from the atmosphere every year by mid-century. Here we detail a land-based enhanced weathering cycle utilizing magnesite (MgCO3) feedstock to repeatedly capture CO2 from the atmosphere. In this process, MgCO3 is calcined, producing caustic magnesia (MgO) and high-purity CO2. This MgO is spread over land to carbonate for a year by reacting with atmospheric CO2. 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 tCO2−1 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 GtCO2 year−1, and may make a meaningful contribution to mitigating climate change.
CITATION STYLE
McQueen, N., Kelemen, P., Dipple, G., Renforth, P., & Wilcox, J. (2020). Ambient weathering of magnesium oxide for CO2 removal from air. Nature Communications, 11(1). https://doi.org/10.1038/s41467-020-16510-3
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