Ambient weathering of magnesium oxide for CO<sub>2</sub> removal from air.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32620820.
- Also identified by DOI 10.1038/s41467-020-16510-3 and PMC identifier 7335196.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
To avoid dangerous climate change, new technologies must remove billions of tonnes of CO<sub>2</sub> from the atmosphere every year by mid-century. Here we detail a land-based enhanced weathering cycle utilizing magnesite (MgCO<sub>3</sub>) feedstock to repeatedly capture CO<sub>2</sub> from the atmosphere. In this process, MgCO<sub>3</sub> is calcined, producing caustic magnesia (MgO) and high-purity CO<sub>2</sub>. This MgO is spread over land to carbonate for a year by reacting with atmospheric CO<sub>2</sub>. 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<sub>2</sub><sup>-1</sup> 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<sub>2</sub> year<sup>-1</sup>, and may make a meaningful contribution to mitigating climate change.