Carbon dioxide removal materials: Integrated capture and permanent sequestration
Team: Matthew Kanan, Kate Maher, Jonathan Fan, Lynette Cegelski
Level 2: Developing
The Earth has vast reserves of rocks that could be used to remove CO2 from air and sequester it permanently in the form of carbonates. Rocks composed of magnesium-rich silicates (“ultramafic rocks”) have the potential to remove more than 100 trillion tons of CO2, far more than humans have emitted throughout history. The mining industry already produces hundreds of millions of tons of ultramafic waste each year, which could increase substantially with the expansion of mining in the coming decades. Ultramafic rocks interact with CO2 to form carbonates naturally, but the rate under ambient conditions is negligible. The key technical obstacle to removing CO2 with ultramafic rocks at scale is to increase their rate of CO2 uptake while minimizing energy demand and cost.
This project will exploit a recently discovered thermal reaction between a calcium source and an ultramafic input to generate materials that remove CO2 at useful rates. This reaction transforms rocks and mining waste into reactive alkaline solids that form carbonates in ambient air in weeks to months, or within minutes in more concentrated sources. To advance toward impact at scale, this project will design and validate the process technology for generating the alkaline materials, optimize their rate of CO2 uptake under application-relevant conditions, and establish and strengthen the external partnerships needed for commercialization.