The mineral olivine can extract CO₂ from the atmosphere and store it in stabile carbonate minerals

The mineral olivine is mainly found as part of the rock peridotite, which constitutes 80% of the Earth’s volume. Olivine is mostly found deep within the Earth but is pushed to the Earth’s surface by tectonic processes. Weathering of olivine caused by interaction with the wind and water results in the olivine breaking down and releasing magnesium to the water, which can then react with atmospheric CO₂ to form a stable magnesium- and CO₂ rich mineral called magnesite. The formation of magnesite therefore captures and store, or ‘lock’, the CO₂ in the structure of minerals and this chemical process consequently removes CO₂ from the atmosphere. 

Can solve the current climate crisis

Observations from Oman show that 1000 kg of olivine can capture up towards 600 kg CO₂ from air, and if you could add just one weight percent of CO₂ (relative to the mass of peridotite) to the peridotite found in Oman, you could solve the current climate crisis. Thus, theoretically, one could solve the climate crisis purely by using this mineral to capture and store excess atmospheric CO₂. The question is whether this theoretical scenario can be implemented on a large scale, whether the processes controlling weathering of olivine can be optimized for industrial use, and whether the weathering reaction timescale is fast enough to meet our needs.

In this project, we work on recreating the natural process in which CO₂ is extracted from the atmosphere by reaction with olivine. To do this, we run experiments in the laboratory where we let olivine react with CO₂ and water at various temperatures and CO₂ concentrations.

These experiments allow us to study the natural weathering process of olivine and gives us the opportunity to evaluate the potential for use of such processes in the Danish industry. If we can identify the optimal conditions for when olivine dissolves and magnesite is formed, and adapt these to match the industrial environment, such as conditions found in the chimneys from powerplants, we could potentially stop the emission of CO₂ from such plants without affecting the power production. Olivine is therefore an important tool to potentially contribute to the solution and mitigation of our climate crisis in the future. 

Olivine has an enormous potential to extract CO₂ from the atmosphere. It is basically so unstable at the temperatures and the pressure we experience at the Earth’s surface, so it quickly triggers a chemical reaction which forms CO₂-rich minerals

We are a 100 percent sure, that CO₂ from the atmosphere can be captured during the weathering of olivine and formation of carbonate minerals, especially since the process already occurs in the nature. But we must find a way to optimise this process and learn whether this process can be implemented on an industrial scale.

The potential of using geological processes and materials to capture excess atmospheric CO₂ is huge and there is something beautiful in the fact, that the nature is offering us solutions to save itself from the mistakes of humans. We just have to find the right key to the solution.

Contact

Maja Bar Rasmussen
mr@ign.ku.dk
+45 35 32 88 87

Participants in the project

Maja Bar Rasmussen
Postdoc, IGN

Kristoffer Szilas
Lektor, IGN

Peter Kelemen
Professor, Columbia University

The project is financed by

Project period: 2021 til 2024