Rockit – the geochemistry of turning carbon to rock via geological CO2 storage in basalts (Flexible Funding 2022)

Dr Amir Jahanbakhsh at Heriot-Watt University was awarded funding in the UKCCSRC’s Flexible Funding 2022 call to look at the “Rockit – the geochemistry of turning carbon to rock via geological CO2 storage in basalts”.

The focus of my project was on in-situ carbon mineralisation. Basalt, one of the most prevalent types of extrusive igneous rocks found on Earth’s surface, has erupted in massive quantities over geological periods due to volcanic activity. Basaltic rocks are notably abundant in divalent cations like Ca2+, Mg2+, and Fe2+, which exhibit high reactivity when exposed to CO2-rich fluids. Consequently, they hold significant potential for capturing and storing CO2 by facilitating the formation of stable carbonate minerals such as calcite (CaCO3), magnesite (MgCO3), and siderite (FeCO3). Usually, CO2 and water are injected together in basalt formations, inducing a rapid chemical reaction for storing CO2 in carbonized form.

Although basalts have shown promising potential for secure and permanent storage (removal) of CO2, there are still research questions around the geochemical reactions’ timescale, effective parameters and the whole process optimization. We performed a series of CO2–brine-basalt interaction experiments at high-pressure and high-temperature conditions resembling storage conditions. We investigated the effect of grain size, pressure, salinity and basalt rock type on the process of CO2 carbonation.

This work was a collaboration between the Research Centre for Carbon Solutions (RCCS) at Heriot-Watt University and the School of Geosciences at the University of Edinburgh. This was the second collaborative work between the two teams on projects addressing one of the unprecedented challenges of the century. As a result of this collaboration, we have been successful in harnessing our expertise across disciplines and organisations, exchanging and sharing knowledge, and integrating geochemistry with the engineering approach in order to investigate the uncertainties in the performance of basaltic rock for carbon storage purposes. This project helped me to build a close collaboration with research fellows at the University of Edinburgh and, hopefully, this is a good start for a long-term collaboration.

As a researcher who has been mainly focusing on modelling and application of numerical simulations to investigate scientific problems, this funding opportunity provided me to expand my experience into the experimental world. Understanding the challenges and limitations behind designing and collecting experimental data which potentially should be used for validation of any modelling or simulation work has been a great experience which has happened throughout this project.

I would like to thank all my funders – UKCCSRC, RCCS, and IDRIC – for supporting me throughout this project.

Read more on Amir’s Flexible Funding 2022 project page.