Carbon mineralization and geological storage of CO₂ in basalt: Mechanisms and technical challenges

Climate change is taking place due to significant emissions of greenhouse gases into the atmosphere. CO₂ storage in geological formations is a promising approach that can help to reduce greenhouse gas emissions from large emitters such as the steel and cement industries. However, effective storage in underground formations requires active trapping mechanisms to reduce the likelihood of leakage. Carbon mineralization is a trapping technique that can permanently store CO₂ in reactive rocks such as basalt. Although this method has been known for a long time, only two pilot projects in Iceland and the USA practiced CO₂ injection into basalts. This could be mainly due to the complexity of the interactions, the rapid carbon mineralization, and the difficulty to estimate the storage capacity in the long term. In this paper, we discuss different mechanisms and technical challenges of CO₂ storage in igneous rocks and propose a selection criterion based on laboratory and field-scale experience. It appears that basalt is a suitable rock for rapid carbon mineralization given its worldwide distribution, vesicular texture, and favourable mineral composition, but the lack of effective monitoring techniques and the amount of water required for injection are two major challenges that need to be addressed.