Queen's University

Enhancing natural reactions to capture and store carbon

Image of carbon mineralization products: a Mg-carbonate mineral, nesquehonite, replaces a Mg-rich primary mineral, brucite. Image has been false-coloured.The reduction of CO2 emissions from human activities is urgently required to avoid the most harmful effects of climate change. Engineered strategies that can capture CO2 from the air or industrial waste gases and store it securely away from the atmosphere are required to limit global surface temperature increases. Over geologic time, natural mineral weathering reactions have acted to control CO2 concentrations in the atmosphere; the dissolution of atmospheric CO2 in rain and pore waters drives mineral weathering. Dissolved carbon is then transported to the oceans, where it can precipitate as carbonate minerals, like calcite and aragonite, that store carbon in solid form over geologic timescales. If accelerated over natural weathering rates, this process can be used to help offset the CO2 emissions from human activities. This process is referred to as carbon mineralization, as the CO2 is converted to mineral form.

Through my research, I investigate methods to accelerate carbon mineralization in Mg-rich rock and industrial waste materials. The fine-grained rock waste that is generated during mining operations for ores such as nickel, chromite, and diamond, are particularly well-suited to capture carbon. I investigate the mechanisms that control these mineral weathering reactions in laboratory settings and develop numerical models, known as reactive transport models, that can help better design accelerated carbon storage strategies. This research also studies the processes that control CO2-driven mineral weathering in natural environments, and how changes in climate and/or CO2 concentration in the atmosphere over millennia may have altered CO2 storage and mineral weathering rates over geologic time.