Introduction

This technical review is an update of a 2005 IEAGHG review of mineralisation as means of CO2 sequestration, which concluded “Significant breakthroughs are needed but obstacles to be overcome are considerable”. This review confirms that view and concludes that recent research initiatives are unlikely to lead to technically and economically viable CO2 sequestration processes.

Summary

An insurmountable barrier is the scale of mineral handling that would be required for CO2 absorption by a mineral at a coal-fired power station. The amount of igneous mineral material to be mined, processed and returned to the ground would involve materials handling at an order of magnitude greater scale than the scale of the coal mining operation that provided the fuel that is burned to produce the CO2. That would result in significant environmental consequences and life-cycle energy demands.

Natural carbonation of minerals is a very slow process that would need to be greatly accelerated to provide a useful industrial process. The recent research initiatives have focussed on complex processes, involving staged conversion at high temperature and high pressure and conditions. Catalysis also requires acidic conditions. Technically attractive concepts have not yet been defined, so these ideas have not advanced to the stage of requiring assessment of economic viability.

An alternative mineralisation concept is the spreading of alkaline minerals on the ground for the purpose of drawing down CO2 from the atmosphere via enhanced mineralisation. This review has identified that there is a wide divergence of views on the optimum particle size for material to perform that function. This geo-engineering approach to addressing climate change is probably limited to situations where there is a beneficial side-effect of infrastructure projects.

In summary, no technology breakthroughs have been identified in this review of mineralisation concepts.