Mineralisation of CO2 using serpentinite rock - Towards industrial application

In Finland one (and maybe the only) option for large-scale CO2 capture, utilisation and storage (CCUS) seems to be mineralisation, also known as mineral carbonation. Mineral resources in the country should allow for the fixation of quite a few Gt CO2. The process route that is currently being developed towards industrial application involves the production of reactive magnesium in the form of Mg(OH)2 from serpentinite rock material followed by conversion into MgCO3 using a pressurised fluidised bed (PFB) reactor. Iron, present in the serpentinite rock material is released during the Mg(OH)2 production. Although the rate of carbonation of Mg(OH)2 particles is satisfying, the final level of conversion to MgCO3 must yet be brought closer to 100%. The carbonation chemistry competes with undesirable calcination of Mg(OH)2 to less reactive MgO. As for the Mg(OH)2 production, the best result obtained so far is 80%. In this paper our recent results obtained with this CO2 mineral carbonation process route are summarised. Progress on the scale-up and application of the process route at an industrial demonstration scale are addressed, with process heat integration and the operation on flue gases directly (without a CO2 pre-separation step!) being key features for economic viability.