Catalyzed Carbon Mineralization Integrated to Capture – CARMIN

Climate emergency related to greenhouse gas emissions calls for the development of large-scale solutions for the capture, storage and use of CO2. Direct aqueous carbonation of magnesium or calcium silicates, widely abundant in the rocks that make up the earth's mantle and in the waste products from the mining industry, constitutes a very promising way to this end by leading to the formation of stable products that can be used in the construction sector (silica and carbonates) for a circular economy. However, it requires accelerating the kinetics of mineral leaching, which is the limiting step, and separating the other metals present that may be undesirable or valuable elsewhere. The CARMIN project proposes to hybridize two solutions for the activation of the carbonation of these phases, currently studied by members of the consortium: a chemical activation using the catalytic effect of molecular complexes based on amino acids, and a physical activation consisting in a mechanical exfoliation of the leached layers formed by the (sub-)products on the particle surface. This coupled process involves complex elementary steps, both in solution (dynamic equilibrium between the primary ligands and the molecular adducts containing CO2, which interact specifically with the matrix elements and impurities of these phases) and on the reactive surfaces (size reduction, amorphization, surface complexation). Their optimization thus requires dedicated thermo-kinetic approaches associated with athorough physico-chemical analyses in order to propose a generic answer. The proposal also aims to move the process to higher TRLs by studying its scale-up, and by proposing a technico-economic and life cycle analysis integrating not only the energy aspect, but also the regeneration of the additives and their reinjection into the concrete production line and the recovery of the various metals.