CO2 mineralization with natural phases is considered one of the most important methods for permanently sequestering carbon dioxide due to the abundance of suitable mineral resources. Among them, Olivine, a nesosilicate of magnesium and iron, has attracted attention due to its reactivity and high availability in nature. Ex-situ mineralization processes consist in reacting a slurry of the finely ground Olivine-containing rock in an aqueous NaHCO3 solution under high CO2 pressure at moderate temperatures producing a mixture of magnesium-iron carbonate and amorphous silica, with a nominal uptake of 0.63 tCO2/tOlivine, the highest among the common mineral phases. This reaction has been the subject of detailed studies since the early 2000s which have led to a profound knowledge of the reaction mechanism and kinetics. On the contrary, the possible uses of the mineralized phase have been little investigated, limited almost exclusively to its disposal, e.g., for the reclaiming of abandoned mining sites, to its use as an inert component in building materials or as filler of polymeric materials.
Realizing that the valorisation of the product is essential for the economic sustainability of the entire process, we have undertaken an activity aimed at identifying the possible uses of the mineralized phase. In particular, attention was focused on the cement industry, a sector defined as "hard-to-abate" which could benefit from the use of the product in the pathway of reducing its carbon footprint.
