The mechanism of the mechanically assisted mineral carbonation of commercial olivine under flow of CO2/N2 mixture has been elucidated by ex situ powder X-ray diffraction and Fourier-transform infrared spectroscopy. The overall CO2 conversion depends to the rotation frequency of the mill’s engine, and reached 85% within 90 minutes of mechanical treatment, at a flow rate of 2.5 l min-1. By tuning the frequency rotation, the kinetics of CO2 conversion changed from a sigmoid behaviour into a more complex reaction pathway, involving subsequent steps. The structural analyses suggest the clinochlore, a Mg- and Fe- containing aluminosilicate gathered among the components of olivine, is formed and consumed in different stages, thus promoting the CO2 sequestration that eventually results into the formation of hydrated and anhydrous Mg-based carbonates.