Mechanosorption of carbon dioxide by Ca- and Mg-containing silicates and alumosilicates: Kinetic regularities and correlations with the dissolution of CO2 in silicate melts

The kinetics of the deep mechanosorption of carbon dioxide by natural and synthetic silicates and aluminosilicates (labradorite (CaAl 2 Si 2 O 8 ) 0.562 (NaAlSi 3 O 8 ) 0.438 , oligoclase (CaAl 2 Si 2 O 8 ) 0.148 (NaAlSi 3 O 8 ) 0.852 , diopside CaMgSi 2 O 6 , akermanite Ca 2 MgSi 2 O 7 , gehlenite Ca 2 Al 2 SiO 7 , and wollastonite CaSiO 3 in the course of mechanochemical activation in an AGO-2 centrifugal planetary mill at CO 2 pressure of 10 5 Pa is studied. Equations are proposed that make it possible to calculate coefficients of mechanosorption that characterize the ability of CO 2 molecules to penetrate into the disordered silicate matrix of minerals under intense mechanical actions with the formation of carbonate ions. Solubilities and diffusion coefficients of CO 2 at temperature of 1900 K and pressure of 1500 MPa in silicate melts, the compositions of which coincide with those of studied materials, are calculated using published data. Correlations are revealed between the degree of silicate carbonization upon mechanochemical activation in carbon dioxide and the solubility of carbon dioxide in silicate melts with analogous compositions, as well as between coefficients of mechanosorption and diffusion of CO 2 in melts.