The mechanosorption of carbon dioxide by magnesium, calcium, and strontium metasilicates

摘要

Processes that occurred in the mechanical activation of MSiO_3 silicates (M = Mg, Ca, Sr) in a centrifugal planetary mill in the atmosphere of carbon dioxide (p(CO_2) = 10~5 Pa) were comparatively studied. The interaction of carbon dioxide with silicates had the character of deep mechanosorption with massed penetration of gas molecules into the volume of particles and their "solution" in structurally disordered silicate matrices in the form of distorted CO _3~(2-) ions. No individual carbonate phases were formed. The absorbing ability of silicates with respect to carbon dioxide decreased in the series SrSiO_3 > CaSiO_3 > MgSiO_3. The carbon dioxide mechanosorption coefficients K _(MS) were calculated for Mg, Ca, and Sr silicates according to the earlier suggested kinetic model. A linear dependence of logK _(MS) on Δ_r G _(298)~o for the transformation of silicates into the corresponding carbonates was observed.