Carbon dioxide sequestration as mineral carbonates
The volume of carbon dioxide associated with the use of fossil fuels to generate electricity is enormous.Carbon dioxide is one of the major greenhouse gases whose concentration in the atmosphere has threatened the living environment of mankind.The advantages of a mineral CO_2 mitigation scheme are presented.Enormous deposits of ultramafic rock such as serpentine [Mg_3Si_2O_5(OH)_4] and olivine [(Mg, Fe)_2SiO_4] exist in nature, providing a large potential capacity of CO_2 sequestration.The resulting magnesite product is thermodynamically stable and environmentally benign, and the overall process is exothermic with the potential to be implemented with acceptable economics.In this study,the theory of mineral carbonation was discussed.An experimental bench scale unit was established and some experiments were made on different conditions of carbonation.X-ray diffraction analysis(XRD) identified magnesite as the primary reaction product, and under optimal conditions 58% stoichiometric conversion of the silicate to carbonate was achieved in 60 minutes.