CO2 storage in solid form: a study of direct mineral carbonation

摘要: Direct mineral carbonation by an ex-situ process in aqueous system has been investigated over the past two years. The utilizes a slurry of water mixed with magnesium silicate mineral, such as olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. This is reacted sub- supercritical carbon dioxide (CO2) to produce magnesite (MgCO3). CO2 dissolved form carbonic acid (H2CO3), which dissociates H+ and HCO3-. ion hydrolyzes liberating Mg2+ cations react bicarbonate solid carbonate. Results baseline tests, conducted on ground products natural minerals, have demonstrated that kinetics reaction are slow at ambient temperature (22 C) subcritical pressures (below 73 atm). However, elevated pressure, coupled continuous stirring gas dispersion within column, significant conversion carbonate occurs. Extent roughly 90% 24 hours, 185 C partial pressure (PCO2) 115 atm. Heat pretreatment serpentine, salt additions solution, improve kinetics, resulting extent roughlymore » 80% 0.5 155 PCO2 Subsequent tests intended examine various options, solution characteristics, well other groups.« less