Systems and methods are provided for using a two-step process to capture CO2 from a process flue gas in an aqueous solution followed by conversion of the captured CO2 into metal carbonates for storage, transport, or other potential uses. In the first processing step, CO2 is removed from a process flue gas by contacting the process flue gas with an aqueous solution at a sufficiently high pH to enhance capture of the CO2 while reducing or minimizing other impacts on the vessel where capture is performed. The CO2-enriched aqueous solution is then passed into a second zone, such as a second vessel, for contact with a metal reagent, such as a metal oxide, metal sulfide, metal hydroxide, and/or metal silicate.