Progress in carbon dioxide sequestration via carbonation of aqueous saline wastes

In this article we report the progress made in CO2 sequestration research via formation of synthetic carbonates and explore the engineering aspects of the proposed methodology. The approach to synthesize carbonates involves the reaction of a flux of CO2 with Mg-chloride solution at room temperature. The kinetics of the carbonation reactions demonstrate that: a) in the experiments performed in solutions having both 7 and 16 g L-1 of Mg the rapid formation of nesquehonite occurred; b) in the experiments with 32 g L-1 of Mg an initial precipitation of chlorartinite was followed by the formation of nesquehonite and a minor amount of lansfordite. Carbonation via magnesium chloride aqueous solutions at standard conditions, here reported, represents a simple and permanent method of CO2 trapping in solid form. It could be applied at point-sources of CO2 emission and could involve rejected brines from desalination plants and other saline aqueous wastes. Other various aspects such as the influence of the salinity of the solution on the efficiency of carbonation and the kinetics of the reaction are also discussed.