The influence of calcium nitrate on the process of carbon dioxide absorption in aqueous monoethanolamine (MEA) solution has been considered. The experimental data obtained under typical conditions used for the industrial precipitation of calcium carbonate has been used to determine the speciation in solution and the supersaturation profile in the bulk liquid by means of a specially developed algorithm as well as the kinetic regime of the absorption process in a pure aqueous solution and in the presence of calcium species at 30 degreesC using equilibrium and kinetic data from the literature. As expected, in pure MEA solution carbon dioxide reacts with MEA yielding ethanolammonium carbamate, whereas in the presence of calcium nitrate the process shifts towards CaCO30 ion pair formation, resulting in a continuous increase of the supersaturation generated during the "induction period" of calcium carbonate precipitation. The proposed reaction mechanism is supported also by the precipitate morphology determined by SEM analysis.