Calcite dissolution kinetics in the system H 2OCO 2CaCO 3 with participation of foreign ions

Abstract

The effect of foreign ions on the dissolution kinetics of calcite was studied. Although foreign ions displace the calcite solution equilibria, by the effect of ion-strength, ion-pairing and the common-ion effect, the kinetics of the dissolution process are hardly changed. The first part of this paper treats these effects from the theoretical point of view. Experiments on the effects of foreign ions are in close agreement with theoretical predictions. Additional experiments with different limestones show that the effect of lithology on calcite dissolution kinetics is small, even for rather impure limestones. For the range of concentrations of foreign ions as found in most natural waters, the dissolution rates of calcite are similar to the dissolution rates found in the pure system H 2OCO 2CaCO 3 which were published earlier.