Studies of the growth and dissolution kinetics of the CaCO3 polymorphs calcite and aragonite .2. The influence of divalent cation additives on the growth and dissolution rates

The influence of the divalent cations Fe2+, Cu2+, Zn2+, Mg2+, Sr2+, and Ba2+ on the growth and dissolution rates of calcite and aragonite has been studied. In most cases the results can be interpreted by a reversible adsorption of the impurity ions at kinks sites according to the Langmuir-Volmer model. Ions of the transition metals show a stronger inhibition than earth alkaline ions. Mg2+ and Fe2+ have no influence on growth and dissolution of aragonite. Further, Cu2+, and Zn2+ have a stronger effect on calcite, while Sr2+, and Ba2+ are more effective on aragonite. Results are used to show consequences for the polymorphic precipitation of CaCO3.