Effect of Metallic Ion on the Formation of Calcium Carbonate Fouling

Calcium carbonate (CaCO₃) is the most common fouling adhering on the surface of heat exchanger. But metallic ion in natural water could affect the crystalline type of calcium carbonate. In this study, the effect of sodium ion, magnesium ion and aluminum ion on crystalline type and morphology of CaCO₃ were reported. The experimental results indicate that the addition of sodium ion has no obvious role for changing the crystalline type of CaCO₃, only calcite was obtained and the lattice parameter of calcite has a little variation depending on the concentration of sodium ion. However, the addition of magnesium and aluminum ion prompts obviously the formation of aragonite. In order to clarify the mechanism about the effect of metallic ion on lattice stability of calcium carbonate, the energies and electronic structures for the calcite with sodium, magnesium or aluminum inclusion have been determined from first-principle calculations. The calculated results indicate magnesium and aluminum inclusion has more effects on the stability of calcite than that of sodium inclusion.