Effects of magnetic field on calcium carbonate precipitation: Ionic and particle mechanisms

There are two most widely reported mechanisms to study the effect of magnetic fields on calcium carbonate (CaCO₃) precipitate, namely ionic and particle mechanisms. The effects are most debatable because they are contrary to each other. This study explored the effects of both mechanisms in CaCO₃ deposit and total CaCO₃ precipitation using ionic and particle methods. The ionic method showed reductions in CaCO₃ deposit and total precipitation rate of CaCO₃, whereas the particle method showed the opposite results. The particle number decreased and the average particle diameter of CaCO₃ deposit increased in the ionic method. Meanwhile in the particle method, the particle number increased, average particle diameter decreased and particle aggregation of CaCO₃ was observed. XRD measurement on all deposits showed that the crystal deposit was mostly of calcite and the traces of vaterite. However, the amount of the crystal in the particle method was observed to be less than that in the ionic method, indicating that CaCO₃ deposit was more amorphous. Particle mechanism decreased the Ca²⁺ ion concentration in solution during magnetization, and ionic mechanism reduced scale (CaCO₃) formation after magnetization and separation processes. This method could be applied for decreasing water hardness and prevent the formation of scaling.