Nucleation and crystallization of CaCO3 in applied magnetic fields

Abstract

The formation of calcium carbonate is not only a common ionic reaction that takes place in natural processes, but also creates a problem known as scaling, which is present in our every day life and in various industrial processes and technologies. In spite of the simplicity of the reaction there is considerable variability in the properties of the solid product, such as: crystal form, particle size distribution, electro-kinetics potential, etc. The influence of the magnetic field on calcium carbonate precipitation has been known for a long time but despite a lot of effort, which has been made to explain this effect, researchers still disagree on the mechanism(s) responsible for it. The focus of our research work was to follow systematically the influence of the magnetic field on the crystal form of calcium carbonate precipitated from low concentration water solutions. By changing the strength of the field and the flow rate of the water through the system the calcite/aragonite/vaterite ratio varied. The crystal form and the particle-size distribution of the precipitated calcium carbonate were determined by using X-ray analyses and TEM. The theoretical part of the work was to study the mechanism of the influence of the magnetic field on the nucleation and further crystallization of calcium carbonate. Starting from ab initio calculations the fundamental physics knowledge was used to propose a mechanism for a better understanding of the phenomena.