Influence of stirring speed on the crystallization of calcium carbonate

Abstract

Control over crystal morphology of calcium carbonate (CaCO 3 ) was investigated by simply changing the stirring speeds in the process of CaCO 3 formation. Scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) measurements explore the morphology evolution of CaCO 3 at varying stirring speeds. As the stirring speeds increase, rhombohedral calcite, spherical vaterite, and monoclinic crystal with coexistence of calcite phase and vaterite phase were formed, suggesting a facile control over calcium carbonate crystallization in constructing crystals with desired morphology. Moreover, almost pure vaterite spherical particles of narrow particle size distribution were formed at optimum stirring speed. Finally, also elucidated in this work is the mechanism investigation into the construction of various crystal forms via this simple route.

Calcium Carbonate Precipitation for CO2 Storage and Utilization: A Review of the Carbonate Crystallization and Polymorphism

“…Yan et al (2009) examined the effect of the stirring rate on the precipitation of the CaCl2 and Na2CO3 solution with varying stirring rate (50-1,000 rpm). At a lower stirring speed (100 rpm), calcite phase was dominantly observed, and a further increase of stirring speed led to the formation of vaterite.…”

Kinetic control of particle-mediated calcium carbonate crystallization

“…29 Yan et al showed the importance of stirring rate for controlling CaCO 3 polymorphism also without additives. 30 A classical view of ionic growth of CaCO 3 crystals 31 cannot explain the observed behavior, as convection is a macroscopic phenomenon. In addition, the traditional view of nucleation and growth of calcium carbonates was recently challenged by Gebauer et al…”

Sub‐Micrometer Vaterite Containers: Synthesis, Substance Loading, and Release

“…[12] A particle size reduction beyond these values has so far not been achieved, since vaterite was found to become unstable in water below this critical size, leading to a rapid recrystallization to the calcite phase. [13] This recrystallization is due to the growing surface-to-volume ratio and enhanced solubility with decreasing particle size.…”