Polymorphic composition and morphology of calcium carbonate as a function of ultrasonic irradiation

Abstract

This paper reports on the precipitation of CaCO 3 polymorphs, having various crystal morphologies under different conditions. In particular, systems that were subject to ultrasonic irradiation were compared to the corresponding reference systems in the absence of such a treatment. The application of ultrasonic irradiation predominantly resulted in a change of particle size distribution and polymorphic composition of the precipitate, in comparison to the reference systems. Thus, it was found that the supersaturation and temperature influenced the size distribution, in both the reference and sonicated systems. A mixture of calcite, vaterite and aragonite was obtained in all reference systems, at 25°C. At this temperature, the sonication caused the vaterite content to increase, while aragonite was not detected. In reference and sonicated systems at 80°C, only aragonite precipitated. The results also indicate that the principle parameter responsible for the morphology of vaterite was the initial supersaturation: at higher supersaturation spherical vaterite particles precipitated, while at lower supersaturation hexagonal platelets were obtained. The morphological investigations also indicated different mechanisms of vaterite formation in the systems in which precipitation was initiated at higher supersaturation: spherulitic growth of vaterite was observed in sonicated systems, while the aggregation of primary particles was predominant in the reference systems. At lower supersaturation, the effect of c(Ca 2+ )/c(CO 3 2− ) on the morphology of hexagonal platelets of vaterite was observed as well. By varying the c(Ca 2+ )/c(CO 3 2− ), significant changes of the polymorphic composition were observed only in the sonicated systems, at 25°C.

Ultrasonic-assisted production of precipitated calcium carbonate particles from desulfurization gypsum

“…code: NH-V-UN and NH-V-UA). However, these findings do not agree with those from the previous study, in which ultrasonic treatment promotes an increase in the proportion of vaterite crystals [25] , [36] .…”

Synthesis and Adsorbing Properties of Tabular {001} Calcite Crystals

“…Thus, it can be concluded that, besides the adsorption, the calcite incorporates the Li + in the crystal structure, while vaterite particles can additionally entrap the Li-containing solution into the pores. Indeed, at the applied supersaturation level, vaterite spherulites are most probably formed by fast spherulitic growth, which is characterized exactly by the increased trapping of dissolved impurities, like Li + in this particular case [45,49,50].…”

“…However, a shortening of the induction time for vaterite formation, caused by applying more intensive agitation and seen as a pH drop, can be observed (ultrasonic < magnetic < mechanical). At that, the most likely mechanism of the promotion of nucleation in the case of sonication is a collapse of cavitation bubbles, which caused localized high pressure and temperature spots, while the literature data indicated that the energetic collisions among particles may enhance the transition of metastable vaterite to calcite as well [42][43][44][45]. In addition, the SEMs of the respective samples isolated after 5 days of aging ( Figure SI8) showed significantly different morphologies of calcite crystals.…”

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

“…An ultrasound irradiation technique has been applied to the formation of CaCO3 polymorphs (Price et al, 2011;Stoica-Guzun et al, 2012;Wagterveld et al, 2012;Njegić Džakula et al, 2014). The use of ultrasound can help control the crystallization process, and this is referred to as sonocrystallization (de Castro and PriegoCapote, 2007).…”