Facile synthesis of pure vaterite using steamed ammonia liquid waste and ammonium carbonate without additives via simple mechanical mixing

Abstract This paper describes a simple, low-cost, and fast method for synthesizing high-purity porous vaterite calcium carbonate (CaCO3) without any additives using steamed ammonia liquid waste and (NH4)2CO3. The obtained vaterite samples were characterized using various techniques such as powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and laser particle size analysis (LPSA). The XRD and FTIR analyses indicate that the prepared product is high-purity vaterite CaCO3. The SEM analysis shows obtained micro/nanosized spherical and porous vaterites. The effects of stirring mode and stirring speed on the morphology, particle size, and stability of vaterite were studied systematically. The stirring speed and stirring mode were found to play an important role in the crystallization of vaterite CaCO3 with different purities, morphologies, particle sizes, and particle size distributions. Based on the analysis of vaterite CaCO3 particles obtained under different stirring modes and stirring speeds, a possible mechanism for obtaining smaller vaterite CaCO3 particles at high stirring speed is proposed. The possible mechanism underlying the properties of ammonia-distilled waste liquid during vaterite formation is also discussed.