Synergetic effect of secondary nucleation and growth on the lithium carbonate particle size in the gas–liquid reactive crystallization of LiCl–NH3·H2O

Tian, M., Guo, J., Wang, Z., Cao, J., & Gong, X. (2020). Synergetic effect of secondary nucleation and growth on the lithium carbonate particle size in the gas–liquid reactive crystallization of LiCl–NH3·H2O–CO2. Particuology, 51, 10-17. https://doi.org/10.1016/j.partic.2019.10.006

Synergetic effect of secondary nucleation and growth on the lithium carbonate particle size in the gas–liquid reactive crystallization of LiCl–NH₃·H₂O–CO₂

Menghua Tian^{a b}, Jianwei Guo ^{a b}, Zhi Wang ^{a b *}, Jianwei Cao ^a, Xuzhong Gong ^{a b}

a Key Laboratory of Green Process and Engineering, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
b School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China

10.1016/j.partic.2019.10.006

Volume 51, August 2020, Pages 10-17

Received 28 June 2019, Revised 26 September 2019, Accepted 12 October 2019, Available online 24 December 2019, Version of Record 11 April 2020.

E-mail: zwang@ipe.ac.cn

Highlights

• Weak alkaline nature of NH₃·H₂O yields unimodal Li₂CO₃ particle size distributions.

• Supersolubility and secondary nucleation rate decreased as temperature increased.

• The Li₂CO₃ mean particle size increased as a function of temperature.

• With improved supersaturation the Li₂CO₃ mean particle size decreased significantly.

• Supersaturation regulates PSDs by influencing secondary nucleation and growth rates.

Abstract

In this study, the gas‒liquid reactive crystallization of LiCl–NH₃·H₂O–CO₂ was adopted to produce Li₂CO₃. The weakly alkaline nature of NH₃·H₂O in the absence of any recarbonation process resulted in a unimodal and easily controllable particle size distribution (PSD) of the obtained Li₂CO₃. The reaction temperature significantly influenced both the Li₂CO₃ particle size and PSD. By increasing the temperature from 25 to 60 °C, the volume weighted mean particle size increased from 50.5 to 100.5 μm, respectively. The Li₂CO₃ secondary nucleation rate and growth rate were obtained by focused beam reflectance measurements and a laser particle size analyzer, respectively. The secondary nucleation rate of Li₂CO₃ reduced as a function of temperature, whereas the growth rate increased. In addition to improving the surface energy of the crystals to enhance the growth process, higher temperatures also reduced the supersolubility of Li₂CO₃, which also plays a role to decrease the secondary nucleation rate. At a constant temperature, supersaturation affects the Li₂CO₃ particle size through the synergistic effect of secondary nucleation and growth. Hence, with improved supersaturation, the mean particle size of Li₂CO₃ decreased. The results provide a meaningful way to evaluate the crystallization process and to regulate the particle size.

Graphical abstract

Keywords

Li₂CO₃; Gas–liquid reactive crystallization; Particle size distribution; Supersaturation; Secondary nucleation; Growth rate

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