In this study, the precipitation of Li2CO3 was systematically studied in chloride and sulfate environments (Cenv and Senv) to assess its impact on parameters including pH, initial lithium concentration, temperature, and presence of co-ions, influencing the recovery efficiency and product purity as well as its morphology. Increasing the pH enhances the Li2CO3 recovery efficiency from 63.4% to 79.6% in Cenv and from 48.0 to 69.4% in Senv. The x-ray diffraction (XRD) analysis confirmed the crystalline structure of Li2CO3 produced in both environments. However, the scanning electron microscopy (SEM) images and particle size distribution analyses highlighted the strong influence of precipitation environment on the crystal morphology and the particle size distribution. Increasing the initial lithium concentration of the precipitation solution results in increased recovery efficiency in Cenv rather than that in Senv. The difference is attributed to the strong association of Li+ with the sulfate ion that restricts the availability of free lithium due to the enhanced electrostatic shielding effect, while such an ion pairing effect is weaker in the Cenv. Moreover, an increase in the initial lithium concentration causes a sharp reduction in the product purity and growing of the particle size in Cenv while a reduction of the particle size is observed in Senv. In Senv, the Fourier-transform infrared (FTIR) spectra indicate the incorporation of sulfate in the Li2CO3 lattice at higher temperatures. Conversely, increasing temperature results in smaller particles in Cenv whereas the SEM–EDS analyses revealed that Na2CO3 as the main impurity is reduced owing to lower lattice entrapment. Increasing the carbonate-to-lithium molar ratio from 1 to 2 improves the recovery efficiencies in both environments due to supersaturation of carbonate ions that enhances the nucleation and crystallization of Li2CO3. However, it promotes the precipitation of sodium-based impurities and significantly reduces the purity in Cenv (from 97.6 to 84.4%) while a consistently high purity (about 98%) is retained in Senv due to low interference of sulfate ions with Li2CO3 precipitation. The findings of this study underscore the role of ionic compositions in the control of precipitation performance. Graphical Abstract

A Comparative Study of Lithium Carbonate Precipitation in Chloride and Sulfate Environments

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发表日期：

2026年4月10日

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Anahita Kazemi Kia,
Mahyar Moemeni,
Ali Asghar Nozaeim,
Hamid Reza Mortaheb,
Mahsa Baghban Salehi

摘要

In this study, the precipitation of Li₂CO₃ was systematically studied in chloride and sulfate environments (C_env and S_env) to assess its impact on parameters including pH, initial lithium concentration, temperature, and presence of co-ions, influencing the recovery efficiency and product purity as well as its morphology. Increasing the pH enhances the Li₂CO₃ recovery efficiency from 63.4% to 79.6% in C_env and from 48.0 to 69.4% in S_env. The x-ray diffraction (XRD) analysis confirmed the crystalline structure of Li₂CO₃ produced in both environments. However, the scanning electron microscopy (SEM) images and particle size distribution analyses highlighted the strong influence of precipitation environment on the crystal morphology and the particle size distribution. Increasing the initial lithium concentration of the precipitation solution results in increased recovery efficiency in C_env rather than that in S_env. The difference is attributed to the strong association of Li⁺ with the sulfate ion that restricts the availability of free lithium due to the enhanced electrostatic shielding effect, while such an ion pairing effect is weaker in the C_env. Moreover, an increase in the initial lithium concentration causes a sharp reduction in the product purity and growing of the particle size in C_env while a reduction of the particle size is observed in S_env. In S_env, the Fourier-transform infrared (FTIR) spectra indicate the incorporation of sulfate in the Li₂CO₃ lattice at higher temperatures. Conversely, increasing temperature results in smaller particles in C_env whereas the SEM–EDS analyses revealed that Na₂CO₃ as the main impurity is reduced owing to lower lattice entrapment. Increasing the carbonate-to-lithium molar ratio from 1 to 2 improves the recovery efficiencies in both environments due to supersaturation of carbonate ions that enhances the nucleation and crystallization of Li₂CO₃. However, it promotes the precipitation of sodium-based impurities and significantly reduces the purity in C_env (from 97.6 to 84.4%) while a consistently high purity (about 98%) is retained in S_env due to low interference of sulfate ions with Li₂CO₃ precipitation. The findings of this study underscore the role of ionic compositions in the control of precipitation performance.

Graphical Abstract