Molecular Dynamic Regulation of Na and Mg Ions on Lithium Carbonate Crystallisation in Salt Lakes

Lithium carbonate (Li2CO3) was synthesised by adding sodium (Na) and magnesium (Mg) ions into a lithium chloride solution at different concentrations, followed by the addition of an appropriate sodium carbonate solution. Then, the morphology, purity and particle size of Li2CO3 crystals were investigated. The Na and Mg ions had negligible and remarkable effects, respectively, on the product purity; however they both greatly influenced its morphology. Their effects on the nucleation and growth rates, the radial distribution function and the diffusion behaviour of the synthesised Li2CO3 were investigated via molecular dynamics methods; the Na ions slowed down the crystal nucleation and growth rates, while the Mg ions accelerated them. Moreover, the Mg ions rendered the system short-range ordered and long-range disordered and also increased the diffusion coefficient. The results of this study showed that Mg ions are one of the most important factors influencing the purity and yield of Li2CO3.