Membrane crystallization for recovery of lithium carbonate crystals: Study on process parameters and salts effect for Li2CO3-NaCl-KCl-LiCl solutions

In this work, membrane crystallization (MCr) process was employed for recovery of lithium carbonate (Li2CO3) crystals from synthetic brine solutions. First, the effect of the main operating conditions in MCr, including feed temperature (40, 50, and 60 degrees C) and flowrate (0.81, 1, and 1.3 L/min) was investigated on the crystallization of Li2CO3 in a binary solution. Next, the effect of main inorganic salts in the brine solutions (i.e., NaCl, KCl, and LiCl) and the mixture of them on the MCr performance and crystallization of Li2CO3 were investigated. In-line microscope, light microscope, scanning electron microscope, and X-ray diffraction test were used to observe the crystallization and characterize the obtained crystals. The obtained results revealed that feed temperature is the main parameter to dominate the nucleation and crystal formation and growth. Thus, the higher the feed temperature, the faster the crystal formation and the larger the crystals. The average crystal size increased from 9.59 to 30.51 mu m, when the feed temperature increased from 40 to 60 degrees C, respectively. However, smaller crystals were observed with adding NaCl and KCl to the solution. Moreover, none of the operating parameters nor the salts additives did affect the crystals shape and the obtained Li2CO3 crystals possess needle-like shape.

Automated summary

In this study, membrane crystallization was used to recover lithium carbonate crystals from synthetic brine solutions. The effects of operating conditions and salt additives on crystallization were investigated. The results showed that feed temperature and the presence of NaCl and KCl had significant impacts on crystal size.