Process intensification for the synthesis and purification of battery-grade Li2CO3 with microfluidics

Battery-grade lithium carbonate (Li ₂CO ₃ ) with a purity of higher than 99.5 wt% is of great importance as a high value-added lithium salt. However, influences of different reaction systems and process control on product purity remain unclear. Herein, a membrane dispersion microreactor was used to enhance the mass transfer of preparation and purification processes in homogeneous and heterogeneous system. Synthetic systems of Na ₂CO ₃–LiCl, NH ₄HCO ₃–LiCl, and NH ₃·H ₂O−CO ₂−LiCl, CO ₂ purification based on carbonation and decomposition were adopted. The Li ₂CO ₃ purity was increased by the improvement of mixing performance. The carbonation time was reduced by 62.5% and 58.3% for the NH ₃·H ₂O−CO ₂ and CO ₂ purification systems, respectively. In the two ammonia-based systems, Li ₂CO ₃ particles with a purity of 99.7–99.8 wt% were one-step prepared with a size of 3–5 μm, which also met the requirement of the battery-grade standard. The purity was further increased to 99.9 wt% by CO ₂ purification and LiHCO ₃ decomposition. The investigation could provide a feasible alternative for the controllable preparation of battery-grade Li ₂CO ₃ in one or multiple steps.