Continuous-flow synthesis of lithium carbonate in a microreactor system based on spent LIBs recycling process

With the continuous expansion of the lithium-ion battery market, the collection and recycling of spent lithium-ion batteries have gradually become a concern for researchers. In this research, based on the hydrometallurgical recovery process of spent lithium-ion batteries, an efficient and continuous synthesis process of industrial lithium carbonate was developed in a microreactor system. The effects of initial concentration of lithium solution, temperature and washing conditions on recovery rate of Li and product purity were investigated, and the optimal conditions of synthesis were obtained. Compared with the semi-batch method, the microreactor system had excellent mass and heat transfer characteristics. The product had good microscopic properties, uniform particle size distribution, and the recovery rate of Li reached 94.8 % with the purity of Li2CO3 reached 99.4 %, meeting the national standard of China for industrial grade lithium carbonate. The particle size distribution of the synthesized lithium carbonate was 6.2<D-50 < 7.1 mu m. Finally, the hydrometallurgical recycling process of spent cathode materials was well constructed in combination with leaching, co-extraction and separation steps of metal ions.