Validation of a Novel Anticlogging Microreactor by Using Continuous-Flow Synthesis of High-Purity Lithium Carbonate

Owing to small channel dimensions of microreactors, they are highly susceptible to clogging by solid particles generated within reaction systems, which severely restricts their applications on solid-forming reactions. To address this challenge, we developed a microstructured continuous stirred-tank reactor (micro-CSTR) that preserves the superior mixing characteristics while effectively fragmenting in situ generated particles under strong shear effects from rotational rotors. Initially, the mixing performance of micro-CSTR was experimentally investigated with the micromixing time as a key index. Under the conditions of a flow rate of 20 mL·min–1 and a rotational speed of 1500 rpm, the micromixing time is merely 0.3 ms. Next, the maximum solid content limit (12.5 wt %) for stable operation of the micro-CSTR was determined and was found to be significantly higher than the conventional microreactors (1–3 wt %). Moreover, CFD simulations were conducted to investigate the hydrodynamics and particle distribution inside the first mixing chamber of micro-CSTR, leading to deep mechanism understanding regarding the uniform suspension and discharge of solid particles with the liquid phase without channel blockage. With the excellent micromixing performance and strong anticlogging ability of micro-CSTR, lithium carbonate synthesis experiments were conducted, and the as-synthesized lithium carbonate particles exhibit not only a high purity (>99.5 wt %) and crystallinity but also a narrower particle size distribution and a smaller average particle size (8–13 μm) in comparison with those prepared via the batch reactor.