CO2 microbubbling system for lithium carbonate precipitation

Abstract

Lithium carbonate (Li2CO3) is becoming increasingly valuable with the growth of the lithium-ion battery industry. For effective Li2CO3 production, the efficient supply of the carbonate source to the solution is crucial. Conventionally, sodium carbonate has been used as the carbonate source; however, the importance of CO2 utilization has been recently recognized. Conventional CO2-based carbonate sourcing exhibits limited efficiency. In this study, we propose a CO2 microbubbling system based on a rotating nozzle for Li2CO3 precipitation. The CO2 micro-bubbling system demonstrated a 1.6 to 1.9 times greater precipitation reaction rate than that of the conventional CO2 bubbling system. This rate enhancement could be attributed to the increased gas-liquid contact surface and greater residence time due to the generation of CO2 microbubbles. Additionally, the Li2CO3 reaction terminated when the pH of the solution dropped below 9.4–9.7 approximately. The re-dissolution of precipitated Li2CO3 occurred below this pH range as bicarbonate ions became the dominant species over carbonate ions. This study successfully demonstrated that CO2 microbubbling technology could be an excellent alternative for carbonate sourcing systems in the Li2CO3 production industry.