Numerical Simulation of Continuous Extraction of Li⁺ from High Mg²⁺/Li⁺ Ratio Brines Based on Free Flow Ion Concentration Polarization Microfluidic System

• Main Authors: Dongxiang Zhang, Xianglei Zhang, Leilei Xing, Zirui Li
• Format: Article
• Language: English
• Published: MDPI AG 2021-09-01
• Series: Membranes
• Subjects: nanofluidic; lithium extraction; membrane separation; ion concentration polarization
• Online Access: https://www.mdpi.com/2077-0375/11/9/697

Ion concentration polarization (ICP) is a promising mechanism for concentrating and/or separating charged molecules. This work simulates the extraction of Li⁺ ions in a diluted high Mg²⁺/Li⁺ ratio salt lake brines based on free flow ICP focusing (FF-ICPF). The model solution of diluted brine continuously flows through the system with Li⁺ slightly concentrated and Mg²⁺ significantly removed by ICP driven by external pressure and perpendicular electric field. In a typical case, our results showed that this system could focus Li⁺ concentration by ~1.28 times while decreasing the Mg²⁺/Li⁺ ratio by about 85% (from 40 to 5.85). Although Li⁺ and Mg²⁺ ions are not separated as an end product, which is preferably required by the lithium industry, this method is capable of decreasing the Mg²⁺/Li⁺ ratio significantly and has great potential as a preprocessing technology for lithium extraction from salt lake brines.