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

Dongxiang Zhang; Xianglei Zhang; Leilei Xing; Zirui Li

doi:10.3390/membranes11090697

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

Membranes (Basel). 2021 Sep 10;11(9):697. doi: 10.3390/membranes11090697.

Authors

Dongxiang Zhang^{1

2

3}, Xianglei Zhang¹, Leilei Xing^{2

3}, Zirui Li^{2

3}

Affiliations

¹ College of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou 325000, China.
² School of Mechanical Engineering, Hebei University of Technology, Tianjin 300401, China.
³ National Engineering Research Center for Technological Innovation Method and Tool, Tianjin 300401, China.

Abstract

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.

Keywords: ion concentration polarization; lithium extraction; membrane separation; nanofluidic.

Abstract

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