Ion‐“distillation” for isolating lithium from lake brine

Abstract Lithium demands increase dramatically and make it highly attractive to develop advanced ion separation technology/material. However, high Mg 2+ /Li + ratio impedes the extraction due to the difficulties in separation of the two ions. Here, we propose an ion‐“distillation” technology based on electro‐membrane stacking for the extraction of Li + from lake brine (Mg 2+ /Li + ratio: 31.58). This technology employs commercially available monovalent ion‐selective membranes, and ions are driven by electric. Using the four‐stage ion‐“distillation” technology, selectivity values of 26,177 and 27,000 are achieved between Li + and Mg 2+ and between Cl − and SO 4 2− , respectively. The electro‐stripping mechanism when monovalent ion migrating across the membranes probably magnitude the Li + selectivity, which is higher than the other reported values in the literature for membrane processes, and the purity of the final LiCl product is greater than battery grade (99.95%). The proposed process can potentially be applied in efficient ion fractionation and special separations.