Extracting Li+ from high Na/Li solution and comparing the affinity of nonylphenol oxygen anion to Na+ and Li+

Abstract

Lithium extraction has become a hot topic because of global efforts to control carbon emissions. However, the efficient separation of Li/Na is a great challenge. In this study, the lithium carbonate precipitation mother liquor with Li⁺ content of 1.7910 g/L and Na⁺ content of 111.2438 g/L was used as the raw material solution. Due to its high Na/Li ratio, we found that the affinity of nonylphenol oxygen anion with Li⁺ is stronger than that with Na⁺ through quantum chemical analysis. And through the optimization of the effects of saponification degree, pH, temperature, and phase ratio, after twelve rounds of a five-stage countercurrent extraction, the E_Li (%) reached 99% and the maximum β_Li/Na reached 114799.73. After scrubbing with 0.5 mol/L HCl + 0.5 g/L LiCl solution and stripping with 2 mol/L HCl solution, Li⁺ and Na⁺ could be effectively separated. This study proved that nonylphenol oxygen anion had a significant effect on the extraction of Li⁺, and could effectively separate Li⁺ from Na⁺, which brings a new idea for the treatment of high Na/Li solution.