Separation of Magnesium and Lithium from Brine with High Mg/Li Ratio Using A336P204

Abstract

In this study, the ionic liquid methyl trioctylammonium di-(2-ethylhexyl) phosphate (A336P204) was prepared to extract magnesium (Mg) from brine with a high Mg/lithium (Li) ratio. The effects of the extraction time, the pH of the initial aqueous phase, the volume fraction of ionic liquid in the organic phase, and the phase ratio on the extraction efficiencies of Mg²⁺ and Li⁺ were investigated. Under the optimal conditions, the single extraction efficiencies of Mg²⁺ and Li⁺ were 90.5% and 11.5%, respectively. The stripping efficiency of Mg²⁺ reached 93.3% using 1 mol/L HCl as a stripping agent with a volume ratio of the aqueous phase to the organic phase of 2. A336P204 has good cyclic stability, indicating its high potential for Mg²⁺ extraction from Mg²⁺-rich solutions.