Extraction of Ti(IV) Ions from Chloride Solutions with the Aliquat 336–Menthol Hydrophobic Deep Eutectic Solvent

Abstract Hydrometallurgical methods remain among the most promising for lithium-ion battery recycling, and liquid–liquid extraction is the key step in separating the complex mixture of elements that make up the anode and cathode. The development and complication of the composition of batteries, in particular, the active production of lithium titanate anodes, requires additional research on extraction. The work studied in detail the extraction of Ti(IV) ions with the Aliquat 336–menthol hydrophobic deep eutectic solvent, which was previously successfully used to separate elements from leaching solutions of NMC-type cathodes (LiNiMnCoO2). Data were obtained on the extraction of titanium(IV) ions with varying acidity of the medium, concentration of chloride ions, and concentration of the extractant in the deep eutectic solvent. Based on these data, a mechanism for the extraction of titanium(IV) ions was proposed. Finally, a system for efficient extractant regeneration was proposed. The result of this work can be used to create an extraction scheme for separating leaching solutions of lithium-ion batteries with a lithium titanate anode.