Efficient separation mechanism of multi‐metal ions under micro‐interface and fluid coupled mass transfer enhancement

Abstract Hydrometallurgy was the dominant process for recycling spent lithium‐ion batteries (LIBs). However, problems such as emulsification and attenuation of mass transfer efficiency in traditional solvent extraction have severely restricted its industrial application. Current studies prioritized extractant design over mass transfer enhancement, and unclear mechanisms of micro‐interfacial–hydrodynamic coupling hindered process optimization. To address these challenges, a reciprocating squeezing microchannel extraction system was constructed, establishing a quantitative structure–performance framework that systematically correlated flow field architectures with interfacial mass transfer dynamics and critical microextraction parameters, ultimately achieving synergistic optimization for sustainable recovery of strategic metals (Ni(II), Co(II), Mn(II)). Experimental validation demonstrated that microfluidic field intensification enabled continuous high‐efficiency separation of metal ions, with multidimensional characterization techniques (FTIR, UV–Vis, XPS, SEM‐EDS) fully proving the causal relationship between different influencing factors through both qualitative identification and quantitative analysis. The established micro‐interfacial–hydrodynamic coupling can effectively improve the defects in traditional processes.