Batch Flotation of Lithium-Bearing Slag—A Special Focus on the Phase Properties of Engineered Artificial Minerals for Enhancing the Recycling of End-of-Life Lithium-Ion Batteries

The increasing demand for lithium-ion batteries (LIBs) and the critical need for lithium make the efficient recycling of secondary resources essential. Synthetic Li-bearing phases, some with lithium contents greater than natural sources (e.g., spodumene), can occur in slags produced by the pyrometallurgical recycling of end-of-life LIBs. This study investigates both the composition of synthetic model slags reproducing LIB recycling and the recovery potential of Li-bearing phases using SEM-based automated mineralogy and batch flotation tests, respectively. In particular, the efficacy of a novel zwitterionic collector, punicine, in contrast to the conventional collector, oleic acid, was evaluated with a focus on recovering Li-aluminate as a key engineered artificial mineral (EnAM). The flotation tests demonstrated that punicine provided a higher degree of selectivity for Li-aluminate over gehlenite, along with improved recovery of fine and well-liberated particles. The enhanced performance is attributed to punicine’s unique frothing properties and phase-specific interactions. Our findings highlight punicine’s significant potential as a collector for lithium-bearing EnAMs to advance lithium recovery from complex slag materials. The applied unique methodology supports the study of reagent regimes in relation to the flotation behavior of EnAM phases and the sustainable recycling of LIBs.