Selective Lithium Recovery from Spent Lithium Manganate Batteries Using Oxidative Stabilization Technique.

Abstract

Using oxidizing compounds to handle the recycling of discarded lithium batteries has advanced significantly in recent years. One of the most prominent methods is the sintered electrode powder treatment using pre-used additives, with an aqueous solution of the oxidizing agent fueling highly selective lithium extraction and transition metals retention in the refractory material. Herein, phosphoric acid (H₃PO₄) was used as the exchanger and hydrogen ions provider, the oxidant (K₂S₂O₈) activity was driven by heating, the raw material structure was deformed and adjusted by the oxidizing drive, and lithium was exhausted, while manganese was converted into manganese(III) phosphate hydrate and manganese dioxide insoluble material. The optimized conditions resulted in a lithium leaching rate of 94.16 % and a separation factor of 95.74 %, while the corresponding manganese leaching rate was limited to less than 5 %. The X-ray diffraction, X-ray spectroscopy, scanning electron microscopy, and inductively coupled plasma mass spectrometry measurements were used to investigate the influence of oxidation driving force and lithium leaching. Finally, the lithium leach solution was continuously stirred with sodium carbonate in boiling water to obtain the precipitate, which was separated and washed several times to obtain high-purity lithium carbonate.