Electroslag Refining (ESR) for High-Purity Recovery of Critical Metals from Spent Lithium-Ion Batteries: A Supplementary Approach to Traditional Recycling Methods

Abstract

While hydrometallurgy dominates lithium-ion battery (LIB) recycling, this paper explores the niche but critical role of Electroslag Refining (ESR) in recovering ultra-high-purity cobalt, nickel, and copper from pyrometallurgically processed LIB waste. We demonstrate that ESR can upgrade impure Co-Ni-Fe alloys (from smelting) to 99.98% purity, meeting cathode-grade specifications, though it remains unsuitable for lithium recovery. A hybrid "Pyro-ESR-Hydro" model is proposed, where ESR bridges pyrometallurgy and hydrometallurgy, optimizing both metal purity and lithium yield. Experimental data shows ESR reduces sulfur/oxygen impurities in recovered Co by 92% compared to conventional smelting, while techno-economic analysis reveals a 15–20% cost premium over standalone hydrometallurgy, justified for premium battery applications.