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The feasibility of using low-environmental-impact leaching media to recover valuable metals from lithium ion batteries (LIBs) has been evaluated. Several deep eutectic solvents (DES) were tested as leaching agents in the presence of different type of additives (i.e., H2O2). The optimization of Co recovery was carried out by investigating various operating conditions, such as reaction time, temperature, solid (black mass) to liquid (DES) ratio, additive type, and concentration. Leaching with final selected DES choline chloride (33%), lactic acid (53%), and citric acid (13%) at 55 °C achieved an extraction yield of more than 95% for the cobalt. The leaching mechanism likely begins with the dissolution of the active material in the black mass (BM) followed by chelation of Co(II) with the DES. The results obtained confirm that those leaching media are an eco-friendly alternative to the strong inorganic acids used nowadays. [ABSTRACT FROM AUTHOR]

The separation of graphite from cathode active materials containing Co, Ni, and Mn, and the metals Cu and Al by flotation was tested and evaluated with a black mass sample of crushed spent Li-ion batteries. The metals, Cu and Al, were mostly (>90%) concentrated by sieving into an oversize fraction (+0.25 mm). Graphite and the cathode active materials in the oversize fraction (+0.25 mm) were effectively separated from the metals, Cu and Al, by flotation. Pre-treatment by roasting at a temperature of 350–450 °C improved the flotation efficiency of graphite from the cathode active materials for the undersize fraction (−0.25 mm). [ABSTRACT FROM AUTHOR]