Improvement Study of Hydrometallurgical Treatment Process for Li-ion Batteries Waste

This study concerned the search for a method aimed at improving the safety of the treatment of Li-ion (Lib) battery waste. It consisted in the extraction of the electrolyte from used Libs by methanol before the hydrometallurgical treatment. As a result, the infrared extracts characterization, after concentration, revealed the presence of characteristic vibrations of organic functions or chemical bonds other than those of the methanol used, prompting the search for other constituents (P, F, Li) generally found in the electrolyte compositions of Lib. Furthermore, the pretreated cathodes are cut and subjected to selective leaching with 4N NaOH for 60 minutes according to a liquid/solid ratio L/S=10 L/Kg at ambient temperature. Alkaline leachates and black residues were quantified by X-ray fluorescence and results showed higher recovery rates for aluminum. It thus seemed that the pretreatment of the cathodic samples decreased the leaching rates. In addition, the pre-treatment of the samples has been shown to reduce the polluting nature of selective leaching, and the extraction of the electrolyte by methanol allowed the recovery of copper at the anode without any hydrometallurgical treatment.