Hydrometallurgical Process to Recover Cobalt from Spent Li-Ion Batteries

Abstract

The growth of the lithium-ion battery industry requires a secure supply of raw materials and appropriate end-of-life management of batteries. In almost five years, global cobalt consumption has increased by nearly 30%, driven mainly by rechargeable batteries. Consequently, several risks have been identified for cobalt, in particular the growing demand for electric vehicles, which could exceed current production. Therefore, research into the recovery of this critical metal, from industrial or urban waste, is particularly important in the years to come. In this study, cobalt is recovered from a lithium-ion battery leachate in hydroxide form. The thermodynamic simulations performed with Visual Minteq showed that it was possible to recover 99.8% of cobalt (II) hydroxide at 25 °C. Based on these results, experiments were conducted to validate the hypotheses put forward and to compare the results obtained with the simulations performed. Experimentally, several operating parameters were studied to determine the optimal conditions for cobalt recovery, in terms of yield, filterability, and selectivity. Results obtained in a batch reactor allowed the determination of the temperature conditions to be applied in continuous reactor. The cobalt (II) hydroxide precipitation in continuous reactor was carried out under different pH conditions. It was then possible to determine the optimal conditions for cobalt recovery in terms of yield and filterability. Results showed that working at pH 9 would effectively meet the desired criteria. Indeed, cobalt recovery is close to 100% and filtration flow rate is three times higher. Results obtained allow a better understanding of cobalt (II) hydroxide precipitation.

Literature Review, Recycling of Lithium-Ion Batteries from Electric Vehicles, Part I: Recycling Technology

“…Various hydrometallurgy techniques were developed in recent times for recycling cathode active materials of different chemistries LIBs including Lithium Cobalt Dioxide (LCO), Lithium Manganese Dioxide (LMO), Lithium Nickel Manganese Cobalt Oxide, (NMC), Lithium Nickel Cobalt Aluminum Oxide (NCA), and Lithium Iron Phosphate (LFP) [52], to recover valuable metals such as Co, Ni, Mn, and Li [53,54]. The whole hydrometallurgical process is created by physical and chemical methods proceeding in liquid media, which allow the high recovery of these metals [26,55,56].…”

“…[11]. The LIBs are discharged and separately treated to improve the safety and recovery rate of the whole process [55,57]. This operation allows the conservation of the minerals and efficiently separates the individual metals [55].…”

“…The first stage, "Leaching", contains dissolving or leaching of the valuable metals by acid or basic agent in an oxidizing or reducing medium in leaching tanks [55,57].…”

“…The second stage "Impurity removal" is created by solid-liquid separation, which clarifies the leach solution by filtration or centrifugation [55,62].…”

“…The last stage "Ni, Co, Mn, and Li recovery" is devoted to the final recovery of valuable metals in hydroxide or metal salts [55]. This process includes, for example, solvent extraction [63], electrochemical techniques [64], selective precipitation [65], and separation by ion exchange resins [55].…”