Metals Recovery from Spent Lithium-Ion Batteries: Synthesis and Physicochemical Properties of New Extractants for Solvent Extraction Processes

Abstract

Cobalt, nickel, lithium and manganese are strategic metals from many applications including alloys manufacturing, electrode materials for lithium-ion batteries (LIBs), etc. Their recovery from spent materials is a good opportunity from economical and geopolitical viewpoints. Indeed, these metals are expensive and recycling will reduce considerably their supply risks in the forthcoming years due to likely emergence of electric vehicles. Therefore, recovery of cobalt, nickel manganese and lithium from LiBs is strategic and development of efficient and economic processes is coming to the fore. Several research activities were carried out to recycle strategic metals from spent batteries by different methods such as pyrometallurgy, hydrometallurgy and biohydrometallurgy. Pyrometallurgical processes are however energy intensive and release gases like sulfur dioxide and carbon dioxide which are harmful to the environment. In recent past, metallurgical industry has been searching for hydrometallurgical processes due to some advantages such as possibility of treating low-grade resources, easier control of wastes and lower energy consumption. Hydrometallurgical processes are based on physical separation, leaching, purification, precipitation and in some cases electrowining. The demand for high purity metals and recent trends towards environmentally friendly technologies have focused more attention onto solvent extraction because this technology is mature and permits to achieve high extraction efficiency at low operating costs. Although extractant molecules are at the center of concern to achieve high efficiency and high selectivity of metal recovery in hydrometallurgical recycling processes, only few teams focus their research on the synthesis of new extractants. In this paper, extraction properties of new extracting agents for the recovery of cobalt, nickel, manganese and lithium will be presented after a brief overview of challenges and drawbacks in the development of lithium-ion batteries recycling processes. Extraction equilibria and relationships between their chemical structures and their extraction properties will be discussed. A flow sheet will be then deduced from experimental data provided in this paper to recover lithium, cobalt, nickel and manganese from spent cathodes contained in LiBs. A. Chagnes, B. Pospiech, "A brief review on hydrometallurgical technologies for recycling spent lithium-ion batteries”, Journal of Chemical Technology and Biotechnology 88, 1191-1199 (2013).A. Chagnes, J. Swiatowska (Ed), “Lithium Process Chemistry: Resources, Extractions, Batteries and Recycling”, http://dx.doi.org/10.1016/B978-0-12-801417-2.00005-0, ISBN 978-0-12-801417-2, Elsevier (2015).