Recycling of EV Li-ion batteries to reclaim valuable metals/ materials

Abstract

Due to the large dependency of Li-ion batteries for various applications such as electric vehicles, consumer electronics and energy storage, the huge amount of waste batteries are generated after the end use. Illegal recycling and disposal to environment are creating hazard to the environment as well as loss of valuables, particularly in developing countries, where environmental regulations are not yet implemented properly. On the other hand, several applications of cobalt and lithium, lack of natural resources, increasing demand and less availability compelled to find alternative resources for its extraction. The present paper is focused on the review as well as process developed by CSIR-NML to recover Co, Li, Mn, Cu, Ni, Fe, plastic, mix metals and graphite from waste Li-ion batteries using various techniques consists of pre-treatment followed by hydrometallurgical processes. First of all, waste Li-ion batteries are crushed and beneficiated to obtain plastics, mix metals and black cathodic materials. Generally it contained in wt. % 5-25 Co, 2-5 Li, 1-3 Ni, 7-10 Al, 6-10 Cu, 5-15 Fe, 5-25 Mn, 10-25 Graphite, 7-10 plastics etc. The contents in the batteries are very heterogeneous in nature depending on variety, quality and uses. Further black material containing Co, Li, Cu, Ni, Mn, Al was processed for metal leaching in suitable lixiviant i.e. 2M sulphuric acid, 10% H2O2 at elevated temperature and mixing time 1 hour. The leach liquor obtained was purified using advance separation techniques (SX/IX/precipitation) to get pure solution of individual metals. After filtration the obtained leach-liquor was processed for recovering MnO2 at optimised pH with the addition of precipitant. Leached residue containing graphite/carbon is saleable product. Further, Mn depleted solution was processed to recover Cu and Ni using cationic extractant LIX-84IC at eq. pH 2.5 and 4, respectively. Now, the solution was processed to get Co selectively by using Cyanex 272 at eq. pH 5.5. The Li from the raffinate was obtained as lithium sulfate by the evaporation process. Further, using crystallization/ electro-winning techniques value added products (salts/ metals) could be produced. The developed processes are eco-friendly, energy-saving and comply with stringent environmental regulations.