Enhancing the efficiency of metals extraction from waste lithium-ion batteries through glycine leaching using response surface methodology for economic feasibility

Recycling of lithium-ion batteries (LiBs) has captured remarkable interest due to its potential to mitigate pollution and conserve natural resources and energy. This study is establishing an environment friendly method for metals leaching from LiBs utilizing glycine (NH2CH2COOH) as a leaching agent. Li dissolution is being investigated as a function of time, pulp density, glycine concentration, and temperature. The results are evincing the leaching of Li (around 94%) using 2 M glycine at 75 °C temperature, 50 g/L pulp density and 120 min mixing time. Response surface methodology (RSM) techniques are being employed to enhance the standard hydrometallurgical process. The kinetics of Li leaching are well fitted with the “chemical reaction-controlled process” equation of the shrinking core model (1 - (1 - x) 1/3 = kt) and the energy of activation is found to be 23.69 kJ/mol. Moreover, the economic evaluation of the leaching process reveals that at optimum conditions, the average profit response for treated metals is 2394.56 USD per tonne of black powder. Therefore, the use of glycine as a green extractant not only augmenting the leaching efficiency but also minimizing the usage of inorganic acids, proffering a better alternative for green recovery of waste LiBs in future.