An environmentally friendly method for recovery of lithium and cobalt from spent lithium-ion batteries using gluconic and lactic acids

Abstract

The waste of lithium ion batteries (LIBs) is the major secondary source of valuable elements such as lithium and cobalt. Accumulation of spent LIBs can lead to environmental pollution and also the loss of valuable metals. In this study, recovery of lithium and cobalt form LIBs was investigated using a hydrometallurgy process. To optimize the leaching parameters (type of organic acids, acid concentration, solid to liquid ratio (S/L), temperature, and hydrogen peroxide concentration), response surface methodology (RSM) was applied. Gluconic and lactic acids were used for the leaching experiments and results showed that in both the cases of lithium and cobalt, lactic acid is more efficient than gluconic acid. While the leaching parameters were set at the temperature of 79 °C, lactic acid concentration of 1.52 M, S/L ratio of 16.3 g.L−1, and hydrogen peroxide concentration of 4.84 Vol.%, 100% of lithium and 97.36% of cobalt were recovered. The head sample and the leaching residues were analyzed by inductivity coupled plasma optimal emission of spectrometry, X-ray diffraction, and high resolution scanning electron microscopy.