Kinetic leaching studies using methanesulfonic acid (MSA) as an eco-friendly lixiviant for high nickel NCM black mass leaching

The rapid increase of electric vehicles and energy storage systems has driven the demand for lithium-ion batteries, resulting in an increase in spent battery generation. Valuable metals such as Li, Mn, Co, and Ni can be recovered from spent lithium-ion batteries through hydrometallurgy; however, conventional inorganic acid methods raise environmental concerns. This study investigated the use of methanesulfonic acid (MSA) as a greener lixiviant for leaching NCM black mass. Leaching tests were conducted with MSA and hydrogen peroxide (H₂O₂). The leaching results showed that increments in both MSA and H₂O₂ concentrations enhanced the metal leaching efficiency. The highest metal leaching efficiencies of 99.8 % (Li), 99.9 % (Mn), 95.42 % (Ni), and 96.82 % (Co) were observed at 1.0 M MSA and 1.5 M H₂O₂ at 80℃. Kinetic analysis using the shrinking core model identified diffusion through the product layer as the governing mechanism across all conditions. The reaction order exhibited stronger dependence on MSA than on H₂O₂. Apparent activation energies were ≈ 0 kJ/mol for Li and Mn, 24.96 kJ/mol for Co, and 31.36 kJ/mol for Ni, assigning Li and Mn to the mass transport-controlled mechanism and Co and Ni to the mixed controlled mechanism.