Abstract

This study explores the liberation of valuable metals from spent Lithium Ion Batteries (LIBs) following cryogenic grinding with varying grinding times, frequencies, and particle sizes. We characterize the physicochemical changes in lithium metal oxide particles focusing on the mineral phases, semi-quantification, and liberation of Co, Ni, and Mn. A total of 18 cathodic material samples underwent cryogenic grinding. Additionally, one sample was processed through conventional grinding for comparison. Grinding variables included frequencies of 10, 20, and 30 Hz, and durations of 3, 5, and 7 min. Subsequently, all tests were analyzed to determine their D80 value. The response surface methodology was used to ascertain the frequency and time variables with the greatest influence on D80 values. A predictive regression model was then applied to find the best D80 value. This statistical analysis was also used to choose the samples for X-ray Diffraction (XRD), Scanning Electronic Microscope − Energy Dispersive Spectroscopy (SEM-EDS), and Quantitative Evaluation of Minerals by Scanning Electron Microscopy (QEMSCAN) characterization. Characterization results revealed that LiCoO2 and Co3O4 particles have distinct spatial distributions compared to (Li0.65Ni0.05)(NiO2) and Li1.27Mn1.73O4 particles, which exhibited similar spatial distributions. LiCoO2 and Co3O4 particles achieved a high degree of liberation at 20 and 30 Hz frequencies and were liberated even at coarser particle size distributions of approximately < 450 μm when the frequency was equal to 10 Hz. In contrast, (Li0.65Ni0.05)(NiO2) and Li1.27Mn1.73O4 particles demonstrated a much lower degree of liberation tending to aggregate and be locked, but they were liberated at < 38 μm size distributions at all frequencies analyzed. Results show that cryogenic grinding is superior to the traditional grinding method. Furthermore, the specific results of the predictive regression model indicate the optimal D80 value of 55.82 μm can be achieved with a grinding frequency of 39 Hz and 7 min of constant grinding, enhancing the overall recovery efficiency for all target metals. © 2025 Elsevier Ltd