Leaching Mechanisms of Industrial Powder

In view of a sustainable recycling process, the leaching mechanisms of nickel and rare-earth elements (REEs) contained within industrial samples of spent nickel metal hydride battery powders were investigated in HCl and H2SO4, under mild temperature (25-60 °C) and pH (3-5.5). First, an in-depth characterization of the heterogeneous battery powder was carried out utilizing techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microanalyzer wavelength-dispersive spectroscopy (EPMA-WDS) for quantitative analyses of individual particles, and inductively coupled plasma optical emission spectrometry (ICP-OES) for elemental analysis. The study confirmed the presence of critical metals and outlined the factors influencing their leaching behavior, providing insights into potential recycling applications. These results highlight the feasibility of using spent nickel metal hydride batteries as a resource for recovering valuable materials and emphasize the importance of developing effective processes for their recycling. Overall, the research contributes to the ongoing efforts to create a more sustainable approach to metal extraction and waste management in the field of electronic waste recycling.