The characterization of BM is critical for optimizing recycling processes that aim to recover valuable materials such as Ni, Mn, Co, Li, and graphite from NMC-based end-of-life LIBs. This study has thoroughly investigated the physicochemical properties of three BM samples obtained from NMC-based end-of-life LIBs to determine their implications for downstream pre-treatment and recycling processes. The findings demonstrate that the PSD of BM plays a crucial role, whereby sieving the BM into different size fractions helps in removing metallic impurities (Al and Cu) by concentrating them into the largest size fraction (+150 µm). Recovery of valuable metals and graphite can be enhanced by specifically subjecting the small-size fraction to the leaching process and the mid-size fraction to the flotation process, respectively. A method for measuring CLD of BM using the FBRM technique has also been developed to allow for real-time monitoring of particle size during the downstream pretreatment and recycling processes. The results showed that the application of square-weighting in the FBRM technique resulted in reliable measurements which were found to be closest to the results obtained from the laser diffraction technique.