Abstract: To systematically elucidate the differences in flow field characteristics and underlying mechanisms between two typical self-aerated flotation machines, namely the XJM-S and Wemco flotation machines, full-scale three-dimensional numerical simulations were conducted using computational fluid dynamics (CFD). Two flotation machines with identical tank volumes were selected as research objects. The Mixture multiphase flow model and the SST k-ω turbulence model were employed, while the multiple reference frame (MRF) method was adopted to simulate the rotating impeller region. A comprehensive comparative analysis was performed from multiple perspectives, including velocity distribution, pressure field, turbulence intensity, gas holdup distribution, and impeller shaft power consumption. The results demonstrate that significant differences exist in the flow organization mechanisms of the two flotation machines. The XJM-S flotation machine achieves efficient separation through a three-dimensional “W”-shaped circulation pattern, in which strong mineralization occurs in the lower part of the tank while a stable separation environment is established in the upper region, resulting in a well-ordered and hierarchical flotation process. In contrast, the Wemco flotation machine, characterized by a single large-scale circulation pattern and shallow tank configuration, effectively reduces energy consumption. This study reveals the intrinsic relationship between structural characteristics and flow field performance of the two flotation machines, providing theoretical guidance for flotation equipment selection and process optimization.