In this study, the application of Z-shape pneumatic separator for separating metal and nonmetal particles in pyrolysis residue of waste printed circuit boards was investigated, and the flow field characteristics and particle motion behavior in the separator were revealed through flow field simulation. The pneumatic separation results indicated that pre-screening significantly enhanced the separation efficiency of metals and nonmetals in pyrolysis residue. The simulation results showed that the large gradient of airflow velocity distribution and the turbulent flow field within the Z-shape separation cavity are beneficial for dispersing particles and reducing the influence between particles of different properties, thus enhancing separation efficiency. Using Rocky DEM for modeling of different shapes and properties of particles, and then combined with ANSYS Fluent can better simulate the particle separation behavior in the pneumatic separator.