Mesoscopic flow simulation to understand the percolation through fine-ground electronic waste particle bed

Mechanical size reduction is a critical pretreatment for hydrometallurgical recovery of valuable metals in electronic waste. The particle size resulting from milling ranges from a few micrometers to a few millimeters, presenting challenges of achieving sufficient leaching percolation in portions occupied by fine particles. This work investigates the hydrodynamics of percolation through micrometer-sized fine particle beds by using many-body dissipative particle dynamics flow simulations. The results show that higher effective pore size resulting from high aspect-ratio particle packing contributes to higher permeability than spherical particle packing. Increasing surface wettability enhances maximum saturation rates but reduces permeability. Moreover, increasing tortuosity negatively impacts permeability and the degree of reduction in permeability caused by increased surface wettability decreases with increasing tortuosity. These findings imply possible complex relationships between tortuosity, pore size, and surface wettability that collectively impact percolation in loosely packed fine particle beds and can be used to guide improvement in pretreatment. • A mesoscopic multiphase flow model is calibrated for percolation simulation. • Loose packing of high aspect-ratio particles enhances permeability. • Increasing surface wettability enhances saturation rate but reduces permeability. • Increasing tortuosity negatively impacts permeability. • Complex relations between tortuosity, pore size, and wettability dictate percolation.