Deterministic lateral displacement method for the separation of fine and ultrafine rigid particles

Utilization of ultrafine particles becomes a major concern in the mineral processing industry with the advance in comminution and liberation techniques. The efficiency of ultra-fine particle treatment needs to be improved and microfluidic devices are selected as the potential alternative method. In this thesis, particle separation process in the microfluidic separation device named Deterministic Lateral Displacement (DLD) is studied. Single phase numerical simulation is performed to predict change of separation critical diameter when changing DLD pillar array design parameters. Then the CFD-DEM coupling simulation is performed to predict particle movement trajectory in the pillar array. Particle migration angle and residence time under different flow modes are achieved. Then a macroscale DLD separation device is built to verify simulation results. Inertial effect is found during experiment, which is eliminated by utilizing high viscosity liquid. Finally, the microscale DLD separation device is fabricated through microfabrication process. Different migration trajectories are found for small and large particles.