Coupled DEM-LBM simulation of saturated flow velocity characteristics in column leaching

Heap leaching is a process extensively used by the mining industry to recover valuable metals from low-grade ores. However, the flow of the solution in a heap leaching system is disordered, uncontrollable and difficult to predict. To investigate the velocity characteristics of saturated flows in column leaching under different conditions, a combined experimental and numerical approach was carried out in the current work. MRI (magnetic resonance imaging) technology was employed in the column leaching experiment and numerical simulations were performed by combining the discrete element method (DEM) with the lattice Boltzmann method (LBM) to predict the microscopic seepage velocity field in the leaching column. The fluid flow and solid particles were modelled by the LBM and DEM respectively, and the interfacial interaction between the fluid and the solids was resolved by the immersed boundary method (IMB). It was demonstrated that the maximum fluid velocity is positively correlated with irrigation rate and porosity. Moreover, the preferential flow mainly passes through the main seepage channel. Thus, the numerical model developed in the present work is a reliable prediction tool for understanding the regularities of mesoscopic seepage velocity distributions in column leaching processes.