CFD Modelling of the Spiral Concentrator at Moderate Feed Solids Content-Prediction of Particle Segregation

The current study aims to understand the particulate flow of the LD9 coal spiral concentrator using a multi-phase Computational Fluid Dynamics (CFD) model. The CFD model utilizes the Algebraic slip mixture model to simulate particulate flows. Initially, the volume of fluid (VOF) method and the Renormalization group k–ɛ turbulence model were adopted to track the water–air interface. The liquid depth and flow field predictions for varying flow rates were validated against the experimental literature data and found them in close agreement. Particulate flow simulations were then performed at low (0.3 and 3 wt%) and moderate (15 and 20 wt%) solids concentrations. Multiple particle-phase representing particles of poly sizes and multi-densities were simulated to study the particle segregation on the spiral trough surface. Predicted results showed close agreement with the experimental data. Further, this CFD model is used to study the change in pulp velocity, stream flow rates, and particle segregation at increasing solids concentration. For the same density particles, fines were mostly distributed in the middle and outer trough regions, whereas coarse particles were distributed in inner and central trough regions. Multi-phase flow predictions using the ASM model are promising to simulate particle dynamics at industrial feed solids concentration. The final implemented CFD model aids in designing the various spiral concentrators operating at moderate feed solids with different components.