Liquid-assisted irregular coarse particle fluidization in a tapered fluidized bed separator

• Low-grade coarse chalcopyrite particles fluidization using 3D-CFD modelling. • Fluidization behaviors between conventional and tapered HydroFloat separators. • Tapered HydroFloat separator offers low bed expansion at same initial bed height. • Higher apparent viscosity near dewatering zone in tapered HydroFloat separator. Tapered fluidized bed flotation can assist in enhancing the throughput and coarse particle separation. Here, a three-dimensional computational fluid dynamics (CFD) model is developed by utilizing the two-phase Eulerian-Eulerian multiphase approach, combining the RNG k-ε turbulence model for the liquid phase and the kinetic theory of granular flow for the particle phase. A modified drag model is developed to describe the interaction between the liquid and the irregular coarse particles. The predicted bed expansion using CFD shows an excellent agreement with available experimental and simulation data of the conventional HydroFloat separator (CHF), known as a fluidized bed flotation separator; the maximum relative error was 5.2 %. Thereafter, CHF geometry is modified to create a 2° and 4° tapered HydroFloat (THF) separator to study the complex characteristics of the irregular low-grade coarse chalcopyrite particles in liquid-assisted fluidization for two different fluidization velocities, 0.0085 ms −1 and 0.0145 ms −1 . Compared to CHF, the 4° tapered HydroFloat separator showed around 20 % and 35 % lower bed expansion for the mentioned velocities, respectively. The findings suggest that the tapered HydroFloat separator has great potential in terms of lower bed expansion with enhanced turbulence kinetic energy and dissipation rate.