Continuous, dynamic and steady state simulation of the reflux classifier using a segregation-dispersion model

A 2D continuous segregation-dispersion model incorporating a laminar- shear separation mechanism has been developed to describe the Reflux Classifier (RC). The RC, which consists of a fluidization zone, and a system of closely-spaced inclined channels, is now widely used to achieve gravity separation of a broad range of commodities. The narrow inclined channels promote the laminar-shear mechanism, leading to the selective shear induced lift of low density particles, while allowing the fine and denser particles to deposit onto the inclined surfaces, and slide downwards. This mechanism allows a sharp density-based separation. The simulation results of this study have been validated using previously published experimental data. A total of 42 particle species were used in the simulations, corresponding to 6 different sizes and 7 different densities for each particle size, covering the particle size range of -2.0 + 0.125 mm. Simulation partition curves showed good agreement with the published experimental data, including the D-50 and E-p values over the particle size range -2.0 + 0.25 mm. The model has also been tested to investigate the effect of high solid throughputs on the separation performance in the RC. The predictions of the fractional and cumulative ash % of the product and reject streams have been compared with the published experimental results demonstrating a good agreement and thus, the robustness of the model.