Simulations were performed under continuous processing conditions using the 2D continuum model to describe the internal state of a multi-solid system comprising solid particles of different sizes and densities at the same time. The feed consisted of 35 types of solid particle species with five different sizes, 1.70, 1.20, 0.85, 0.60 and 0.35 mm and seven different densities ranging 1400 to 2000 kg/m3. The simulations results have been used to plot the concentration profiles of solid particles along the bed height. The concentration profiles of the solid particles depicted that the fine dense particles, 0.60 mm, having density equal to 1900 kg/m3 and terminal velocity 0.058 m/s moved downwards and discharged into the underflow. However, the low-density coarse particles, 1.20 mm, having density equal to 1400 kg/m3 and terminal velocity 0.068 m/s moved upwards and conveyed to the overflow, hence, showing a separation process based on the density difference. Furthermore, simulation results showed that the particle species having densities close to the value of the separation relative density exhibited higher concentrations along the system height and the suspension within the system was mainly composed of these species.

This study focusses on the description of the internal state of a modified fluidized bed separator also known as the Reflux Classifier. The device is a high-performance beneficiating technology employed in many mineral and coal processing industries. A 2D continuum model was used to examine the transport behavior of solid particles within the Reflux Classifier for a multicomponent mixture under continuous operating conditions. Three different types of feeds comprising solid particles of size ranging 49 to 421 µm and densities equal to 1400, 2490 and 5000 kg/m 3 were simulated simultaneously under identical process conditions. The feed flux and fluidization velocity were kept at 0.0037 m 3 /m 2 s and 0.022 m/s, respectively. A comparison of the simulation results showed that the value of separation size shifted towards lower values, 340, 181 and 90 µm, when the density of the feed was changed from 1400 to 2490 and 5000 kg/m 3 , respectively. The data generated through simulations was used to demonstrate the movement of solid particle within the inclined section by plotting net flux of the solid particles across the inclined channel width. It was observed that the net flux of finer solid particles was higher than the coarser ones within the inclined section.