CFD–DEM modeling of particle segregation behavior in a simulated flash smelting furnace

Particle behavior plays a crucial role in flash smelting furnaces, but limited understanding is hindering further development of this modern pyrometallurgical process. This study presents a two-way coupled CFD–DEM approach to investigate particle distribution, collision, and segregation behaviors within a furnace. The simulation results are validated against experimental data, demonstrating good agreement. The effects of the particle mass–flow rate and size distribution are then analyzed. The results indicate that small particles are carried by airflows to the center of the particle-dense region, whereas large particles remain at the outer part, worsening segregation. Increasing the mass–flow rate significantly increases the particle number density and number of particle collisions but barely influences size-induced segregation. In contrast, enlarging the size of fed particles reduces particle number density and broadens dense distribution within a safe range. This ensures the necessary space and high mixing index of the particles, which benefits high-rate smelting processes.