Simulation of ferrochrome settling behavior in a submerged arc furnace using a multiphysics and multiphase model

The ferrochrome settling behavior significantly affects the smelting performance of a submerged arc furnace. This paper presents a three-dimensional (3D) transient mathematical model simulating the complex multiphase flow and thermochemical phenomena inside an industrial furnace. Via the model, the smelting phenomena are clarified in terms of electromagnetic field, temperature distribution, multiphase flows, and ferrochrome productivity. The effects of phase voltage varying from 75 to 85 V are quantified as well. Furthermore, the interface among the furnace burden, slag, and ferrochrome is used to characterize the ferrochrome settling behavior. The results show that the real-time reduction reactions determine the location and output of ferrochrome droplets. As the phase voltage increases, the current increases by 13.06 pct, the ratio of voltage drop between the furnace burden and submerged arc increases by 0.17 pct. The path of ferrochrome droplets affects the high temperature zone, which is the largest at a phase voltage of 85 V. At this phase voltage, the droplet velocity is the highest and the ferrochrome output is 6.86 t/h. Correspondingly, the energy consumption is 3363.81 kWh/t and the content of Cr is 57.09 pct. The results in the present study can be employed for decision-making on improving the operation of submerged arc furnaces to reduce the energy consumption and improve ferrochrome quality.