Numerical simulation of multiple physical field and reduction reactions in ferronickel furnace
In order to studythe smelting process of 36 MW ferronickel submerged arc furnace, a three-dimensional transient multi-physical field model coupling reduction reaction was established. The model compiled the transport equations of electrothermal conversion,electromagnetic induction, magnetic field perturbation, and reduction reaction by utilizing the User-Defined Function (UDF), which was used to simulate the process of multiphase flow, heat transferand mass transfer. Besides, the change regular of multiple physical fields and the processes of metal oxide reduction at different times wereanalyzed. The result shows that the AC arc is affected by electromagnetic and high-frequency currents, resulting in significant skin effect and proximity effect. When the smelting time is from 10 to 40 minutes, the maximum Joule heat at the buttonof arc zones increases from 2.38 to 10.32 MW/m3 and the maximum magneticfield intensity increases from 0.00379 T to 0.01397 T. After 40 minutes of smelting, the nickel oxide underthe arc is basically reduced. Moreover, iron oxide is partially reduced, and themass fraction of the iron oxide decreases from 25.2% to 12.6%. Finally, the reduction rate of nickel-iron oxide increases non-linearly with the increase of smelting temperature.