Simulation Research On Electromagnetic Stirring Electrolysis In Rare Earth Electrolytic Cell

With the growing demand for rare earth metals and their alloys,the equipment for the preparation of rare earth metals and alloys is further optimized to improve the electrolysis efficiency.To research on the scale of change of excessive flow velocity and the existence of flow dead zone in the rare earth electrolytic tank,the electrochemical mathematical model is used to simulate the overall flow field change in the 8k A rare earth electrolytic tank,and the electromagnetic field simulation and electromagnetic stirring simulation are carried out by adding coils at different positions of the electrolytic tank.The maximum flow rate of the electrochemical flow field was used as a reference for the flow field regulation under electromagnetic stirring,so that the fluctuation of the flow rate in the tank could be maintained stable during the electrolysis to improve the electrolysis efficiency,and the position of the added coils for electromagnetic stirring and the size of the current waveform and ampere-turns passed into the tank were determined.The specific findings of the study are as follows:(1)A mathematical model of the flow field and electrochemistry of the rare earth electrolytic tank was established,and a three-dimensional simulation research on the electrochemical transient in the tank was carried out for 12 minutes at the time of charging as the initial time,and the maximum flow velocity in the tank was analyzed to obtain the required flow velocity of 1.5m/s in the electromagnetic stirred tank.The analysis of the flow field in each area of the tank showed that the main flow pattern was upward in the inner anode area,where the flow velocity was often at the maximum,downward in the cathode area,where the flow velocity was second,and the longitudinal vortex formed in the area between the anode and the cathode,where the flow velocity was less than the first two.The outer anode area is the dead zone with the lowest flow velocity,and the crucible collection area tends to be stable with a much lower flow velocity than the inner anode and cathode areas.(2)A mathematical model of the electromagnetic field of the rare earth electrolytic cell is established,and a three-dimensional simulation of the time-varying induced electromagnetic field under 1 Hz sine wave and square wave currents is carried out for different locations of the electrolytic cell to simulate the electromagnetic force analysis.The magnitude of the electromagnetic force decreases from the middle section of the coil to the outside.(3)Based on the simulation and analysis of the induced electromagnetic field,the three-dimensional simulation and analysis of the time-varying electromagnetic stirring with the addition of coils at the top,bottom and side of the electrolyzer were carried out,and it was found that the electromagnetic stirring could not be carried out with the coils at the bottom of the side.Based on the maximum flow rate in the electrolysis process,the analysis of electromagnetic stirring under flow field regulation shows that the stability of the flow field is better with the addition of coils above the side of the electrolyzer than at the bottom,and the flow field changes steadily under electromagnetic stirring,which effectively drives the electrolyte in the flow dead zone of the electrolyzer.Combined with the required flow rate in the electrochemical flow field analysis,the position of the added coil for electromagnetic stirring in the rare earth electrolytic tank was determined to be above the side,the current waveform was sine wave,and the required number of AN turns was 3000.The above research shows that the electromagnetic stirring with an external coil can effectively regulate the flow rate in the rare-earth electrolyzer,solve the flow dead zone problem and improve the electrolysis efficiency,which is of certain reference value for the optimization of rare-earth electrolyzer.