The Multi-physics Numerical Simulation In Neodymium Molten Salt Electrolytic Cell Based On Comsol

Fluoride molten salt electrolysis is the main method for producing neodymium,it has the advantages of good quality,lower cost,high recovery rate,high current efficiency.The distribution of electric field,temperature field and flow field in electrolytic bath has a great significance on the groove optimization and the parameters of neodymium molten salt electrolysis process.Therefore,studying on the rare earth electrolysis cell numerical simulation of multi physical field,promoting the rare earth electrolysis cell structure improvement and reducing the molten salt electrolysis energy consumption,have an excellent theoretical significance and application value.The thesis was based on the field theory,heat transfer science theory and fluid theory,establishing the mathematical model of the electric field,thermal field and flow field in rare earth electrolytic cell.It was based on the simulation platform of Comsol,simulating calculation of electric field,thermal field and flow field in the molten salt electrolysis slot,revealing the influence laws of tank structure parameter changes to the distribution of different physical field in the molten salt electrolysis process,providing a theoretical basis for practical neodymium molten salt electrolysis production and the operation optimization.The main research contents and conclusions are as follows:1?On the principle of Maxwell,under the invariable current situation,the thesis established mathematical model on the electrolysis electric field of neodymium molten salt with 3k A electric current,investigating the influence of electrode insertion depth and electrode distance to the electric field characteristics,like the cell voltage and current density.The results showed that the cell voltage can be dropped by increasing the electrode insertion depth and decreasing the electrode distance.It has the benefit for reducing the power consumption,but the decrease of current density is not conducive to improving the production efficiency.So the thesis should have an overall consideration on the energy consumption and production capacity,adjusting the electrode insertion depth and electrode distance reasonably,in order to reduce the energy consumption of neodymium molten salt electrolysis unit.2?On the theory of heat transfer,the thesis established mathematical model on the electrolysis bath thermal field of molten salt,inspecting the effects of electrode insertion depth and electrode distance to the distribution of electrolytic tank temperature.The results showed that the longitudinal distribution of temperature in the electrolysis groove was first increased and then decreased from top to bottom,the transverse distribution has been declining all the time from cathode to anode.The main heat source of the electrolytic tank concentrated in the middle of the electrolytic tank. The temperature of groove melting was increasing with the increase of electrode insertion depth and the electrode distance.That is conducive to the mobility of the molten salt.But the exorbitant temperature will make the generation of metal dissolved and reduce the current efficiency.So the thesis should have an overall consideration on the mobility of the molten salt and current efficiency,controlling the electrode insertion depth and electrode distance appropriately,in order to maintain a suitable temperature for electrolysis.3?On the theory of fluid,the thesis established a mathematical model on the electrolysis tank flow field of the molten salt,studying the effects of electrode insertion depth and electrode distance to the distribution of the flow field in the electrolytic cell.The results showed that the flow rate of melt is related to the electrode depth and electrode distance in the groove.When the electrode insert depth increases and also the electrode distance decreases,the flow rate of melt increased.This is beneficial to balance the electrolyte composition and temperature.But when the velocity is too large,it is not conducive to the collection of rare earth,resulting in metal dissolution,decreasing the current efficiency.So the thesis should have an overall consideration on the uniform composition of melt and the current efficiency,in order to control the electrode depth and electrode distance in a proper range.4?Using software Comsol with finite element to research the electrolysis electric field,thermal field and flow field of molten salt neodymium in mathematics is feasible.The results of simulation and actual production data are consistent wonderfully,which is indicating that the established model can reflect the actual production of the molten salt electrolysis of neodymium accurately.