Research On The Flow Field In The Rare Earth Electrolysis Cell By Numerical Simulation And The Calculation Of The Molten Salt Thermal Conductivity

With the development of the market, saving energy and reducing consumption for rare earth metallurgy industry can increase its market competitiveness. For the rare earth electrolysis cell, reducing its energy consumption means reducing the cost of the product and increasing its competitiveness in the market. There exists complex physical field in the electrolytic cell,while the study of the flow field is the basis of understanding other physical field, and the determination of thermal conductivity is a prerequisite to study the temperature field. In this article, based on the 3KA rare earth electrolysis cell, multi-phase flow, free-surface liquid motions in the electrolytic cell, neodymium sinking rule and the best time to take metals are researched by numerical simulation. Moreover, the thermal conductivity of molten salt electrolyte in different temperature is calculated through the theoretical derivation. These results will provide the theoretical base for the design of electrolysis cell and Energy-saving and Consumption-reducing.Firstly, simulates the flow field of the three different field distribution and surface downstream fluctuations using the CFD software. Through analyzing the effect of single-phase and multiphase on flow field in the cell,draw the anode gas is mainly distributed in between anode and cathode near the inside surface of the area, the 0.03 meter near the anode in the surface, the more severe melt body fluids surface wave, slope height to 0.15 meter,anode gas floating is the main impetus of the electrolyte flow between the anode and cathode, which is also the main reason for the electrolyte's surface wave. Moreover, neodymium liquid's sinking is the main driving force of electrolyte movement in the lower half of cell. The conclusion satisfies the condition of flow in the practical production, which lays a foundation for theoretical studies on fluid flow in the cell.Secondly, the sinking and diffusion rule of Neodymium liquid in the cell after formation on the cathode are simulated. This study finds that the Neodymium liquid drops down in the small round droplets when it gatheres to a certain degree under the cathode. After dropping to the cell bottom, these round droplets do not gather under the cathode, but sprinkle around the crucible first, then gradually concentrate the crucible's center. The spreading regions and concentration of neodymium between the poles increases with the increasing of time, and neodymium becomes closer and closer to the anode. With further analysis of the current market conditions, the best time to take metals is determined which is electrolyzing for 3.5 hours. Finally, based on the calculation principle of thermal conductivity of the mixed molten salt, the thermal conductivity of the one-component molten salt in the rare earth electrolytic cell was caculated. Thus the thermal conductivity of ternary system molten salt electrolyte can be predicted. The study finds that the thermal conductivity of ternary system molten salt electrolyte calculated by the modified power-law relationship of the mixture thermal conductivity has higher accuracy. In temperature to 973 - 1373K, for the plasma-nitriding 85. 8%NdF₃ - 10.7%LiF-3.5%Nd₂O₃system varing with temperature are mainly distributed in the main 0. 7- 0.85W (m·K),which could provide an important physical parameters for the research of the temperature field in the rare earth electrolytic cell.As a applied basic research, this topic has a strong pertinence and practical.It is significance not only lies in the theoretical exploration and the innovation of production practice, but also provides theoretical basis for the practical production.