Simulation Study on the Carbon Particles Trajectories in an 8 kA Rare-earth Molten Salt Electrolytic Cell

During the rare-earth molten salt electrolysis process, the graphite anode can release carbon particles into molten salt, forming impurities. Upon contact with rare earth metals, these impurities can adversely affect metal purity and overall product quality. This study focuses on an 8 kA rare-earth electrolytic cell and employs Ansys Fluent software to simulate the motion trajectories of carbon particles with varying particle sizes and different detachment positions on the inner surface of the anode. The calculation results demonstrate that the trajectory of carbon particles is mainly influenced by drag force buoyancy and gravity, with drag force being the main factor affecting the trajectory of particles. The degree to which carbon particles are influenced by drag force is correlated with their particle size: larger particles experience a more pronounced drag force effect. Shed carbon particles tend to migrate toward the cathode within the electrolytic cell. Increasing the inter-electrode distance can effectively inhibit the migration of carbon particles toward the cathode. Therefore, the movement behavior of carbon particles should be considered when designing rare-earth molten salt electrolytic cells and selecting graphite materials.