Measurement and CFD Simulation of Liquid-Liquid Settling in Rare Earths Solvent Extraction Mixer-Settler

Mixer settler is widely applied in rare earths solvent extraction, the main ideas for the development of the settler is to achieve clean separation, reduce the loss of the reagents and the occupied areas. The hydrodynamics characteristics of settlers have been investigated in present work, both by experimental and numerical. Experiments that explored the influences of different parameters on the settling characteristic, such as impeller speed, volume flow of aqueous and organic phase, have been conducted by Particle Image Velocimetry (PIV). Meanwhile, a three dimensional CFD simulation that based on standard k-e turbulent model and Eulerian model has been developed to predict the flow characteristics of the settler, which is proved to be well consistent with experimental data. Preliminary explorations of new design with baffles were proposed by simulations. Compared with the non-baffle settler, the residence time distribution of settler with baffles indicates better phase separation. Undoubtedly, the hydrodynamics simulation offers an easier, cheaper and time-saving idea to realize better designs for settler.