Abstract:Solvent extraction is widely used in hydrometallurgical solution purification and non-ferrous metal extraction, and is also the main means of beryllium solution purification. Mixing and clarification of extraction tanks due to good performance and operability in the industry has been widely used, and its structure consists of mixing and clarification of the chamber. The degree of mass transfer within the mixing chamber directly affects the number of extraction stages and equipment size used in this process. Solvent extraction of beryllium solution is a typical liquid-liquid two-phase flow process, with the aqueous and oil phases acting as the dispersed and continuous phases, respectively. Improving the two-phase flow field is an effective way to enhance droplet breakup and mass transfer, but it is currently difficult to experimentally measure parameters such as turbulent dissipation and shear in the flow field. With the continuous development and improvement of CFD (Computational Fluid Dynamics) technology, the reliability of its analytical results has been continuously verified, and the use of computer technology has become an important means of industrial design and production. In order to study the flow characteristics of liquid (aqueous phase)-liquid (organic phase P204) two-phase fluid in the mixing chamber of beryllium solution extraction process in the stirring environment, two fluid model (TFM) combined with the moving reference system technology was adopted to realize the simulation of beryllium solution extraction process. The two-phase fluid was regarded as a continuous medium by TFM, and can solve the mass and momentum conservation equations respectively, which can take into account the accuracy and reliability. TFM has been successfully applied to the simulation of gas-solid, liquid-liquid, liquid-solid, and other multiphase systems, taking into account both accuracy and computational efficiency. The effects of baffles on the velocity, turbulent kinetic energy, turbulent dissipation rate and shear rate inside the mixing chamber were investigated, and the model was solved based on the commercial fluid dynamics simulation software Ansys Fluent 2024R1, which provides theoretical references to understand the mixing characteristics of liquid-liquid two-phase flow by baffles, and further optimize the design. The results show that the solvent extraction of beryllium solution can be realized based on the mixing and clarification tank. By adding baffles in the mixing chamber to improve the two-phase flow field, the solutes in the mixing chamber can diffuse in time, reduce the dead zone and increase the reaction rate. The maximum turbulent kinetic energy in the mixing chamber is increased by 0.95×10-2 m2/s2, and the maximum turbulent dissipation rate in the mixing chamber with the baffles reaches two times of that in the case of the mixing chamber without baffles. The solute mixing can be made more homogeneous and the droplet fragmentation can be more adequate, so that both the mass transfer area and the mass transfer rate can be improved. The extraction time is shortened from 20 minutes to 12 minutes. In practical application, it can be considered as an effective means to strengthen droplet fragmentation and mass transfer.