Numerical Simulation And Application In Rare Earth Extraction Dimensional Flow Field And Mixing Process

Mixing equipments are widely used in the extraction processes of Rare earth. The mixingeffect of feed liquid in agitation tank has a direct influence on the extraction of Rare earthelement. The nature of mixed movement generated by feed liquid in agitation tank is a complexturbulent flow. There are many scholars use the experimental methods and numerical simulationmethods to study the flow field and mixing process of fluid (especially when the fluid flow isturbulent flow) in agitation tank. Compared with the two methods, the study period of numericalsimulation is shorter and it can get more data.The mixing characteristics of dual and three layer impellers in the agitation tank was studiedrespectively by using numerical simulation package FLUENT. The multi-reference frame (MRF)and standard k turbulent model were used in the simulation. The mainly studies were asfollows:Keeping the revolving speed and insertion depth of dual layer impeller unchanging. And theinfluence of interlayer spacing on the speed field and turbulent kinetic energy was studied in thesimulation. When interlayer spacing is less than the oar’s diameter, the flow generated by the twoimpellers has good communication and the mixing effect is good. If interlayer spacing is greaterthan the oar’s diameter, the interaction of two impellers becomes weakened obviously and twoimpellers form their own cycles, and the flow field has zoning. The mixing effect is bad too. Sothe two impellers should have a best interlayer spacing.The mixing process of dual layer impeller with different interlayer spacing was studied onthe basis of the simulation of flow field. The diffusion process of tracer in agitation tank wasanalyzed. And the mixing time of different interlayer spacing was got. The optimal interlayerspacing was determined by mixing time.The three dimensional flow fields of three layer impellers in the agitation tank were studiedby numerical simulation when the revolving speed was unchanging. The characteristics ofvelocity field and pressure field and the influence law of negative pressure in import on differentinsertion depth were analyzed. The optimal insertion depth corresponding to the maximumnegative pressure in import was got.The research results in the paper provide guidance for the optimized design and installationof the mixing equipment.