Computational modelling of non-dispersive solvent extraction of uranium in hollow fiber contactor operated in recycle mode

Abstract

Extraction of uranium and acidity by using TBP (tri-n-butyl phosphate)-n-dodecane through hollow fiber contactor operated in the Non-Dispersive Solvent Extraction (NDSX) configuration with recycle mode is simulated by using a two-dimensional axisymmetric multi-component Computational Fluid Dynamics (CFD) model. This multi-component model solves continuity and momentum transport equations for the feed and shell sides and solute transport equation for the feed side, shell side as well as for the membrane phase. Complex boundary conditions of flux continuity and concentration jump are implemented in the model. Recycle mode of operation is simulated by solving the differential equations representing transient mass balance for feed and solvent reservoirs bottles simultaneously with the governing equations of the CFD model. Validation of the model has been done by comparing predicted and experimentally measured percentage extraction of uranium and nitric acid for different parametric conditions. The validated model has been used to have detailed insights into the spatial and temporal variation of concentration and flux profiles inside the contactor. The CFD model of hollow fiber contactor, which is widely accepted as a separation process intensification tool, will be useful for optimization of the design, operation and scale-up.