TBP-Diluent-H_2O-HNO_3 Solvent Extraction

Report Revision on 15 November 2025

TBP-Diluent-H\(_2\)O-HNO\(_3\) Solvent Extraction#

Stage is a Cortix module developed at Cortix Tech to model and simulate system-level physicochemical phenomena in a single stage of a solvent extraction contactor process. This module integrates into the Cortix architecture of network dynamics HPC simulation and can be coupled with many other instances to model a contactor bank in future developments of this project. Therefore the module and simulation tool design followed here applies to a multi-stage process and it is based on a network dynamics simulation as described in Cortix.

The focus of this document is to describe the development of the stand-alone Stage which is aimed at providing superior modularity and flexibility to account for all possible scenarios of interest to the user when modeling and simulating uranium solvent extraction processes. Therefore Stage has been developed for any chemical reaction mechanism. The modularity for reaction mechanisms is provided by Cortix.

Elements#

The concerns of Stage are to

  • Implement the mixing and disengagement of immiscible phases,

  • Apply balance laws and thermodynamic constitutive constraints,

  • Build the system of governing equations, and

  • Solve the resulting time-dependent, coupled, non-linear, stiff (algebraic) ordinary differential equations.

Stage considers 3 phases, namely organic, aqueous, and vapor. If one phase is neglected, it appears as an empty Cortix phase container. There are great differences in the way disengagement occurs in contactors in practice, therefore a central design and implementation of Stage is to handle all practical types of mixing and disengagement. Currently both mixing and disengagement are of type: instantaneous.

The flows of the organic and aqueous phases are always countercurrent to each other, however at this moment it is unknown the direction of the vapor phase, therefore it is assumed each of the aqueous and organic phases drag the vapor phase. Hence the vapor flow is cocurrent to other phases. This assumption will be revisited once collaboration with experimental colleagues takes place.

_images/contactor.png

_images/solvex-module.png

Solvex Contactor Sketch

Solvex Module Diagram

Stage Cortix module source

Development Path#

The Stage module is being developed in a progression of usecases:

  1. Water-air contact (empty organic phase)

  2. Water extraction in TBP/n-dodecane (w/o and w/ air)

  3. Aqueous nitric acid extraction in TBP/n-dodecane (w/o and w/ air)

  4. Uranyl nitrate, nitric acid, water extraction in TBP/n-dodecane (w/o and w/ air)

  5. Metal impurities, uranyl nitrate, nitric acid, water extraction in TBP/n-dodecane (w/o and w/ air)

aimed at elucidating many aspects of the modeling and simulation of solvent extraction of interest to the user. Each of the usecases will be individually studied and documented starting with the current case through the use of reproducible electronic notebooks.

Participants at Cortix Tech#

  • Dr. Valmor F. de Almeida, Techical Lead, is the principal developer of Cortix and derived modules including Stage. He leads the coding efforts at Cortix Tech.

  • Viggo F. de Almeida, BS student in Nuclear Engineering, U of Tennessee Knoxville, is the maintainer of the website for usecases testing and documentation.

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