Improving metals recovery in catalysts: Advanced modelling of leaching in porous structures

Context: Currently, only 10-20% of end-of-life catalysts are recycled after their use in refineries. However, these catalysts contain critical metals (Ni, Co) and the management of these resources is becoming increasingly constrained and regulated. This makes catalyst recycling a major environmental and economic challenge. Hydrometallurgy is today a key process for recycling metals. Leaching, which consists of dissolving the metals in an aqueous acid solution, is the step that needs to be carefully optimized in order to increase metal recovery, to reduce the amount of solvent used and, in the case of hydrotreating catalysts, to avoid damaging the alumina support. This would make it possible to offer a short-loop recycling process by reusing the leachate and the support to produce new catalysts. In this context, the aim of this Ph.D. thesis is to develop a methodology for modelling catalyst leaching stages on complex porous structures.
Description: At present, the leaching process has not been optimized to achieve its optimal performance, and this work is complex because it depends on the metals present and on their interaction with the support. The first phase of the work will therefore involve the acquisition of the experimental data required to model (solubility, desorption kinetics, support characterization, etc.) and to evaluate the effect of operating conditions on leaching performances. These experiments will be supported by detailed analytical characterizations. The reaction scheme will then be constructed, validated, and extrapolated to assess its robustness. The second part will consist of the development of a 1D model integrating the leaching kinetics and a first approach to account for the influence of the pore network using a tortuosity factor. Finally, the descriptors of a 3D model with a complete pore network representative of a hydrotreating catalyst will be proposed based on the data obtained during the thesis.

Keywords: metal recycling, porous structures, modelling

• Academic and IFPEN supervisor    Dr Clémence NIKITINE, Ingénieure de recherche, IFPEN, ORCID : 0000-0003-2642-4349
• Doctoral School    ED206 chimie, procédés, environnement, Université Lyon
• PhD location    IFP Energies Nouvelles, Lyon, France
• Duration and start date    3 years, starting in the fourth quarter 2025 (Novembre 3)
• Employer    IFP Energies Nouvelles
• Academic requirements    
  • University master’s degree in chemical engineering 
  • Language requirements    English level B2 (CEFR), French level B1
  • Other requirements    Experimental and modelling knowledge, knowledge of a programming language is required, Skills in materials characterization would be an asset

To apply, please send your cover letter and CV to the IFPEN supervisor indicated here below.