PhD position
Laboratoire de Génie Chimique, Toulouse, France
LULABAT Project
Application of the leaching attrition process to the recycling of lithium-ion battery cathode materials
Recruitement Completed
Keywords: metal recycling; battery recycling; hydrometallurgical processes; attrition-leaching process; chemical engineering
Context
In order to meet the ecological, economic and technological challenges required for the transition to a circular, competitive and environmentally-friendly economy, the French government has set up the priority research program and equipment (PEPR) entitled “Recycling, recyclability and reuse of materials[1]”. Launched in May 2023, this program focuses on five major families of materials used on a daily basis (plastics, composites, textiles, strategic metals and paper/cardboard), as well as on various sectors, including batteries. The LULABAT project, financed by this PEPR and bringing together several research teams, is dedicated to the recycling of lithium-ion batteries. The recycling of these batteries, used in portable electrical appliances and vehicles, is a key issue in the deployment of new low-carbon energy technologies.
In order to selectively recover the various valuable elements (Li, Co, Ni, Mn, graphite) making up these used batteries, and to prepare chemical compounds that can be used to manufacture new batteries, hydrometallurgical processes are needed in the recycling chain. The first stage of these hydrometallurgical processes consists in dissolving the powders produced by crushing the batteries in an acid medium, which constitutes the leaching stage. Subsequently, various separation techniques (selective precipitation, liquid-liquid extraction) are implemented for the selective recovery of these elements, followed by purification and transformation steps to produce the desired compounds.
Scientific objectives
The thesis project proposed by the Laboratoire de Génie Chimique de Toulouse (LGC) specifically concerns the leaching stage of battery powders. It is based on a type of reactor developed at LGC, which enables mechanical constraints to be imposed on the particles to be dissolved, acting in conjunction with the chemical dissolution reactions. The mechanical constraints are produced by the addition of millimetre-sized balls introduced into the leaching reactor enclosure, and cause fracturing and wear phenomena on the particles. This attrition-leaching reactor has already been applied to the solution treatment of various materials, such as magnesium silicates[2] and chalcopyrite ores[3].
The main objective of this thesis project is to study the options offered by the attrition-leaching reactor for the hydrometallurgical treatment of lithium-ion battery cathode materials. In particular, it aims to explore milder operating conditions (moderate pH, wide range of Eh potentials), which are more selective and enable leaching reactions to be adjusted to subsequent separation stages. In addition, this project aims to gain a deeper understanding of the effect of certain attrition-leaching process parameters (e.g. size and quantity of grinding media) on mechanical stresses (attrition, fracturing, mechanical activation) and their impact on dissolution mechanisms.
The methodology will combine experimental testing in a dedicated reactor, characterization of the solid and aqueous phases using complementary techniques (e.g. microscopy, X-ray diffraction, chemical analysis, particle size analysis) and equilibrium calculations using thermodynamic software. Modeling of the attrition-leaching process in this context, coupling a physical model of attrition and leaching with a thermodynamic model, is also envisaged.
Professional environment
The thesis will be carried out at the Laboratoire de Génie Chimique[4], located in Toulouse, France, which is a joint research unit between the Institut National Polytechnique de Toulouse, the Université Paul Sabatier and the Centre National de la Recherche Scientifique. The laboratory's research, carried out by 300 staff in 6 research departments, is largely conducted within the framework of a network of academic and industrial collaborations, with around 30 doctoral theses defended each year.
The doctoral student will be enrolled in the MEGEP doctoral school (Mechanics, Energy, Civil Engineering, Processes). He or she will be employed by INP-SAIC, via a 36-month doctoral contract financed by the LULABAT program. As part of this project, the PhD student will interact with other PhD students working on related projects (at CEA-LITEN in Grenoble, at LRGP in Nancy), and take part in project progress meetings. At LGC, the PhD student will be integrated into the IRPI department[5], and more specifically into the team which has been developing this type of approach for several years, in the context of various hydrometallurgical processes.
The thesis will be co-directed by Laurent Cassayre (CNRS Research Director) and Florent Bourgeois (Professor at Ensiacet).
Profile and skills required
Candidates must have a MSc with an initial research experience. The proposed subject requires above all a taste for experimentation and process development. The candidate should have a solid background in physical chemistry, aqueous solution chemistry and chemical engineering. Knowledge of materials characterization techniques, solution analysis and/or process thermodynamics will be an asset.
To apply
The deadline for application is July 20, 2023. Applications should be sent to the following address: Cette adresse e-mail est protégée contre les robots spammeurs. Vous devez activer le JavaScript pour la visualiser.
The application (in the form of a single pdf file) must contain the following information:
- Summary CV, including current professional situation and qualifications,
- Academic background and transcripts,
- Research internship topic and supervisor's letter of appreciation,
- English language skills,
- Motivation letter demonstrating the suitability of the candidate's profile to the proposed subject.
[1] https://premc.org/pepr-recyclage/
[2] https://www.frontiersin.org/articles/10.3389/fclim.2022.946735
