Interview with Pierre FEYDI, Research Engineer in Chemistry and Chemical Engineering and Richard LAUCOURNET, Materials Formulation Laboratory Manager at CEA.
- The extracted metals will be used to manufacture new NiMH batteries, optical lenses, lamps, glass additives or capacitors, among other components
The Atomic Energy and Alternative Energies Commission (CEA) is leading RESLAG’s Pilot 1, which focuses on black foundry slag as a raw material for extracting high value-added metals. This pilot project addresses a new methodology based on selective hydrometallurgy. CEA shares with us the progress of these tasks, as well as the expectations for the remaining months of the project.
QUESTION. How did the rehearsals and demonstrations go?
ANSWER. The extraction of high value added metals was initially planned to be carried out on black foundry slag. In spite the slags analysed in the project showing the absence of such elements in significant concentration (>1%wt), it was decided to make the demonstration using the slag generated in the NiMH batteries smelter, which are rich in Rare Earth Elements (REEs) (>5%wt).
The melting and the mechanical treatment of rich REEs slag are already completed. Currently, the focus is pointed out on the chemical part (Leaching, Separation by SMB, Precipitation of REE’s). The demonstration of chemical extraction is currently in progress.
Q. What are your expectations for the remaining months of the project?
A. We expect to finalize the global treatment of the slag (Melting, Mechanical and mostly chemical treatment). We want to measure the purity of the recovered products and obtain values regarding the chemical reactants consumption and the efficiency of the global process.
The final demonstration will be carried out by processing in continuous the SMB equipment (SMB = Simulated Moving Bed. It is a highly engineered process for implementing chromatographic separation) during two days.
Q. What have been the main difficulties you have faced in this Pilot?
A. The main difficulty we faced was the identification of a slag with enough concentration in critical elements to define the Pilot 1 process, mainly the chemical separation and the extraction of high added value element (here the rare earth elements). It caused a 6 months delay on the initial planning.
Q. What practical applications will the recovery of high value added metal slag have? What can these metals be used for?
A. We mainly recover Lanthanum, Cerium and Neodymium. These metals can be valorised as:
1) Mixed rare earth oxides (REO) in:
- Petroleum cracking catalyst
- Mischmetal lighter flints
- Polishing compounds
- New NiMH batteries
- Optical lenses
- Host for phosphors fluorescent lamps
- Ce-stabilized ZrO2 structural ceramics
- Glass additives
- New Nd2Fe14B permanent magnets
- Laser glass
- Metal halide lamps
Q. What is your general assessment of the RESLAG Project?
A. Through the Pilot 1, we have evaluated the Separation by SMB chromatography compared to more classical hydrometallurgical techniques of separation such as liquid-liquid extraction or selective precipitation. Now from this first demonstration, other wastes will be soon considered as good candidates for this technology, such as used Li-ion batteries with the extraction of Ni and Co.
In general: expanding the network of partners; new opportunities for the valorisation of slag (economic aspects to be confirmed); implementation of a network for the valorisation of slags between slag producer, formulator/manufacturer (Optimum Cement and CEA), ceramic industry for the sintering (subcontractor: CTI: Céramiques Techniques Industrielles) and end-user (DLR).
Q. What is your assessment of the European policies outlined in recent years that have set the reduction of energy consumption and of waste generation in industrial processes as a strategic objective?
A. CEA is a Research and Technology Organization which promotes a sustainable development of new technologies for energy.The reduction of energy consumption and the reduction or the valorisation of waste are considered as a key drivers in most of the project. The current strategy of materials development is in agreement with European policies aiming a strong reduction of waste and going to zero waste.