Title Promoter Affiliations Abstract "Extraction of Rare Earths." "Koen Binnemans" "Sustainable Chemistry for Metals and Molecules, Process Engineering for Sustainable Systems Section, Sustainable Metals Processing and Recycling" "The rare earths are a group of 17 elements in the periodic system, including neodymium (Nd), europium (Eu), terbium (Tb), dysprosium (Dy) and yttrium (Y). These elements are becoming more and more important, because of their essential role in permanent magnets, lamp phosphors, catalysts and rechargeable batteries. The rare earths occur in Nature as mixtures and these mixtures are difficult to separate due to the similar chemical properties of the rare earths. This project is about new approaches for the concentration and separation of rare-earth elements, and their transformation into metallic form, starting from rare-earth slags or recycled rare- earth concentrates. These processes can be described under the general name of extraction of rare earths.The problem of dispersion of the rare earths in oxide slags will be solved by concentrating the rare earths in rare-earth-rich phases formed by addition of fluorine or phosphorus compounds to molten slags. New separation methods will be developed. These include photochemical oxidation or reduction of rare earths, and separation of rare-earth ions in strong magnetic fields." "Research Platform for the Advanced Recycling and Reuse of Rare Earths (RARE³)." "Koen Binnemans" "Sustainable Chemistry for Metals and Molecules, Process Engineering for Sustainable Systems Section, Department of Materials Engineering, Research Centre for Economics and Corporate Sustainability, Brussels Campus, Surface and Interface Engineered Materials, Sustainable Metals Processing and Recycling" "To contribute to the transition towards low-carbon, closed-loop economies the recycling of rare earths (REEs) will be crucial. Currently, End-of-Life recycling rates for REEs are less than 1%. RARE³ targets to develop recycling flow sheets to recover the five critical rare-earth elements (Nd, Eu, Tb, Dy, Y) from phosphors and magnets, being the two economically most important REE containing postconsumer streams. More efficient, direct and environmentally benign separation methods are targeted as well. Consequential LCA and economic modelling will be used to gain insights in the different scenarios for the global rare earth material flows and their environmental impact, which will lead to recommendations for decision makers (within companies) which technologies to implement and stimulate and how to secure REE availability in the EU. RARE³ is structurally embedded in the flagship SIM² research line at KU Leuven and features a User Committee consisting of all major REE players in the EU and the US." "Site selective spectroscopy of rare earth doped luminescent materials" "Dirk Poelman" "Department of Solid State Sciences" "Through a combination of site selective spectroscopy (x-ray absorption, electron paramagnetic resonance and luminescence spectroscopy), rare earth doped luminescent materials are investigated. Combined with structural research, this yields information on the exact surroundings of the rare earths. Since the luminescent properties are strongly dependent on this, the research is also important for potential applications." "Spectroscopic examination of rare earth ions in solids with a large band gap with the aid of magnetic resonance, optical techniques and Density Functional Theory" "Freddy Callens" "Department of Solid State Sciences" "In this project the structural and optical properties of fluoride crystals and wide band gap semiconductors, doped with paramagnetic rare earth ions, investigated." "Development and optimization of X-ray spectroscopic methods for the analysis of rare earth elements in geological materials." "Laszlo Vincze" "Department of Chemistry" "The research is focused on developing and optimizing methods for the analysis of REEs in geological materials, including samples returned by the Hayabusa2 and OSIRIS-REx missions. These nondestructive methods include wavelength dispersive detection setups for REE L-line excitation between 4-8 keV, and high-energetic incident beam XRF for K-line excitation between 30-54 keV with an incident beam energy of 90 keV." "Development and optimization of X-ray based analytical techniques towards the analysis of rare extraterrestrial materials." "Laszlo Vincze" "Department of Chemistry" "Micro-XRF spectroscopy, using synchrotron or conventional X-ray source based excitation, is a well-established non-destructive, microanalytical method, providing information on the elemental distributions in the probed sample. When three dimensional spatially resolved information is of interest, often a confocal micro-XRF detection scheme is applied as an alternative to XRF tomography. However, both methods pose significant challenges when attempting to quantify this data. This proposal aims the further development of quantitative 3D confocal XRF and XAS techniques for the detailed non-destructive and contamination free study of rare-earth element and heavy metal compositional information of unique extraterrestrial materials, acquired from a.o. the prestigious JAXA Hayabusa2 space mission. The project will focus on a) the development of a lab based XAS/XES instrument, as well as b) further developing 3D structural analysis by means of state-of-the-art full-field XAS and inelastic X-ray scattering methodologies. The experimental studies will be performed as a member of the Hayabusa2 analysis team, in close collaboration with the NanoGeoscience group lead by Prof. F.E. Brenker (Johann Wolfgang Goethe-University, Frankfurt, Germany). Currently approved research projects include: at the P06 Hard X-ray Micro/Nanoprobe at the PETRA III (Hamburg, Germany) and DUBBLE beamline (BM26 and BM14) at the ESRF (Grenoble, France) synchrotron radiation facilities." "Magnetomobility of Paramagnetic Ions and Solution Droplets" "Jan Fransaer" "Sustainable Chemistry for Metals and Molecules, Surface and Interface Engineered Materials" "Separation of rare earth ions with strong magnetic fieldsRare earths elements (REEs) are a group of 17 elements in the periodic table, including the 15 lanthanides, scandium and yttrium. These elements are today critical because of their essential role in applications such as permanent magnets, lamp phosphors, catalysts, rechargeable batteries, etc. They occur in nature as mixtures and are very difficult to separate into the individual elements due to almost identical chemical properties. Traditional separation methods, based of chemical properties, demand fastidious steps and are not environmental friendly. Our objective is to explore magnetic properties of individual rare earth ions ions (paramagnetic - attracted to a magnetic field; and diamagnetic - repelled by a magnetic field) to develop an unconventional process of separation. During the 50’s, Noddack et al. obtained a partial separation of rare earth ions, however there is not much more literature on the separation of these elements.For the instance,  we obtained interesting results showing the magneto-migration of paramagnetic ions (ex.: dysprosium) towards the surface of a magnet (NdFeB) and the diamagnetic ions (ex.: yttrium) moving in the opposite direction of the magnet surface. A more complex scenario seems to take place when mixtures of paramagnetic and diamagnetic ions are exposed to a magnetic field gradient. Opposite to the expected, both ions migrate together in the direction of the magnetic field. It can be can be assumed as a strong indication that rare earth ions do not behave as individual ions when in solution and submitted to a magnetic field. Instead, a cooperative effect seems to exist and research is still need to understand this behavior. Even the fact rare-earth ions in solution are influenced by a magnetic field is already a counter intuitive observation. Theory predicts that rare-earth ions are too small to be influenced by external magnetic fields and results with these observations are very challenging to explain and demand deeper explanations." "Optical spectroscopy of rare-earth (lanthanide) ions doped iparent nano-glass-ceramics with application to plasmonic and meta-materio-structures." "Victor Moshchalkov" "Quantum Solid State Physics (QSP), Department of Chemistry" "We have prepared transparent nano-glass-ceramics 32(SiO2)9(AlO1.5)31.5(CdF2)18.5(PbF2)5.5(ZnF2):3.5(ReF3) mol%, single doped with different rare-earth ions (Re), such as Er3+, Eu3+, Ho3+, Dy3+, Tm3+, and co-doped with Yb3+-Er3+-Tm3+, Yb3+-Er3+-Ho3+ and Yb3+-Er3+. In this nano-glass-ceramics, the rare-earth dopants are incorporated in tiny crystalline nano-particles PbF2 of about 8 nm diameter as evidenced by means of X-ray diffraction (XRD) patterns and high resolution transmission electron microscopy (HR TEM). We have found that our transparent rare-earth doped nano-glass-ceramics have advanced photo-luminescence properties, which overcome other materials known to date, in particular for luminescence at telecommunications wavelengths near to 1.5 µm and for up-conversion luminescence. We investigate interaction of radiation from nano-particles in our rare-earth doped nano-glass-ceramics with plasmon-polariton waves in nanostructured metals and with resulting meta-materials." REBIKE "Koen Binnemans" "Sustainable Chemistry for Metals and Molecules" "In recent years the supply of certain materials has come under increasing supply constraints as outlined in the EU critical materials list. The rare-earth elements top this list, and within the rare-earth category, Nd and Dy are singled out due to their important role in the manufacture of rare-earth permanent magnets (based on an alloy of NdFeB with additions of Dy). NdFeB magnets are used in a diverse range of products including for example computers, loudspeakers, automotive applications, and electrically power assisted bikes (EPACs). In a recent report by the ERECON consortium (European Rare Earth Competency Network) EPACs were highlighted in particular as a potential source for NdFeB magnets which should be recycled. In order to provide power to the electric motors, EPACs also utilise either nickel metal hydride or lithium ion batteries. Li is very close to being highlighted on the critical materials list in part due to the rapid expansion of the battery sector across the globe. At end-of-life the Li-ion batteries are not only a potentially valuable resource for the EU in terms of Li collection, but they are also a large potential hazard due to the flammability of the organic electrolytes contained within them. The aim of REBIKE is to develop novel extraction and recycling technologies for both permanent magnet motors, and Li-ion batteries used on EPACs in order to provide a sustainable supply of some of the most critical elements to the EU. The REBIKE consortium aims to involve all relevant stakeholders along the EPAC value chain covering experimental and modelling capabilities. Besides underpinning a major emerging industrial sector, this project will facilitate the pivotal role played by EPACs in realising EU ambitions to cut CO2 emissions and lead to major impacts on health, employment, environment and social policy." "Recovery of scandium, yttrium and lanthanides from bauxite residue using solvent extraction with ionic liquids." "Koen Binnemans" "Sustainable Chemistry for Metals and Molecules" "Secondary resources are essential to maintain the supply of critical metals in our fast-developing society. Recovery of metals from waste materials is not only important to meet the increasing demand, but also in view of a sustainable future for our planet. The rare-earth elements are listed as critical metals by the European Commission because of their essential role in, amongst others, permanent magnets for many high-tech and green applications such as electrical vehicles and wind turbines. Furthermore, Europe is highly dependent on the import from China for rare-earth compounds since almost all production is located there. Another critical metal considered in this PhD thesis is cobalt. Primarily because of its use in rechargeable batteries, also cobalt is essential to our transition to a sustainable society. Recovery of metals from solid waste materials generally requires the metals first to be extracted from the solid matrix by leaching. The obtained leachate contains besides the targeted metal ion, also several co-extracted metal ions. Solvent extraction is the most applied technique for the purification of metal ions from aqueous solution. It allows the efficient processing of large volumes of feed solution in a continuous mode.Recently, a new class of solvents found its way to the general public, namely ionic liquids. These liquids, containing only ions, have interesting properties including a negligible vapor pressure, a broad liquidus range and a broad electrochemical window. It is possible to design hydrophobic ionic liquids that are either able to solvate metal ions or dissolve metal-coordinating compounds. This resulted in the beginning of the 21st century in the application of ionic liquids in solvent extraction, and the research field has been growing ever since. Ionic liquids are often highlighted as green alternative solvents because of their negligible vapor pressure. On the other hand, safety is much more relevant. The ionic character and low flammability of ionic liquids makes them safer in use than traditional solvents. An important issue related to ionic liquid solvent extraction is the loss of ionic liquid constituents to the aqueous phase by ion exchange. Although this is not observed in every system, it should be checked for and prevented as much as possible.In this PhD thesis, a combination of fundamental research and a more applied approach is used to investigate the application of ionic liquid solvent extraction for the separation and recovery of the critical metals cobalt, scandium, yttrium and the lanthanides from industrial waste streams. The ionic liquid betainium bis(trifluoromethylsulfonyl)imide, [Hbet][Tf2N], was studied for the purification of scandium from bauxite residue leachates. To start, the extraction behavior of the various metal ions present in bauxite residue has been determined using synthetic solutions. Next, the system was applied to the waste material itself. Scandium was brought into solution by sulfation-roasting-leaching. Subsequently, Fe(III) was reduced to Fe(II) and Sc(III) was selectively extracted. After scrubbing and stripping with mineral acids, scandium was precipitated as a solid compound with oxalic acid and NaOH. Furthermore, the ionic liquid [Chol][Tf2N] was tested as a diluent for the extractant choline hexafluoroacetylacetonate, [Chol][hfac], and applied to the extraction of the lanthanides. Neodymium was chosen in particular, as a model ion, since all the lanthanides show similar chemical behavior. The extraction mechanism was investigated using solvent extraction techniques and crystal structure determination. It was concluded that the species [Chol][Nd(hfac)4] was formed in the organic phase. Finally, the separation of Co(II) and Ni(II) was investigated with two extraction systems, namely (1) a proof-of-principle of the use of ionic liquid-based aqueous biphasic systems for the separation of metal ions and (2) a study of the extraction of Co(II) from sulfate solution with the basic extractants trihexyl(tetradecyl)phosphonium chloride (Cyphos IL 101) and its thiocyanate salt.Finally, it was concluded that ionic liquids show potential for the recovery of critical metals from waste streams by solvent extraction. Advantages of the investigated systems included their selectivity towards the targeted metals and the fact that no organic solvents were used, hence the process was safer. Significant drawbacks were the high viscosity and high solubility in water of some of the investigated ionic liquids."