Title Promoter Affiliations Abstract "Non-aqueous solvent extraction of metal ions" "Koen Binnemans" "Process Engineering for Sustainable Systems (ProcESS), Sustainable Chemistry for Metals and Molecules" "The transition towards a climate-neutral, eco-friendly economy critically depends on the availability of a wide variety of high-purity metals (e.g. cobalt). Solvent extraction (liquid-liquid extraction) is an important unit process used by the metallurgical industry for the recovery, separation and purification of metal salts. Solvent extraction is based on distribution of metal ions between two immiscible liquid phases, often an aqueous and an organic phase. Tis project investigates non-aqueous solvent extraction, which involves two immiscible organic phases. This allows to obtain other selectivities than in aqueous solutions. This project targets the intensification of solvent extraction technology for small-volume, but high-value streams containing critical metals. To that end, research is performed on the chemical development and optimisation of solvent extraction systems in milliflow devices using non-aqueous solvent extraction with ionic liquids. The work will be performed on three case-studies: the preparation of battery-grade cobalt, the separation of platinum/ palladium/rhodium and the purification of germanium. The project results enable to increase the efficiency of separation processes in the metallurgical and chemical industry." "Non-aqueous solvent extraction of metal ions in milliflow reactors (NERO)" "Koen Binnemans" "Process Engineering for Sustainable Systems (ProcESS), Sustainable Chemistry for Metals and Molecules" "Solvent extraction (liquid-liquid extraction) is an important unit process used by the metallurgical industry for the recovery, separation and purification of metal salts. Solvent extraction is based on the distribution of metal ions between two immiscible liquid phases, often an aqueous and an organic phase. The NERO project investigates non-aqueous solvent extraction, which is based on the distribution of metal ions between two immiscible organic phases. This allows to get other selectivities than in aqueous solutions. This project deals with the intensification of solvent extraction technology for small-volume, but high-value streams containing critical metals. To that end, research is performed on 1) the chemical development and optimisation of solvent extraction systems in milliflow devices using non-aqueous solvent extraction with ionic liquids, 2) the improvement of contacting and separation efficiency by the application of ultrasound in these milliflow devices, and 3) the scale up and application of the (both chemically and technologically) intensified system. The work will be performed on three case-studies: the preparation of battery-grade cobalt, the separation of platinum/ palladium/rhodium and the purification of germanium. The project results enable to increase the efficiency of separation processes in the materials and chemical industry, and contribute to the sustainable chemical processing in society." "Mechanism of solvent extraction of metal ions by basic extractants" "Koen Binnemans" "Sustainable Chemistry for Metals and Molecules" "To date, solvent extraction is the best available technology for metal separation on industrial scale. Solvent extraction involves two immiscible liquid phases: an aqueous and an organic phase containing organic molecules (extractant). A metal distributes between the aqueous and the organic phase based on its affinity for the organic and aqueous phase. There exist three types of extractants: acidic, neutral and basic ones. The metal extraction mechanism of basic extractants is typically described as an anion exchange process, in which a negatively charged metal species transfers from the aqueous to the organic phase and an anion transfers from the organic phase back to the aqueous phase. In this project, a better fitting metal extraction mechanism is proposed for basic extractants in which a neutral species transfers to the organic phase and there reacts with the basic extractant. The aim of the project is to find scientific evidence supporting this hypothesis. The chemical equilibria of the metal species in both the aqueous and organic phase are investigated and the metal extraction mechanism is described mathematically. These new insights in the extraction of metals make it possible to better predict metal extraction and metal separations by basic extractants." "Mechanism of solvent extraction of transition metal ions by basic extractants" "Koen Binnemans" "Sustainable Chemistry for Metals and Molecules" "To date, solvent extraction is the best available technology for metal separation on industrial scale. Solvent extraction involves two immiscible liquid phases: an aqueous and an organic phase containing organic molecules (extractant). A metal distributes between the aqueous and the organic phase based on its affinity for the organic and aqueous phase. There exist three types of extractants: acidic, neutral and basic ones. The metal extraction mechanism of basic extractants is typically described as an anion exchange process, in which a negatively charged metal species transfers from the aqueous to the organic phase and an anion transfers from the organic phase back to the aqueous phase. In this project, a better fitting metal extraction mechanism is proposed for basic extractants in which a neutral species transfers to the organic phase and there reacts with the basic extractant. The aim of the project is to find scientific evidence supporting this hypothesis. The chemical equilibria of the metal species in both the aqueous and organic phase are investigated and the metal extraction mechanism is described mathematically. These new insights in the extraction of metals make it possible to better predict metal extraction and metal separations by basic extractants." "Intensified metal purification by solvent extraction with ionic liquids in milliflow reactors" "Koen Binnemans" "Sustainable Chemistry for Metals and Molecules, Process Engineering for Sustainable Systems (ProcESS)" "High-purity metals are essential for many modern applications such as electric vehicles, solar cells, wind turbines, and smartphones. Metals are, however, not readily available in the necessary purity and metal production processes typically require a variety of different operations. Among such operations is solvent extraction, a technique commonly used for the purification and separation of metallic species based on differences in their distribution over two immiscible liquid phases.Ensuing the continual search for more sustainable solvent extraction processes, the use of ionic liquids has become increasingly popular. Ionic liquids are solvents that consist entirely out of ions and are characterised by a negligible volatility, low flammability, and intrinsic electrical conductivity. Such properties make them inherently safer and more environmentally friendly than the conventional, molecular solvents commonly used in the industry. Moreover, because of their modular and ionic character, ionic liquids are highly tunable and can be tailor-made for a particular application. An increased process efficiency and/or selectivity can thus often be achieved. Despite their advantages, the practical applications of ionic liquids are, however, far from widespread. The relatively high price of ionic liquids makes substitution of cheap, molecular chemicals hard to justify from an economic point of view. In addition, ionic liquids generally display a high viscosity which can hinder mechanical manipulations and slow mass and heat transfer rates.In recent years, the use of milli- or microfluidic reactors has been proposed as a possible answer to these drawbacks. Millifluidic technology involves the manipulation of fluids in channels with small dimensions, typically less than 5 mm. The use of such small reactor dimensions is generally accompanied by improved mass and heat transfer rates, increased specific interfacial areas, a reduced energy consumption, and an improved process control. In combination with the small reactor volume, an intensified solvent use can thus be expected and the use of ionic liquids may very well become more economically viable. However, thus far only few research efforts have covered metal separations using ionic liquids in milli- or microfluidic reactors.Over the course of this PhD, the combination of ionic liquids and millifluidic reactors was explored for the solvent extraction separation and purification of metals. A first part of the work covers the development of two new solvent extraction processes using undiluted ionic liquids. The investigated case studies, namely precious metal separations and germanium purification are industrially relevant. Precious metals find use in car exhaust catalysts and electronics, while germanium is used in fibre-optics and photovoltaic cells. The first solvent extraction process involves the separation of gold and palladium from copper and iron rich solutions using an undiluted quaternary ammonium bromide ionic liquid and may be applicable to the recycling of waste electrical and electronic equipment. The second separation procedure concerns the recovery of germanium from a synthetic zinc refinery residue leachate containing zinc, iron, copper, and arsenic as contaminants using an undiluted quaternary ammonium hydrogensulphate ionic liquid.The second part of the work deals with the application and evaluation of the developed separation procedures in millifluidic reactors. Overall, the undiluted ionic liquids were found to be compatible with millifluidics and improved mass-transfer rates, manifested by rapid, second-scale metal extractions, were achieved. The improved process control also proved useful as enhanced extraction selectivities were achieved by exploitation of differences in extraction rate and precise contact time modulation. An evaluation and comparison of the hydrodynamic and mass transfer performance of diluted and undiluted ionic liquids eventually paved the way towards the development of an integrated setup combining various metallurgical operations into a single millifluidic device.Following the use of ionic liquids incorporating various anions, the final part of the work involved a more in depth study of the ionic liquid metathesis or anion-exchange process. To monitor the progression of the anion exchange process, wavelength dispersive X-ray fluorescence (WDXRF) was explored. The metathesis of ionic liquids was subsequently investigated in a counter-current lab-scale mixer-settler. Significant improvements in product conversion, reagent consumption, and waste generation were achieved." "Intensified SOlvent extraction for critical MEtal Recovery (ISOMER)" "Tom Van Gerven" "Process Engineering for Sustainable Systems (ProcESS), Sustainable Chemistry for Metals and Molecules, Sustainable Materials Processing and Recycling (SeMPeR)" "This project deals with the intensification of solvent (liquid-liquid) extraction technology for small-volume, but high-value streams containing critical metals. To that end, research is performed on 1) the chemical development and optimisation of solvent extraction systems in milliflow devices using ionic liquids, 2) the improvement of contacting and separation efficiency by the application of ultrasound in these milliflow devices, and 3) the scale up and application of the (both chemically and technologically) intensified system, including the comparison to the conventional mixer-settler approach. The work will be performed on three case-studies. The project results enable to increase the efficiency of separation processes in the materials and chemical industry, and contribute to the sustainable chemical processing in society." "SMART: sustainable metal extraction from tailings" "Department of Green Chemistry and Technology, Department of Applied analytical and physical chemistry" "The aim of this project is to develop a generic toolbox for sustainable metal extraction from both historical and newly produced tailings, by using combinations of advanced hydrometallurgical, solvometallurgical and biometallurgical methods. After the metal extraction, a clean mineral residue remains. The technologies envisaged have a dual form of selectivity: a high solubility of the targeted metals (including precious metals: In, Ge, Ga, Sb, W, PGMs, REEs, Co, V, Mo, W, environmentally harmful metals: Ash, Cd, Tl, Hg, U) and a low solubility of the mineral (tailings) matrix. The SMART toolbox consists of a multitude of both existing and new unitary processes, which can be combined in function of the specific tailings family." "Combined Heat, Power and Metal extraction from ultra-deep ore bodies" "Jan Fransaer" "Surface and Interface Engineered Materials (SIEM)" "CHPM2030 aims to develop a novel and potentially disruptive technology solution that can help satisfy the European needs for energy and strategic metals in a single interlinked process. Working at the frontiers of geothermal resources development, minerals extraction and electro-metallurgy the project aims at converting ultra-deep metallic mineral formations into an “orebody-EGS” that will serve as a basis for the development of a new type of facility for “Combined Heat, Power and Metal extraction” (CHPM). In the technology envisioned the metal-bearing geological formation will be manipulated in a way that the co-production of energy and metals will be possible, and may be optimised according to the market demands at any given moment in the future. The workplan has been set up in a way to provide proof-of-concept for the following hypotheses:The composition and structure of orebodies have certain advantages that could be used to our advantage when developing an EGS;Metals can be leached from the orebodies in high concentrations over a prolonged period of time and may substantially influence the economics of EGS;The continuous leaching of metals will increase system’s performance over time in a controlled way and without having to use high-pressure reservoir stimulation, minimizing potential detrimental impacts of both heat and metal extraction.As a final outcome the project will deliver blueprints and detailed specifications of a new type of future facility that is designed and operated from the very beginning as a combined heat, power and metal extraction system.The horizontal aim is to provide new impetus to geothermal development in Europe by investigating previously unexplored pathways at low-TRL. This will be achieved by developing a Roadmap in support of the pilot implementation of such system before 2025, and full-scale commercial implementation before 2030" "Sustainable metal extraction from tailing" "Koen Binnemans" "Sustainable Chemistry for Metals and Molecules, VITO, Universiteit Gent" "The purpose of this project is to develop a generic toolbox for sustainable metal extraction from both historical and newly produced tailings, using combinations of advanced hydrometallurgical solvometallurgical and biometallurgical methods. After the metal extraction, a clean mineral residue remains.The technologies provide a dual form of selectivity: high solvability of the vitreous metals and low solvability of the mineral (tailings) matrix. The SMART toolbox consists of a multitude of both existing and new unit processes, which can be combined in function of the specific tailings family." "Base-stable ionic liquids for extraction of metal ions from alkaline aqueous solutions" "Koen Binnemans" "Sustainable Chemistry for Metals and Molecules" "Ionic liquids are solvents that consist entirely of ions. They have unique properties such as a very low vapor pressure, an intrinsic electric conductivity and a good thermal stability. They can act as solvents for many types of organic and inorganic compounds. Ionic liquids have applications ranging from solvents for catalytic organic reactions, over solvents for liquid-liquid extraction to electrolytes for batteries. Although ionic liquids are very stable against strong acids, most ionic liquids have a poor stability towards strong bases. This project is about the design of a new class of base-stable ionic liquids, derived from highly substituted 1,2,3-triazoles. The stability of these new triazolium ionic liquids against different types of strong bases is tested. Water-immiscible triazolium ionic liquids are used as organic phase for solvent extraction of metal ions from alkaline aqueous feed solutions. "