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CIRMET, representing “Circular hydrometallurgy for energy-transition metals”, is the ERC Advanced Grant Project of Prof. Koen Binnemans and his team at KU Leuven.
CIRMET received funding from the European Research Council (ERC) under the European Union’s Horizon Europe Research and Innovation Programme: Grant Agreement 101093943.
The project runs from 01/05/2023 to 30/04/2028.
We face a paradox: the production and refining of the “energy-transition metals” that are necessary for a climate-neutral society have a very negative environmental impact. Traditional, linear hydrometallurgical flowsheets used for extracting and refining the energy-transition metals cobalt (Co) and nickel (Ni) produce multiple solid and liquid waste streams and consume large amounts of high-carbon-footprint chemicals.
CIRMET will lead to a new approach to hydrometallurgy, called “circular hydrometallurgy”, with a focus on the design of energy-efficient flowsheets or unit processes that consume a minimum amount of reagents and produce virtually no waste. CIRMET has the ambitious goal to replace the incumbent l-linear hydrometallurgical flowsheets for extraction and refining of the “energy-transition” metals cobalt and nickel into a next-generation, circular flowsheet, which:
● consumes no chemicals other than (green) hydrogen, water and carbon dioxide (taking advantage of the unique chemical properties of carbon dioxide);
● uses the acid for the leaching process as a “catalyst” that is continually regenerated rather than consumed;
● reduces the net consumption of acids and bases to virtually zero through ingenious manipulations of chemical equilibria via solvent extraction;
● comprises a virtually zero discharge of solid and liquid waste streams.
As such, CIRMET can drastically reduce the environmental footprint of hydrometallurgical processes. To enable such circular flowsheets, a new theoretical chemical thermodynamic framework for multiphase electrolyte equilibria involving two immiscible liquids and innovative unit operations for sustainable metal and sulphur recovery are developed. Hydrometallurgical processes are approached from a molecular level. Liquid-liquid equilibria are modelled by Gibbs-energy-minimisation (GEM) methods, rather than by solving law-of-mass action (LMA) equations.
The proof of concept of circular flowsheets is demonstrated for metal recovery from real, complex (rather than synthetic), impurity-bearing input streams: nickel laterites, cobalt-nickel sulphide ores, mixed hydroxide precipitate (MHP), and mixed sulphide precipitate (MSP). Only by combining these three mutually supporting spheres of innovation – (1) the “thermodynamic framework”, (2) the “unit process level” and (3) the “general flowsheet” sphere – can CIRMET be successful.
The CIRMET project begins with the research question “How can we transform linear hydrometallurgical flowsheets for Co/Ni recovery and refining to circular ones with the constraint that no chemicals other than H2, H2O and CO2 are used?”
To answer this, CIRMET has two meta-objectives:
1) to develop a next-generation, predictive thermodynamic framework that enables process engineers to model the liquid-liquid equilibria that are crucial for circular Co/Ni flowsheets
2) to demonstrate that circular Co/Ni hydrometallurgical flowsheets, consuming no chemicals other than H2, H2O and CO2, are possible by the ingenious application of SX systems.
● Our world is moving towards a climate-neutral economy. The global energy system is becoming less dependent on fossil fuels, and increasingly more so on metals. The demands for cobalt and nickel necessary for the production of batteries will be, respectively, 21 and 19 times higher in 2040 than they are now.
● Right now, the production and refining of these metals is not environmentally friendly. This is due to the fact that hydrometallurgical processes used in production are not energy-efficient, even when performed at ambient conditions. Moreover, they generate a lot of liquid and solid waste.
● CIRMET aims to design a low-energy-input, circular hydrometallurgical flowsheet. This novel flowsheet consumes no chemicals other than hydrogen gas, water, and carbon dioxide.
● To reach this goal, CIRMET will employ a technology called solvent extraction in an innovative way, so that acids are regenerated and no toxic or difficult-to-treat waste is produced.
● In order to create a circular hydrometallurgical flowsheet, CIRMET examines the metallurgical processes from a molecular level. Accurate thermodynamic models will be created to model the solvent extraction process.
● CIRMET will support the shift from the present linear, waste-generating hydrometallurgy to low-energy-input circular hydrometallurgy, which is required for the green transition
Circular hydrometallurgy relates to the design of energy-efficient and resource-efficient flowsheets or unit processes that consume a minimum of reagents and produce as minimum waste as possible. While the idea of circularity in hydrometallurgy is not new, only partial circularity can often be found in existing hydrometallurgical processes (e.g. extractant is regenerated during the stripping of the metal from the loaded organic phase).
Unfortunately, the wide availability of cheap bulk chemicals such as sulphuric acid or quicklime, and the relatively low costs associated with the landfilling of industrial process residues and wastes have slowed the development of genuinely circular metallurgical flowsheets. However, today’s mining and metallurgical engineers have the moral duty to minimize the impact of primary mining and of the downstream processing of the extracted metals on the environment. There is no alternative to transforming linear flowsheets into circular flowsheets.
Prof. Koen Binnemans is an inorganic chemist and full professor at KU Leuven (Belgium). He is head of the Laboratory of Metallurgical Chemistry (SOLVOMET Group). His main research lines are: (1) critical metals, with a focus on energy-transition metals (rare earths, lithium, cobalt, nickel, manganese); (2) solvent extraction, (3) hydrometallurgy and (4) solvometallurgy. Koen Binnemans has created the concept of Circular Hydrometallurgy and its 12 Principles. Circular hydrometallurgy refers to the designing of energy-efficient and resource-efficient flowsheets or unit processes that consume the minimum quantities of reagents and result in minimum waste. The application of a circular approach involves new ways of thinking about how hydrometallurgy is applied for both primary and secondary resources.Koen Binnemans has published close to 600 papers in international journals. His work has been cited 36,900 times (h-index = 90) according to Web of Science, and 51,000 times (h-index = 108) according to Google Scholar. In 2016, he was awarded his first ERC Advanced Grant (SOLCRIMET) on the use of solvometallurgy for the recovery of critical metals. He is a key member of the KU Leuven Institute for Sustainable Metals and Minerals (SIM² KU Leuven).
In 2017, Koen Binnemans co-founded together with Peter Tom Jones the Research and Innovation Centre “SOLVOMET”. SOLVOMET’s mission is to support its industry partners in the conceptual and practical development of more sustainable (circular, low-energy input) hydrometallurgical (and solvometallurgical) processes, which are subsequently tested using state-of-the-art lab-scale and mini-pilot-scale experimental facilities.
Koen Binnemans is a key member of the KU Leuven Institute for Sustainable Metals and Minerals (SIM²). SIM² is one of the official KU Leuven Institutes with a mission “to develop, organise & implement problem-driven, science-deep research & future-oriented education, contributing to the environmentally friendly production & recycling of metals, minerals & engineered materials, supporting a climate-friendly, circular-economy”.
Due to the green transition, the global energy system is shifting from a reliance on fossil fuels to an increasing dependence on metals. This shift is driven by the fact that solar photovoltaic plants, wind farms, and electric vehicles generally require more raw materials for their construction than their fossil fuel-based counterparts. For instance, a typical electric car demands six times more mineral inputs than a conventional car, and an onshore wind plant requires nine times more mineral resources than a gas-fired plant (IEA, 2021).
In its 2021 report, “The Role of Critical Minerals in Clean Energy Transitions,” the International Energy Agency estimated that by 2040, the demand for battery-grade cobalt and nickel will be 21 and 19 times higher, respectively, than current levels. Therefore, it is crucial to ensure that the production and refining processes for these minerals are environmentally sustainable. Presently, this is not the case. Hydrometallurgical processes, though performed at ambient conditions, are not energy-efficient. These processes often involve numerous steps of dissolution, precipitation, and redissolution, which consume significant amounts of acids and bases and generate large volumes of liquid and solid waste.
We are thus confronted with a paradox: the production and refining of the “energy-transition metals” essential for achieving a climate-neutral society have a considerable environmental impact. Additionally, switching from primary mining to the recycling of cobalt and nickel is not a comprehensive solution. Recycling end-of-life batteries involves similar hydrometallurgical processes with high carbon footprints and can meet, at most, only 10% of the demand for energy-transition metals (IEA, 2021).
The CIRMET project aims to revolutionize this field by replacing the traditional linear hydrometallurgical flowsheets used for extracting and refining cobalt and nickel with next-generation, low-energy-input, and circular flowsheets. These circular flowsheets use only environmentally friendly chemicals such as hydrogen gas, water, and carbon dioxide, consume minimal reagents, and produce virtually no waste. To achieve this, the project employs existing solvent exchange technologies innovatively while seeking a deeper understanding of hydrometallurgical processes at the molecular level. By coupling experimental work with predictive simulations at both the molecular and flowsheet levels, CIRMET aims to develop optimal solutions.
This novel approach, termed “circular hydrometallurgy,” focuses on designing energy-efficient flowsheets that minimize reagent use and waste production. Achieving a climate-neutral society by 2050 heavily depends on hydrometallurgy to extract critical raw materials like cobalt, nickel, and others. However, it is imperative to ensure that the processes used to refine these metals for clean-energy production do not counteract our environmental efforts. This is the mission of the CIRMET project.
