Periodic Reporting for period 1 - EXTREME (sElective eXtraction of plaTinum gRoup mEtals froM spent autocatalysts using deep Eutectic solvents)
Période du rapport: 2023-12-01 au 2025-11-30
Platinum Group Metals (PGMs) exhibit numerous desired properties such as corrosion resistance, high melting points, temperature stability, catalytic properties etc., making them highly valuable to the chemical and advanced materials industries. They are the most essential elements for the manufacturing of Automotive Catalytic Converters (ACCs) with more than 40% of the total EU PGMs demand consumed for ACCs production, corresponding to ca. 20% of the global demand. Europe is the highest consumer of platinum (Pt), and important consumer of palladium (Pd) and rhodium (Rh) for ACCs, which contain PGMs at ca 600 times greater amount than PGM ores. Higher PGM amounts are needed in ACCs of hybrid cars because of their emissions classification and the frequent starts their engines need to make. Given that PGMs production from mining is virtually non-existent in the EU and the dependence on their imports mostly from politically sensitive regions (South Africa, Russia, Canada), their efficient and cost-effective recycling and reuse in different applications such as catalysis, jewelry, medicine, electronics, etc., is of big financial, environmental, societal and political importance. Hence, PGMs are constantly in the EU’ s critical raw materials list. EXTREME establishes the collaboration of Y.S. Cypriot Catalysts Ltd (SME) with Stylianos Spathariotis (Experienced Researcher) to develop a breakthrough ACCs valorisation process to produce high purity PGMs streams for end-use applications and ease the EU PGMs dependence. Therefore, the research objectives of the project are:
ROI. To determine the optimum leaching system for high leaching efficiency of PGMs from spent autocatalysts, and research the chemical reactions and mechanisms during the process.
RO2. To research the interactions of the PGMs with other compounds in the DESs and the corresponding reactivities of the species formed, as well as the chemical reactions and mechanisms during electrowinning and cementation to achieve the selective recovery of PGMs streams at high purity.
RO3. To develop a TRL4 single pot process for the simultaneous leaching and recovery of PGMs from spent autocatalysts, achieving maximum space-time-yield and metal selectivity, while evaluate the overall sustainability of the process.
EXTREME will create significant scientific, economic and societal impacts to the EU ecosystems as below:
Scientific: The designing of new DESs and provision of significant insight into the chemistry and mechanism of PGMs leaching and recovery using these solvents. Furthermore, sophisticated techniques will be introduced in the project and be used to generate important scientific knowledge on the topic.
Economic: Cost-efficient and eco-conscious process for the extraction of expensive materials from end-of-life products. The process is expected to achieve high processing efficiency and reduced costs compared to SoA, arising from the one-pot processing, low-cost DES, and novel processing techniques.
Societal: Reduction of urban waste (ca 6 mio cars and their ACCs are scrapped in Europe per year), and elimination of harmful reagents, with significant environmental benefits for humans and fauna/flora that face risks due to improper disposal of heavy reagents. The project will trigger the securement of EU PGMs supply chain, contributing in independence from third country imports and reinforce environmental sustainability.
ROI. To determine the optimum leaching system for high leaching efficiency of PGMs from spent autocatalysts, and research the chemical reactions and mechanisms during the process.
RO2. To research the interactions of the PGMs with other compounds in the DESs and the corresponding reactivities of the species formed, as well as the chemical reactions and mechanisms during electrowinning and cementation to achieve the selective recovery of PGMs streams at high purity.
RO3. To develop a TRL4 single pot process for the simultaneous leaching and recovery of PGMs from spent autocatalysts, achieving maximum space-time-yield and metal selectivity, while evaluate the overall sustainability of the process.
EXTREME will create significant scientific, economic and societal impacts to the EU ecosystems as below:
Scientific: The designing of new DESs and provision of significant insight into the chemistry and mechanism of PGMs leaching and recovery using these solvents. Furthermore, sophisticated techniques will be introduced in the project and be used to generate important scientific knowledge on the topic.
Economic: Cost-efficient and eco-conscious process for the extraction of expensive materials from end-of-life products. The process is expected to achieve high processing efficiency and reduced costs compared to SoA, arising from the one-pot processing, low-cost DES, and novel processing techniques.
Societal: Reduction of urban waste (ca 6 mio cars and their ACCs are scrapped in Europe per year), and elimination of harmful reagents, with significant environmental benefits for humans and fauna/flora that face risks due to improper disposal of heavy reagents. The project will trigger the securement of EU PGMs supply chain, contributing in independence from third country imports and reinforce environmental sustainability.
The project generated a strong scientific foundation for a greener, integrated, and selective PGM recovery process, providing essential mechanistic understanding, optimized operational parameters, and a prototype of a combined leaching–electrochemical system for spent catalyst valorisation. Specifically, the project investigated the development of a sustainable, DES-based process for the selective recovery of platinum group metals (PGMs) from spent automotive catalytic converters (ACCs). The work began with the systematic synthesis and characterization of a wide range of Deep Eutectic Solvents (DESs), focusing on chloride-based mixtures capable of promoting oxidative leaching of Pt, Pd, and Rh. Detailed studies on viscosity, conductivity, complexation behavior, and stability enabled the identification of CaCl2:lactic acid (1:2) as the most promising DES for PGM dissolution.
Leaching experiments were carried out using real spent ACC samples, where the influence of temperature, solid-to-liquid ratio, oxidant addition, and reaction time was thoroughly evaluated. Under optimized conditions, the process achieved high dissolution efficiencies, particularly for Pd, and significant progress was made in enhancing Pt and Rh solubilisation. Parallel mechanistic studies provided valuable insight into the nature of chlorometalate complexes formed during leaching, supporting the rational design of downstream recovery steps.
The project then advanced to the selective recovery of PGMs through cementation and electrowinning. Experiments demonstrated that controlled redox manipulation within the DES environment enables preferential deposition of different PGMs. Potentiostatic electrodeposition trials successfully produced metallic deposits of Pd, Rh, and Pt, while characterization confirmed increasing metal purity and improved selectivity. These results validated the feasibility of electrochemical routes for metal separation directly from DES media.
Building on these findings, a TRL4 single-pot system integrating both leaching and electrodeposition was designed, constructed, and tested. This setup allowed continuous dissolution of PGMs from the solid material while selectively depositing them on electrodes in real time. Early demonstrations confirmed the operability and technical potential of the concept, with efficient Pd recovery and promising trends for Pt and Rh. Process sustainability was evaluated through preliminary energy, reagent, and waste assessments, reinforcing the environmental benefits of DES-based hydrometallurgy.
Leaching experiments were carried out using real spent ACC samples, where the influence of temperature, solid-to-liquid ratio, oxidant addition, and reaction time was thoroughly evaluated. Under optimized conditions, the process achieved high dissolution efficiencies, particularly for Pd, and significant progress was made in enhancing Pt and Rh solubilisation. Parallel mechanistic studies provided valuable insight into the nature of chlorometalate complexes formed during leaching, supporting the rational design of downstream recovery steps.
The project then advanced to the selective recovery of PGMs through cementation and electrowinning. Experiments demonstrated that controlled redox manipulation within the DES environment enables preferential deposition of different PGMs. Potentiostatic electrodeposition trials successfully produced metallic deposits of Pd, Rh, and Pt, while characterization confirmed increasing metal purity and improved selectivity. These results validated the feasibility of electrochemical routes for metal separation directly from DES media.
Building on these findings, a TRL4 single-pot system integrating both leaching and electrodeposition was designed, constructed, and tested. This setup allowed continuous dissolution of PGMs from the solid material while selectively depositing them on electrodes in real time. Early demonstrations confirmed the operability and technical potential of the concept, with efficient Pd recovery and promising trends for Pt and Rh. Process sustainability was evaluated through preliminary energy, reagent, and waste assessments, reinforcing the environmental benefits of DES-based hydrometallurgy.
The results obtained throughout the project, lay a solid foundation for future development, with clear opportunities for technological, economic, and environmental impact once the process is advanced toward industrial readiness.The project has generated a series of important scientific and technical results that collectively advance the development of a sustainable, DES-based process for recovering PGMs from spent automotive catalytic converters. Key achievements include the identification of an efficient chloride-based DES system capable of dissolving Pt, Pd, and Rh; the detailed understanding of metal–DES interactions and complex formation; and the successful demonstration of selective PGM recovery via cementation and electrowinning. Furthermore, the design and operation of a TRL4 single-pot leaching–electrodeposition prototype represents a significant step toward an integrated, low-waste, and environmentally friendly metallurgical solution.
These results have strong potential to create impact in the European circular economy sector. A greener, non-aqua-regia technology for PGM recovery contributes directly to supply-chain resilience and reduces reliance on imported raw materials. The integrated process also offers possibilities for lowering the carbon footprint of critical raw material extraction, supporting EU strategic objectives on sustainability and resource autonomy. To ensure further uptake and eventual industrial success, several needs and enabling conditions have been identified. Continued research is required to further enhance leaching efficiency for Pt and Rh, optimise electrodeposition selectivity, and increase the stability and recyclability of the DES system. A demonstration stage at higher TRLs, including continuous operation and pilot-scale validation, will be essential to confirm process robustness and economic viability. Access to funding instruments such as Horizon Europe, EIC, or national innovation schemes will support this scale-up pathway. On the route to commercialisation, IPR protection for promising process innovations could strengthen market positioning while attracting industrial partners. Close collaboration with catalyst recyclers, PGM refiners, and automotive industry stakeholders will be crucial for market penetration and supply-chain integration. Finally, a supportive regulatory environment and alignment with emerging EU standards for sustainable recycling processes would further enable deployment and promote investor confidence.
These results have strong potential to create impact in the European circular economy sector. A greener, non-aqua-regia technology for PGM recovery contributes directly to supply-chain resilience and reduces reliance on imported raw materials. The integrated process also offers possibilities for lowering the carbon footprint of critical raw material extraction, supporting EU strategic objectives on sustainability and resource autonomy. To ensure further uptake and eventual industrial success, several needs and enabling conditions have been identified. Continued research is required to further enhance leaching efficiency for Pt and Rh, optimise electrodeposition selectivity, and increase the stability and recyclability of the DES system. A demonstration stage at higher TRLs, including continuous operation and pilot-scale validation, will be essential to confirm process robustness and economic viability. Access to funding instruments such as Horizon Europe, EIC, or national innovation schemes will support this scale-up pathway. On the route to commercialisation, IPR protection for promising process innovations could strengthen market positioning while attracting industrial partners. Close collaboration with catalyst recyclers, PGM refiners, and automotive industry stakeholders will be crucial for market penetration and supply-chain integration. Finally, a supportive regulatory environment and alignment with emerging EU standards for sustainable recycling processes would further enable deployment and promote investor confidence.