Setting up long-term strategies for efficient recovery of secondary resources and material circularity requires quantitative estimates of the total material amount available for recycling and annual scrap generation at end-of-life. This pre-condition is seldom available in statistics and builds upon the characterisation of anthropogenic material cycles. To this aim, material flow analysis (MFA) was applied to investigate physical flows and stocks along the whole metal lifecycle in the EU-28. For each target metal, the analysis was extended to the most recent years possible. The conservation of mass performed for each year of investigation provided an estimate of the cumulative metal in-use stock.
Life cycle assessment (LCA) was then employed to address the environmental sustainability dimension associated with resource recycling. Combining the elemental information from the MFA models with LCA inventories, the potential for energy savings and GHG emissions reduction were estimated both from current recycling and from a region-wide implementation of best available techniques. Uncertainty analysis was carried out to validate the robustness of the model created.
The project enabled to identify the application segments embedding the largest amount of secondary resources, which were found to be greater than the known domestic natural deposits in some cases. In addition, it was estimated that the annual flow of post-consumer scrap of the four metals could cover a substantial fraction of the metals demand by domestic manufacturers. Consequently, a virtual basis for closing the metal cycles seems to exist in the EU-28. While securing sustainable access to vital raw materials, pursuing efficient recycling would clearly benefit the environment, with substantial potentials for energy savings and GHG emissions reduction.
However, the end-of-life recycling performance is currently inexistent for indium, neodymium, and europium, and far from perfect conditions for copper. Establishing and maintaining a competitive recycling chain would require to tackle effectively the existing challenges to recycling including inefficiencies from product design to waste management. Ultimately, economic issues are often the main limitation to setting recycling strategies for these metals so that the development of feasible business models in collaboration with recyclers is needful.
Lastly, historic demand for the four metals was evidently related to economic wealth and population. As both drivers are expected to increase in the coming years, securing sustainable supply of the target metals through recycling might be not enough to reduce the pressure on the environment. In particular, a scenario analysis carried out for copper estimated that climate forcing could be significantly impacted by the anticipated energy requirement to meet the explored demand.
The planned strategy for the dissemination of the results was aimed at reaching a wide impact both in the scientific community and non-scientific audience. To this aim, open access is ensured to all the peer-reviewed scientific publications, while attending main conferences in the field enabled to present the results to the research community. Communication and outreach activities through training seminars and educational campaigns were devoted to a direct engagement with young students and the civil society. In addition, active participation to national and international workshops maximised the visibility of the project and provided the opportunity to communicate with policymakers, associations of producers, and industry experts.
