Recent years have witnessed rapid progress in technology and the economy [1], with the manufacturing of electrical and electronic products becoming one of the fastest-growing industries [2]. Waste generated from electrical and electronic equipment is a major type of complex waste as it encompasses a diverse array of materials, including metals, plastics, and chemicals, which are intrinsically intertwined, posing challenges in the processing and recycling of this waste stream. These materials frequently incorporate hazardous components, necessitating specialised disposal protocols [3]. The rate of Waste Electrical and Electronic Equipment (abbreviation: WEEE) generation is significant and continues to grow globally. According to recent estimates, over 50 Mt of WEEE are generated annually worldwide [4]. In the European Union alone, the generation of WEEE is estimated to be around 12 Mt/y [5]. The growing demand for electronic products requires significant resources, particularly various metals like gold, silver, copper, palladium, and tantalum that are used in electronic components [6]. Additionally, plastics, glass, and rare earth metals such as neodymium and lithium are essential for modern technologies [7]. From an economic perspective, it is projected that e-waste recycling could generate around 2×10⁹ EUR in revenue in Europe [8]. Furthermore, factors like increased economic development, urbanisation, Industry 4.0 advancements, and technological innovation contribute to the rapid turnover of products [9]. The rise of an information-focused society has led to high consumption rates of Electrical and Electronic Equipment [8], with the growth rate for WEEE typically being three times faster than that of municipal waste [10]. To address this issue, there is a growing shift towards adopting circular economy principles [11]. The circular economy focuses on designing products with their entire lifecycle in mind [12], aiming to minimise waste and maximise resource recovery [13]. By transitioning to a circular economy model, industries can reduce reliance on virgin resources [14], enhance material recovery processes, and ultimately contribute to a more sustainable future [15].

According to these, the European Union has implemented legislation to improve e-waste management, such as the Waste Shipment Regulation, which prohibits the export of hazardous e-waste to non-OECD countries [14]. Directives like the second WEEE Directive and the RoHS2 Directive have also contributed by regulating hazardous substances in electronic equipment and promoting e-waste collection and recycling [15]. Despite these improvements, there are still challenges in changing consumer behaviour and adopting circular economy practices. As part of the European Green Deal, a New Circular Economy Action Plan was introduced, focusing on promoting longer product lifetimes through a circular electronics initiative [16]. Given the depletion of raw materials, alternative extraction solutions from reclaimed landfills can provide critical raw materials. However, this requires sustainable waste management practices and secondary material market development [17]. The EU's Critical Raw Materials Act aims to extract rare earth elements from waste streams based on their economic importance and supply risk [18]. Overall, clear regulations are needed for responsible material extraction and recycling to utilise electronic waste effectively.

Urban mining is closely related to circular economy principles and plays a crucial role in efficient waste management and resource conservation [16]. Urban mining recovers valuable materials from urban settings, including buildings, infrastructure, and electronic waste, reducing the environmental impact of traditional mining and promoting sustainable use of rare metals and other materials [17]. The recovery of precious metals, such as gold, silver, and platinum, from discarded electronic devices presents a significant opportunity [18]. Copper is another frequently recovered metal sourced from electrical cables and wires [19]. Additionally, aluminium and iron play significant roles, as they are commonly found in construction materials and transportation equipment [20]. Leveraging urban mining techniques can diminish the need for conventional mining by enabling the recycling and reuse of existing materials [21].

This practice has become increasingly important due to a variety of factors. As cities expand, there is a heightened need for resources like metals, minerals, and rare earth elements. Another factor contributing to urban mining is the greater recognition of the environmental impact caused by traditional mining methods. Such activities have significant consequences, such as deforestation, water pollution, and habitat destruction. Urban mining presents a more sustainable option by utilising existing material stocks within cities rather than relying on new resource extraction [22]. However, a lack of awareness and understanding about this concept remains a major obstacle. Many individuals are still unaware of the potential value hidden in urban environments, such as recyclable or reusable materials. Additionally, the implementation challenges could be attributed to technological barriers. Jacobs (1961) suggested the extraction of rare metals and other raw materials in cities in her book “The Economy of Cities” [23]. Today, numerous researchers and organisational units consider urban mining a viable approach for recovering secondary raw materials from electronic waste [24]. The term urban mining also refers to the extraction of valuable materials from industrial and urban activities and associated services and information flows. Waste materials from human activities, or man-made ores, are also referred to as anthropogenic sources [25]. Moreover, it is important to note that urban mining is closely related to the concept of the circular economy, as both aim to promote sustainable resource use and waste reduction. Consequently, the combination of urban mining and circular economy principles facilitates the reduction of resource extraction and significantly promotes sustainable economic growth and conservation of natural resources [26]. One of the greatest potentials of urban mining lies in its application to landfills, which can be effective in recovering various end-of-life products from human consumption, such as industrial electrical and non-electrical equipment waste, construction and demolition waste, municipal solid waste, end-of-life vehicles, and electronic and electrical equipment waste [27].

The current literature commonly examines the advantages of urban mining and circular economy concepts, but it also highlights several specific gaps. Firstly, there is often a dearth of detailed quantitative analyses regarding the efficiency of material recovery across various technologies. Secondly, comprehensive comparisons of different urban mining techniques are frequently absent, leaving uncertainty around the most cost-effective methods. Additionally, limited research exists on how urban mining can be integrated into specific circular economy models, as well as insufficient exploration of technological and policy barriers. This paper seeks to fill the existing knowledge gap by providing detailed quantitative data on the recovery efficiencies and theoretical recoverable potentials of different materials along the four most recovered precious metals.

The reviewed articles collectively highlight the growing importance of urban mining and e-waste management in promoting sustainability and resource efficiency. While some studies focus on technological advancements and machine learning applications for optimising copper recovery from printed circuit boards, others explore broader frameworks such as community engagement and regulatory implications [28]. A common thread is the emphasis on circular economy principles [29], whether addressing the reuse of construction materials, as demonstrated in urban mining feasibility studies [30], or the complexities of value recovery from e-waste. Innovative methods [17], including hyperspectral imaging and the integration of 3D city modelling [31] further underscore the interdisciplinary nature of this research field. Despite progress, challenges remain in achieving scalability, the need for specialised expertise, and the development of harmonised policies, all of which are essential for widespread adoption and impactful implementation.

This paper addresses the pressing issue of e-waste in Hungary by evaluating urban mining as a sustainable resource recovery strategy. Specifically, this paper provides a comprehensive, data-driven analysis of the theoretically recoverable metal stocks from EEE waste streams based on national waste management data and average metal content values. The novelty of this research lies in its quantitative approach to estimating resource recovery potential at a national scale, a perspective that is underrepresented in current literature. By focusing on Hungary as a study area, this work contributes valuable insights into urban mining's role in supporting circular economy objectives and resource efficiency, offering a replicable framework for other regions facing similar waste management challenges.

This research hypothesises that the recovery rates of precious metals from e-waste are substantially influenced by the technologies and preprocessing methods employed and also exhibit measurable regional and temporal variations. The theoretical potential for recovering these metals can be estimated using a combination of time-series data, comparative analysis, and scenario modelling, highlighting the viability and scalability of urban mining practices. The study introduces a comprehensive methodology for assessing urban mining processes by integrating regional data on waste generation, treatment techniques, and material composition. The novel aspect lies in its systematic quantification of recoverable precious metals in WEEE through advanced statistical methods and scenario-based modelling. Furthermore, the exploration of regional variations and recovery coefficients provides new insights to optimise urban mining practices and evaluate the environmental advantages of such processes.

The aim of the current research is to assess the potential for precious metals recovery using theoretical potential information on urban mining processes. A significant volume of data from various sources on a broad spectrum of WEEE was analysed in the paper. This paper will analyse data by first compiling comprehensive information on the performance of diverse urban mining techniques employed for recovering precious metals. This entails calculating fundamental statistical measures, such as the mean and standard deviation, regarding the recovery rates, and conducting comparative analyses to identify the most effective methodologies. To evaluate the theoretical potential for recoverable resources, the investigation will estimate the total quantity of precious metals that could potentially be extracted from various waste sources by theoretical models and scenario analyses (Figure 1).

Figure 1.

A conceptual diagram depicting the workflow and techniques of the research methodology

The analysis of WEEE recycling rates and waste generation trends from 2010 to 2021 provides a comprehensive understanding of the complexities surrounding resource recovery and waste management in the EU and Hungary. The data reveals a multifaceted landscape: while some EU member states, such as Croatia, Finland, and Slovakia, have achieved noteworthy recycling rates, the overall trends across the EU-27 suggest a modest decline in recycling performance. Similarly, Hungary has experienced a gradual reduction in recycling rates over the same period. Concurrently, Hungary has witnessed a significant increase in total waste generation, particularly pronounced in regions like Pest and Central Transdanubia, underscoring an urgent need for robust resource recovery initiatives and effective waste management policies to address these pressing challenges.

Examining WEEE waste generation in Hungary over a broader period, from 2004 to 2022, reveals an extraordinary increase of 668%, with annual volumes rising from 4,247.64 t to 32,620.65 t. This dramatic growth underscores the critical need for more effective and scalable waste management and recycling strategies. Metals like copper demonstrate significant recovery potential, presenting opportunities for resource recovery efforts to focus on materials with high economic and environmental value. However, recovery rates for other valuable metals, such as gold, silver, and palladium, show considerable variability, emphasising the need for advancements in waste processing technologies and more sophisticated predictive models to ensure accurate recovery estimates and optimised recycling processes.

Furthermore, the data highlights stark regional disparities in waste generation, with Central Transdanubia and Budapest emerging as areas of particularly high production levels. These disparities suggest that region-specific challenges are a critical component of the broader waste management landscape and point to the necessity of implementing tailored strategies to address the unique characteristics and needs of different regions.

Urban mining has emerged as a promising and innovative solution, providing an alternative to traditional mining by enabling the recovery of valuable metals directly from urban waste streams [36]. This approach is firmly rooted in circular economy principles, offering the dual benefits of reducing reliance on virgin resources while supporting the transition to a sustainable, resource-efficient economy [15]. However, despite its potential, the variability observed in recovery rates underscores significant technical and logistical challenges [37]. These challenges include optimising pre-processing techniques, improving collection and sorting systems, and advancing recycling technologies to enhance efficiency and minimise material losses [38]. Addressing these issues is essential to fully realising the benefits of urban mining and integrating it as a cornerstone of sustainable waste management in the EU and Hungary.

This paper presents a comprehensive analysis of WEEE recycling rates, waste generation trends, and the potential for urban mining in Hungary and the EU. The findings offer valuable insights into the critical intersections of sustainability, resource recovery, and waste management. The analysis emphasises the urgent need to advance waste processing technologies to optimise recovery efficiencies for high-value metals such as copper, gold, silver, and palladium. These advancements could significantly enhance the economic viability of recycling operations while reducing environmental impacts. Furthermore, the observed regional disparities in waste generation across Hungary underline the importance of designing region-specific strategies that address unique waste management challenges and resource recovery opportunities.

The significant increase in waste quantities in Hungary, coupled with variability in the recoverable content of metals, underscores the potential benefits of transitioning to a circular economy model. By integrating urban mining into national and EU-level waste management strategies, Hungary and its European counterparts can reduce their reliance on finite primary resources, mitigate environmental degradation, and foster long-term sustainable growth. Urban mining, as a component of the circular economy, represents a transformative approach that aligns economic and environmental goals, emphasising the recovery of valuable materials from waste streams that would otherwise be discarded.

Advancing waste processing technologies should be a priority for future research, particularly in enhancing recovery rates and minimising losses of critical materials. Additionally, deepening the understanding of regional variations in waste generation is essential to effectively tailor strategies to local needs. Furthermore, developing sophisticated predictive models can further improve planning and decision-making, empowering stakeholders to anticipate and address emerging challenges in resource recovery and waste management.

Implementing a robust and forward-thinking policy framework is crucial for driving these efforts. Policies that incentivise recycling initiatives, urban mining, and sustainable waste management practices will be pivotal in overcoming existing barriers to the adoption of circular economy principles. This includes providing financial incentives for companies to adopt advanced recycling technologies, enacting regulations mandating higher recovery rates for specific materials, and launching public awareness campaigns to promote participation in recycling programs. Such policies will not only accelerate Hungary's transition towards a circular economy but also position the country as a leader in sustainable resource management within the EU.