The Role of E-Waste in Sustainable Mineral Resource Management

Abstract

This paper analyses the role of electronic waste (E-waste) as a secondary source of critical and precious minerals, addressing the challenges and opportunities in transitioning towards a circular economy (CE) for electronics. The surging global demand for these essential materials, driven by technological advancements and renewable energy infrastructure, necessitates alternative supply strategies due to the depletion of natural reserves and the environmental degradation associated with primary mining. E-waste contains a rich concentration of valuable metals, such as gold, silver, and platinum, making its recovery a promising solution aligned with CE principles, which can mitigate environmental impacts and ensure long-term material availability. This paper examines the environmental, economic, and technological aspects of E-waste recovery, focusing on core processes such as physical and mechanical separation, pyrometallurgical, hydrometallurgical, bio-metallurgical, and electrochemical techniques. It explores innovative strategies to improve material recovery efficiency and sustainability, with consideration of evolving regulatory frameworks, technological advancements, and stakeholder engagement. The analysis highlights that e-waste, particularly printed circuit boards, can contain 40–800 times more gold than mined ore, with 1000–3000 g of gold per tonne compared to 5–10 g per tonne in traditional ores. Recovery costs using advanced E-waste recycling technologies range between $10,000–$20,000 USD per kilogram of gold, significantly lower than the $30,000–$50,000 USD per kilogram in primary mining. Globally, over 50 million tonnes of E-waste are generated annually, yet less than 20% is formally recycled. Efficient recycling methods can recover up to 95% of base and precious metals under optimized conditions. The paper argues that E-waste recycling presents a viable pathway to conserve critical raw materials, reduce environmental degradation, and enhance circular economic resilience. However, it also emphasizes persistent challenges—including high initial investment, technological limitations in developing regions, and regulatory fragmentation—that must be addressed for scalable adoption.

1. Introduction

The global demand for critical and precious minerals has surged in recent decades, driven by rapid industrialization, advancements in digital technologies, and the expansion of renewable energy infrastructure. However, the depletion of natural reserves of these essential materials poses a significant challenge to long-term resource sustainability. Figure 1 (data from [1]) illustrates the available natural reserves, annual consumption rates, and projected depletion timelines for key metals such as gold, silver, and platinum. Figure 1A shows that for each metal, the underground reserves significantly exceed the annual consumption. Notably, copper has the highest available quantity and annual usage, while platinum has the lowest annual consumption. This suggests varying levels of resource abundance and demand across the metals. The depletion rates (Figure 1B) are derived from the available quantities and annual consumption rates shown in Figure 1A. Specifically, copper, which has the highest available quantity and annual consumption (Figure 1A), also exhibits the highest depletion rate (Figure 1B). Conversely, gold, with relatively lower values (Figure 1A), has the lowest depletion rate (Figure 1B). The finite nature of these resources necessitates a paradigm shift towards alternative supply strategies to mitigate supply chain vulnerabilities and environmental degradation associated with primary mining operations.

One promising solution is the recovery of critical and precious minerals from electronic waste (E-waste), a concept aligned with the principles of the circular economy (CE). E-waste contains a rich concentration of valuable metals, making it a viable secondary source that reduces reliance on virgin mineral extraction. The sustainable management of E-waste through enhanced recycling and resource recovery can contribute significantly to mitigating environmental impacts while ensuring long-term material availability [2,3]. Recent advancements in urban mining technologies, particularly in hydrometallurgical and bio-metallurgical recovery processes, have demonstrated substantial potential for extracting valuable metals from discarded electronic devices, reinforcing the viability of E-waste as a key component of sustainable resource management [4]. The environmental ramifications of primary mineral extraction, including habitat destruction, soil contamination, and greenhouse gas emissions, have intensified the need for alternative resource pathways [5,6]. In this context, E-waste recycling has emerged as a sustainable and economically viable alternative, reducing environmental degradation while enhancing resource security and economic resilience [7,8,9].

E-waste recovery aligns with international sustainability goals by reducing landfill waste, conserving natural resources, and minimizing carbon footprints associated with traditional mining practices [10,11,12,13]. Specifically, E-waste recovery aligns closely with several United Nations Sustainable Development Goals (SDGs) by addressing critical environmental and resource challenges. Primarily, it supports SDG 12 (Responsible Consumption and Production) by promoting recycling, reducing landfill waste, and conserving valuable materials through circular economy practices. It also contributes to SDG 13 (Climate Action) by minimizing the carbon footprint associated with traditional mining and raw material extraction, which are energy-intensive and polluting processes. Additionally, E-waste recovery enhances urban sustainability in line with SDG 11 (Sustainable Cities and Communities) by improving waste management systems and reducing environmental degradation in urban areas. From an industrial perspective, it advances SDG 9 (Industry, Innovation and Infrastructure) by encouraging innovation in green technologies and sustainable manufacturing practices. Finally, by creating opportunities for green jobs and fostering resource-efficient growth, E-waste recovery contributes to SDG 8 (Decent Work and Economic Growth), supporting the transition toward a more sustainable and inclusive economy.

Transitioning to a CE model requires an integrated approach that emphasizes material recovery, regulatory frameworks, economic incentives, technological innovations, and stakeholders’ engagements [12,13]. The rapid expansion of digital technologies and electronic consumption has led to an unprecedented surge in E-waste generation [14,15,16]. Between 2011 and 2023, global E-waste production increased from 35.8 million metric tons (Mt) to 61.3 Mt, with projections estimating it will reach 74.7 Mt by 2030 [4]. This trend underscores the urgent need for enhanced recycling efforts, as current global recycling rates remain alarmingly low. In 2019, globally, only 9.3 Mt of the 53.6 Mt of generated E-waste was recycled, representing just 17.4% of the total volume, highlighting a significant gap between waste generation and material recovery efforts [4].

This paper provides a comprehensive analysis of E-waste as a secondary source of critical minerals, examining the environmental, economic, and technological aspects of E-waste recovery. It explores the benefits and challenges associated with transitioning to a CE and investigates innovative strategies for improving material recovery and sustainability. Therefore, this paper is intended to find an answer to the following research question “How can technological advancements, policy interventions, and stakeholder engagement be synergistically leveraged to bridge the existing gaps in E-waste management, thereby optimizing the recovery of critical and precious minerals and fostering a resilient CE for electronics?” By addressing current inefficiencies in E-waste recycling systems and proposing pathways for sustainable resource management, this study aims to contribute to the broader discourse on enhancing sustainability and CE principles in mineral resource utilization.

2. Novelty

The novelty of this study lies in its synergistic and comprehensive analysis of the role of E-waste as a secondary source of critical and precious minerals. While the individual aspects of E-waste recovery, such as technological advancements, policy interventions, and stakeholder engagement, are discussed in existing literature, this study aims to understand how these three domains can be synergistically leveraged to optimize the recovery of critical and precious minerals and foster a resilient CE for electronics (Figure 2). The specific points highlighting this novelty are:

• The focused approach on the interplay between the three domains, to achieve specific outcomes (optimized mineral recovery and a resilient CE, is a central novel aspect.
• The paper provides a comprehensive analysis by examining the environmental, economic, and technological aspects of E-waste recovery. It also investigates innovative strategies for improving material recovery and sustainability, considering regulatory frameworks, technological innovations, and economic incentives. This multi-faceted approach to understanding the challenges and opportunities in transitioning to a CE for electronics, with a specific focus on mineral recovery, adds to its novelty.
• The manuscript highlights the significant gap between E-waste generation and material recovery efforts and seeks to propose pathways for sustainable resource management by addressing current inefficiencies in E-waste recycling systems. This focus on identifying and proposing solutions to existing gaps contributes to the novelty.
• The study aims to contribute to the broader discourse on enhancing sustainability and CE principles in mineral resource utilization. This ambition to not only analyze E-waste but also to link it to wider sustainability and CE principles in the context of mineral resources suggests a novel contribution beyond a narrow technical analysis.

In summary, the novelty of this manuscript lies in its holistic approach to understanding how technological advancements, policy interventions, and stakeholder engagement can work together to significantly improve critical and precious mineral recovery from E-waste and establish a more resilient CE for the electronics sector. It moves beyond examining these aspects in isolation and focuses on their synergistic potential to address the pressing challenges in E-waste management and resource sustainability.

3. Methodology and Data Analysis

3.1. Identification of Sources

The scoping review followed the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) (2018 version) framework to ensure methodological transparency and consistency. An extensive literature search was conducted across multiple academic databases, including Scopus, Web of Science, and Google Scholar, focusing on scholarly publications related to E-waste management and critical mineral recovery. The search strategy combined key terms such as “E-waste”, “critical minerals”, “recycling technologies”, “circular economy”, “policy frameworks”, and “stakeholder engagements.” Additional sources were identified through backward citation tracking and expert consultations to ensure comprehensive coverage. The search was limited to publications in English and primarily focused on peer-reviewed articles, conference papers, and reviews.

3.2. Screening and Eligibility Analysis

All retrieved records (from 2012 to 2024) were imported into a reference management system where duplicates were removed. Titles and abstracts were screened against predefined inclusion criteria: (a) relevance to E-waste management or critical/precious mineral recovery, (b) focus on technologies, environmental impacts, policy, consumer behavior and awareness or circular economy frameworks, and (c) clear methodological basis. Publications were excluded if they focused solely on general waste management, lacked empirical or technical content, or were non-English documents. The remaining articles underwent full-text review to confirm their eligibility. A total of 145 publications were included in the final analysis.

3.3. Data Analysis and Synthesis of Results

Each publication was classified into one of eight thematic categories derived from recurrent patterns in the literature: (1) mineral recovery technologies from e-waste, (2) critical and precious minerals, (3) sustainability and environmental impacts, (4) industrial applications of specific metals, (5) consumer behavior and awareness, (6) policy and legal frameworks, (7) emerging technologies and automation, and (8) general E-waste management and CE. The results of the review are visually summarized using a PRISMA-ScR-inspired flow chart, detailing the identification, screening, eligibility, and inclusion phases. The flow chart (Figure 3) illustrates the progressive refinement of sources from initial retrieval to final selection.

Distribution of publications across various thematic areas within the field of E-waste management and mineral recovery is presented in Figure 4. The data reveals that “Mineral Recovery Technologies from E-waste” is the most extensively researched area, with 44 publications. This indicates a significant academic and industrial focus on developing and optimizing methods to extract valuable minerals from electronic waste. Closely following is the category of “Critical and Precious Minerals”, which has 36 publications. This reflects a strong interest in recovering high-value elements such as gold, palladium, and rare earth metals from discarded electronics. These two leading categories suggest that much of the current research effort is directed toward maximizing resource recovery from E-waste.

The environmental and sustainability aspects are also well represented. “Sustainability and Environmental Impacts of E-waste and Mineral Extraction” has 15 publications, pointing to an active interest in understanding and mitigating the ecological consequences of both E-waste processing and traditional mining activities. Similarly, the topic of “Industrial Applications and Production of Specific Metals” has 14 publications, focusing on how the recovered materials are utilized in various industrial processes. Both “Consumer Behavior, Awareness, and Participation in E-waste Recycling” and “Policy, Regulation, and Legal Frameworks for E-waste Management” have 13 publications each. This highlights a moderate level of research in the areas of public engagement and the institutional and legal structures governing E-waste practices, which are crucial for successful implementation of recycling initiatives. On the other hand, “Emerging Technologies and Automation in E-waste Management” and “General E-waste Management and Circular Economy” are the least explored categories, each with only 5 publications. These results suggest that there may be opportunities for future research in innovative technologies and in developing systemic CE models for E-waste.

In summary, the chart illustrates a research landscape heavily oriented toward technological and material recovery, with relatively less emphasis on automation, CE integration, and behavioral or regulatory aspects. This highlights potential gaps that could be addressed to create a more holistic approach to E-waste management.

4. Critical and Precious Minerals

4.1. Industrial Significance, Major Producers, and Potential Environmental Impact from Primary Resource Extraction Processes

Critical minerals, including lithium, cobalt, and rare earth elements (REEs), are vital for renewable energy, electronics, and defense sectors. Precious metals like gold, silver, and platinum are essential for electronic devices and high-performance applications such as batteries and semiconductors [16,17]. The term “critical metals” refers to those essential for clean energy technologies, including wind and geothermal turbines [18], solar panels, electric vehicles [19], and hydrogen production for energy storage [20]. Their criticality is determined by three factors: natural scarcity, supply chain risks, and economic and environmental feasibility of extraction (

Table 1. Critical and precious minerals: Properties, industrial applications, major producers and current supply risk (revised after [17]).

Element	Important Properties	Industrial Utilization	Major Producers	Supply Risk	References
Aluminum	Conductive, flexible, durable, recycleable	Aerospace, defense, and infrastructure	China, India	Moderate	[26]
Antimony	Flame proofing compound	Flame retardants, batteries, and alloys	China, India	High	[27,28]
Cadmium	Fatigue and corrosion resistive	Solar panels and batteries	China, South Korea	High	[29,30]
Caesium	Higly reactive, pyrophoric	Atomic clocks, drilling fluids, and electronics	Canada, Australia	High	[31,32]
Chromite	Durability, hardness, wear resistance	Source of chromium, used in stainless steel and alloys	South Africa, Turkey	Very high	[33]
Cobalt	Wear resistance, high strength, magnetic	Batteries, superalloys, and magnets	Democratic Republic of Congo, Indonesia	High	[34,35]
Gallium	Conductive	Semiconductors and LEDs	China, Japan	High	[36]
Gold	Inert, high conductivity	Jewelry, electronics, and investment	China, Australia	Moderate	[37,38,39]
Indium	High conductivity, corrosion resistive, low melting point	Touchscreens, solar panels, and LCDs	China, South Korea	High	[40,41,42]
Lithium	Resistance to abrasion in synthetic rubber	Batteries and energy storage	Chile, Australia	High	[43,44]
Manganese	Corrosion resistive	Steel production and batteries	China, South Africa	Moderate	[45,46]
Molybdenum	Strength, corrosion resistive, conductivity	Steel alloys and catalysts	China, Chile	Moderate	[47,48]
Nickel	Corrosion resistive, toughness	Batteries, stainless steel, and alloys	Indonesia, Philippines	Moderate	[49,50]
Platinum Group Elements (PGEs)	Hardness, corrosion resitive, high melting points	Catalytic converters and hydrogen fuel cells	South Africa, Russia	Very high	[51,52]
Rare Earth Elements (REEs)	Magnetic, phosphorescent	Electronics, magnets, and defense applications	China, USA	Very high	[53,54]
Selenium	Photoconductive	Solar panels and electronics	China, Japan	High	[55,56]
Silver	High conductivity, antibacterial properties	Jewelry, electronics, and investment	Mexico, China	Moderate	[57]
Tellurium	Piezoelectric	Solar cells and thermoelectrics	China, Japan	High	[58,59]
Tin	Corrosion resistive, light weight	Soldering and electronics	China, Indonesia	Moderate	[60,61]
Titanium	Hardness, resistive, light weight, chemically inert	Aerospace, medical, and pigments	China, Mozambique	Moderate	[62,63]
Tungsten	High melting and boiling points, high density	Cutting tools, defense, and electronics	China, Russia	High	[64]
Uranium	High density, radioactive	Nuclear power and defense applications	Kasakhstan, Namibia	Moderate	[65]
Vanadium	Toughness, shock and vibration resistance	Steel alloys and redox flow batteries	China, Russia	Moderate	[66,67]
Zinc	Corrosion resistive	Galvanization and alloys	China, Peru	Low	[68,69]

; revised after [17]. Global demand for critical metals has surged over the past decade due to population growth and their role in green energy technologies [21,22,23,24,25]. In year 2023, clean energy applications drove strong demand increases, with lithium consumption rising by 30% and other key minerals like nickel, cobalt, graphite, and REEs growing by 8–15% [16].

The supply chains of critical minerals are highly concentrated in a few regions, leading to geopolitical vulnerabilities and market volatility (Table 1; revised after [17]). China, for instance, dominates the production and processing of REEs, while cobalt mining is largely controlled by operations in the Democratic Republic of Congo. This dependence on a limited number of suppliers poses a significant risk to technological and economic stability.

The extraction of critical and precious minerals from primary sources involves extensive land use, high energy consumption, and pollution [6,25]. Mining operations can lead to deforestation, soil degradation, and water contamination, often impacting vulnerable communities. The push for sustainable sourcing emphasizes the need to recover these materials from secondary sources such as E-waste to reduce environmental harm and promote ethical supply chains.

4.2. E-Waste as a Sustainable Resource for Critical and Precious Minerals

4.2.1. Secondary Resource Potentials

The accelerating demand for electronics, electric vehicles, and renewable energy technologies has increased the consumption of critical minerals. However, many of these resources are finite, and their depletion raises concerns about long-term availability [70]. E-waste recycling offers a means to supplement supply, ensuring the continued development of advanced technologies without exacerbating raw material scarcity [71,72]. E-waste contains a diverse array of valuable minerals, including copper, gold, silver, platinum, lithium, and REEs [73]. Figure 5 (data from [74]) provides a comprehensive overview of the distribution of metals in E-waste in year 2022 worldwide, categorized into total metals, other metals, and precious metals. These data highlight the quantities of various metals present in discarded electronics and their respective recycling rates, revealing significant disparities in recovery efficiency across different categories. Figure 5A (data from [74]) illustrates the presence of total metals in E-waste, measured in billion kilograms (Kg). Iron (Fe) is the most abundant, accounting for 24 billion Kg, followed by aluminum (Al) at 4 billion Kg and copper (Cu) at 2 billion Kg. Smaller quantities of nickel (Ni) (0.52 billion Kg) and other metals (0.46 billion Kg) are also present. These metals constitute the largest fraction of E-waste materials, and their relatively high recycling rate of 60% suggests the existence of well-established recovery processes, particularly for iron and aluminum, which are widely used in infrastructure and electronics manufacturing.

The presence of other metals (0.46 billion Kg) in E-waste, measured in million kilograms (Kg) is shown in Figure 5B (data from [74]). Among them, zinc (Zn) is the most prevalent at 280 million Kg, followed by lead (Pb) (70 million Kg), tin (Sn) (44 million Kg), cobalt (Co) (34 million Kg), and antimony (Sb) (28 million Kg). These metals are critical for various industrial applications, including batteries, soldering, and electronic components. However, their recycling rate is alarmingly low at just 4%, indicating significant inefficiencies in current recovery technologies. This low rate can be attributed to the dispersed nature of these metals in complex electronic waste streams, making extraction challenging and often economically unviable.

The presence of precious metals (2 million Kg) in E-waste, measured in thousand kilograms (Kg) is shown in Figure 5C (data from [74]). Silver (Ag) leads at 1200 thousand Kg, followed by gold (Au) at 270 thousand Kg and palladium (Pd) at 120 thousand Kg. Additionally, smaller quantities of osmium (Os) (12 thousand Kg) and platinum group metals such as praseodymium (Pr), iridium (Ir), rhodium (Rh), and ruthenium (Ru) (9 thousand Kg) are also present. Despite their relatively small quantities compared to bulk metals, these elements hold significant economic value. The recycling rate for precious metals stands at 20%, reflecting a moderate recovery level. Specialized hydrometallurgical and pyrometallurgical techniques enable the extraction of Au, Ag, and Pd, yet substantial losses still occur, emphasizing the need for enhanced E-waste recovery infrastructure.

In summary, Figure 5 (data from [74]) underscores the urgent need to improve E-waste recycling technologies and policies. While total metals enjoy a relatively high recovery rate, other metals remain vastly underutilized, and even precious metals—despite their value—are not being recycled at optimal levels. Developing advanced extraction methods, strengthening regulatory frameworks, and creating economic incentives for E-waste recycling are critical steps toward enhancing resource sustainability and minimizing environmental impacts.

4.2.2. Environmental Benefits

Recycling E-waste reduces reliance on traditional mining, which is linked to extensive environmental degradation, greenhouse gas emissions, and habitat destruction [6,75]. Improper E-waste management results in the annual release of approximately 58 thousand kg of mercury and 45 million kg of plastics containing brominated flame retardants into the environment [74]. Effective E-waste management mitigates landfill accumulation, prevents hazardous substances from contaminating soil and water, and conserves natural resources [76]. Furthermore, the recovery of secondary raw materials through E-waste recycling has prevented the extraction of 900 billion kg of ore and avoided 52 billion kg of CO₂-equivalent emissions [74]. Additionally, metal recovery from E-waste generally requires less energy than primary ore extraction, contributing to a reduced carbon footprint.

4.2.3. Economic Benefits

The estimated potential value of secondary raw materials in E-waste highlights the economic significance of metal recovery from discarded electronics. For example, in year 2022, the overall gross value of the metals contained in E-waste, worldwide, was estimated at USD 91 billion (Figure 6; data from [74]). Among these, copper (Cu) holds the highest value at $19 billion, reflecting its essential role in wiring and circuit boards. Following closely, iron (Fe) and gold (Au) are valued at $16 billion and $15 billion, respectively. While iron is widely used in structural components, gold’s high value stems from its role in high-performance electronic circuits. Nickel (Ni) and aluminum (Al) also contribute significantly to the overall value, with estimated recoverable amounts worth $14 billion and $11 billion, respectively. Nickel is commonly found in batteries and specialized alloys, while aluminum is used in casings and heat dissipation components. Additionally, palladium (Pd), a crucial element in electronic connectors and catalytic applications, holds a potential value of $8 billion. Other metals, including cobalt (Co), tin (Sn), and silver (Ag), represent lower but still notable values at $2.3 billion, $1.4 billion, and $0.9 billion, respectively. Cobalt is primarily used in lithium-ion batteries, tin in soldering applications, and silver in high-conductivity components. Overall, this data (Figure 6; data from [74]) underscores the immense economic opportunity in E-waste recycling. Recovering these valuable metals not only supports material sustainability but also plays a crucial role in advancing the CE by reducing reliance on virgin resources and minimizing environmental impact.

Moreover, E-waste recycling creates economic opportunities by generating jobs in collection, processing, and advanced material recovery [77]. As demand for critical and precious minerals rises, urban mining from E-waste can provide a cost-effective alternative to raw material extraction, especially in regions lacking natural mineral deposits. With advances in refining techniques and economies of scale, the profitability of EE-waste recovery is expected to improve, fostering long-term sustainability in the electronics sector.

5. Technologies for Mineral Recovery from E-Waste

Recovering valuable minerals from E-waste is crucial for resource efficiency, sustainability, and reducing environmental impact. Several technologies are used for mineral recovery, each with distinct mechanisms and advantages [9,11,12,78,79,80,81,82,83,84,85,86]. The primary methods include physical and mechanical separation, hydrometallurgical processes, pyrometallurgical processes, bio-metallurgy, and electrochemical processes.

5.1. Physical and Mechanical Separation

Physical and mechanical separation processes are the first step in E-waste recycling, aiming to extract valuable materials based on their physical properties without chemical modification [9,12]. These methods include shredding and crushing to break down E-waste into smaller pieces, followed by magnetic separation to remove ferromagnetic materials like iron, nickel, and cobalt. Eddy current separation is employed to recover non-ferrous metals such as copper and aluminum, while density separation (gravity and air classification) separates plastics, glass, and metals based on their weight differences. Additionally, electrostatic separation leverages variations in electrical conductivity to separate conductive metals from non-conductive materials.

Figure 7 illustrates a series of general physical and mechanical separation processes commonly employed in materials recovery and waste management. The overall flow demonstrates how mixed materials are progressively separated into more homogeneous streams based on their physical properties, leading to recovery or disposal. The process typically begins with initial material handling, which the figure broadly categorizes into processes like “Sorty Mixed streams”, “Dishetal Crushing”, “Distding Crusing”, and “Fror Milling.” These initial steps involve manual or automated sorting and dismantling to segregate larger items and different material types, along with preliminary mechanical processing such as crushing and milling to reduce the size of the materials. This size reduction is crucial for the efficiency of subsequent separation techniques. Following the initial mechanical processing, the figure depicts several advanced separation technologies. These include shredding and further size reduction steps, which prepare the materials for more precise separation. Critical to metal recovery are Eddy Current Separation, which effectively separates non-ferrous metals like aluminum by using rapidly changing magnetic fields, and Magnetic Separation, which uses strong magnets to extract ferrous metals such as iron and steel from the material stream. The figure also highlights Density Separation (including “Density—Air floattion”), where materials are separated based on their specific gravity, often using air classifiers or liquid media to differentiate light plastics from heavier materials like glass or denser plastics. Additionally, Electrostatic Separation is shown, which separates materials based on their electrical conductivity after being charged, commonly used for plastics or fine particles. The ultimate outcome of these processes is the segregation of various “Materildy”, “Recreations”, and other fractions, leading to either further processing, recycling, or final “Dispale” (Disposal) for unrecoverable waste.

These processes are shown in

Table 2. General physical and mechanical separation processes with an example from the Information Technology and Telecommunication sector.

General Processes		An Example for IT and Telecommunication Equipment Separation Processes
Steps	Products	Manual Processing Step(s)	Mechanical Processing Step(s)	Products
A. Sorting and Dismantling	Separation of reusable parts	Sorting		Capacitors, tuners, batteries
B. Mechanical Processing (size reduction and sorting)	Separation of metals, plastics, etc.		Crushing
C. Eddy Current Separation	Separation of nonferrous metals	Sorting		Valuable and hazardous components
D. Magnetic Separation	Separation of ferrous metals		Shredding
E. Density Separation	Separation of plastics	Sorting		Valuable and hazardous components
F. Electrostatic Separation	Separation of conductive metals from non-conductive materials		Shredding
G. Disposal	Landfilling		Eddy current separation	Nonferrous metals
			Magnetic separation	Ferrous metals

with specific example for Information Technology (IT) and telecommunication equipment. A typical physical–mechanical treatment plant for IT and telecommunication equipment follows a sequential process. Upon arrival, materials are sorted and cleaned by removing hazardous substances (e.g., ink cartridges, mercury-containing switches, and various batteries) and recovering valuable components like hard drives and printed circuit boards (PCBs). An initial mechanical treatment breaks casings to expose internal parts, followed by manual selection of valuable and hazardous components. The remaining material is shredded and undergoes a second manual sorting cycle before further shredding reduces it to a few centimeters. Finally, the shredded material is processed through eddy currents to extract non-ferrous metals, while magnetic separation isolates ferrous metals.

Notably, physical and mechanical methods for E-waste recycling, while cost-effective and environmentally friendly for initial processing, fall short in recovering fine or mixed metal particles and extracting metals from complex chemical compounds. Achieving high liberation of metals often requires particle sizes as small as 75 microns, a level difficult and energy-intensive to reach mechanically, leading to inefficient separation of fine and mixed metal streams. Furthermore, these methods cannot break the chemical bonds within alloys, oxides, or the integrated structures of printed circuit boards (PCBs), which can be up to 70% unrecyclable by physical means alone. This inherent limitation necessitates subsequent hydrometallurgical or pyrometallurgical treatments for comprehensive metal recovery and the safe management of hazardous substances.

5.2. Pyrometallurgical Processes

Pyrometallurgy employs high-temperature treatments to extract and refine metals from E-waste [87,88,89,90]. The most common method is smelting, where E-waste is melted in furnaces to separate metals based on their densities. Roasting is another technique that converts metal compounds into oxides or sulfides for further refining. In more advanced applications, plasma arc furnaces use high-energy plasma to extract metals, while volatilization allows for the recovery of certain metals like mercury and zinc through controlled evaporation.

Table 3. Pyrometallurgical processes.

Pyrometallurgical Processes	Description
❖ Incineration	E-waste is incinerated at high temperatures in a controlled environment, breaking down organic materials and combustibles while leaving metal-rich ash.
❖ Smelting	Ashes or shredded E-waste are melted in high-temperature furnaces, allowing metals to separate from non-metallic materials due to their lower melting points. Valuable metals like copper, lead, and precious metals are collected in molten form.
❖ Roasting	Metal compounds are converted into oxides or sulfides for further refining
❖ Plasma arc furnaces	Metals are extracted using high-energy plasma.
❖ Volatilization	Certain metals like mercury and zinc are recovered through controlled evaporation
❖ Cupellation	The metal-rich material is heated in a cupel (a porous container) with a blast of air, which oxidizes impurities and leaves behind the precious metals. It is used to recover precious metals like gold and silver.

lists the various pyrometallurgical processes.

Figure 8 provides a comprehensive visual overview of various pyrometallurgical Processes. The figure is organized to showcase several distinct operations, each involving significant heat application. One prominent process depicted is Incineration, illustrated as the combustion of waste materials at high temperatures, often for volume reduction or energy recovery. Alongside this, smelting is clearly shown as a process for extracting metals from ores by melting them in a furnace, separating the metal from impurities in a molten state. The figure also highlights roasting, which involves heating sulfide ores in the presence of air to oxidize sulfides into oxides and remove sulfur, preparing the material for subsequent smelting or other processes. Further advanced techniques are also illustrated. Plasma Arc Furnaces are presented as systems utilizing high-temperature plasma to melt and refine materials, offering precise control and very high temperatures. Volatilization is depicted as the vaporization of metals or other components during heating, often used to separate components with different boiling points. Finally, Cupellation is shown as a refining process, typically for precious metals like gold or silver, where impurities are oxidized and absorbed by a porous material (a cupel) at high temperatures, leaving the purified metal. Together, these processes represent the diverse applications of high-temperature metallurgy in transforming raw materials and waste into valuable metallic products.

Pyrometallurgical methods, such as smelting and roasting, provide high recovery efficiency and fast processing by using high temperatures to extract metals from E-waste [90]. For example, copper smelting in a blast furnace effectively recovers copper, gold, and silver from PCBs. Similarly, lead smelting extracts lead from batteries, while plasma arc furnaces refine precious metals from E-waste. However, these methods demand substantial energy, as furnaces must maintain temperatures exceeding 1200 °C. Additionally, they release air pollutants like dioxins, furans, and heavy metal vapors, requiring advanced filtration systems such as baghouse filters, electrostatic precipitators, and wet scrubbers to minimize environmental impact.

Pre-treatment is crucial to remove plastics and hazardous substances that could release toxic emissions during processing. For instance, PCBs contain brominated flame retardants, which, when burned, generate harmful dioxins. Removing these plastics beforehand reduces the formation of hazardous compounds and improves metal recovery efficiency. Similarly, mercury switches and cadmium-containing components must be extracted to prevent toxic gas emissions during high-temperature processing. Thus, while pyrometallurgical techniques offer efficient metal recovery, they necessitate careful pre-processing and emission control measures to mitigate environmental and health risks.

5.3. Hydrometallurgical Processes

Hydrometallurgical methods involve using aqueous solutions to dissolve and extract metals from E-waste [9,91,92,93,94,95,96,97,98,99]. The process (

Table 4. Hydrometallurgical processes.

Hydrometallurgical Processes	Description
❖ Leaching	Chemicals such as sulfuric acid (H2SO4), nitric acid, or cyanide (CN−) are used to dissolve specific metals. H2SO4 is used to extract base metals like Zn, Fe, Co, Pb, Al, and Cu. HNO3 is used to extract base metals (including REE) and noble metals (i.e., Ag, Pd, Cu, Hg). Cyanide solutions are used especially for gold recovery, under strictly alkaline conditions in the presence of oxygen
❖ Ammonia leaching	It is sometimes used for selective recovery of copper and nickel. With higher reduction potential metals, i.e., Cu and Ag, its action can be empowered by adding oxidants such as H2O2, (NH4)2S2O8, or others.
❖ Solvent extraction (SX)	Solvent extraction selectively recovers specific metals using organic solvents that bind to target metal ions. In copper recovery, the leachate containing dissolved copper ions is mixed with an organic solvent, such as a hydroxyoxime-based extractant, which selectively binds to copper. The copper-laden solvent is then separated and stripped using sulfuric acid to regenerate copper sulfate, which can be further processed into pure copper via electrowinning. This method is also used to extract REEs from E-waste, such as neodymium and dysprosium from magnets in hard drives.
❖ Ion exchange	Ion exchange relies on resins to capture specific metal ions from the solution. Gold recovery from E-waste uses strong-base anion exchange resins that selectively adsorb gold cyanide complexes from the leachate. The resin is then stripped with a suitable eluent, such as thiourea or sodium thiosulfate, releasing gold for further refining. Platinum group metals (PGMs) like palladium and platinum from catalytic converters in E-waste can be extracted using chelating resins designed to bind specifically to these elements.
❖ Precipitation	Precipitation recovers metals by adjusting the pH of the solution using reagents that cause metal hydroxides or sulfides to form. For examples: Gold precipitation: Sodium metabisulfite or ferrous sulfate is added to a gold-bearing solution, reducing gold ions to solid elemental gold; Nickel and cobalt recovery: By adding sodium hydroxide, nickel and cobalt precipitate as hydroxides, which can be further refined; and Lead and zinc removal: Sulfide precipitation using hydrogen sulfide gas or sodium sulfide helps recover lead and zinc as insoluble sulfides from E-waste processing solutions.

) typically begins with leaching, where chemicals such as sulfuric acid (H₂SO₄), nitric acid (HNO₃), or cyanide dissolve specific metals. Ammonia leaching is sometimes used for selective recovery of copper and nickel. Once the metals are in solution, solvent extraction (SX) employs organic solvents to selectively recover valuable metals, while ion exchange uses resins to capture specific metal ions. Finally, metals are recovered through precipitation, where reagents like sodium hydroxide help extract metals by adjusting the pH. Hydrometallurgy is an energy-efficient and highly selective method for recovering metals like gold, silver, and copper. While it produces lower emissions than pyrometallurgy, it relies on hazardous chemicals and requires extensive wastewater treatment. Effective reagent selection and proper waste management are crucial to minimizing environmental impact and operational costs.

For instance, Figure 9 provides a detailed look at the Solvent Extraction process for recovering metals, with a focus on copper and its applicability to REEs. The process begins with leaching and mixing, where a leachate solution, laden with dissolved copper, is introduced into a mixer-settler system. Here, it’s combined with a specialized organic solvent, often a hydroxyoxime-based extractant, which selectively binds to the copper ions. Following this, phase separation occurs. In the settler, the now copper-rich organic solvent separates from the aqueous raffinate, which has a reduced copper content. The copper-laden organic phase then moves to the stripping stage. In this crucial step, the organic solvent is mixed with a sulfuric acid solution. This causes the copper ions to transfer back into the aqueous phase, forming a purified copper sulfate solution and regenerating the organic solvent for reuse in the initial mixing stage. Finally, the copper sulfate solution proceeds to electrowinning. An electric current is passed through the solution, causing pure copper metal to deposit onto a cathode. The figure also highlights the versatility of this method by indicating its use for extracting REEs, such as neodymium and dysprosium, commonly found in E-waste magnets. This cyclical process efficiently extracts target metals from impure solutions, purifies them, and recovers them in a usable form, all while recycling the key solvent component.

Notably, hydrometallurgical methods demonstrate high efficiency in recovering critical minerals from e-waste. For instance, studies have shown that acid leaching and solvent extraction can achieve up to 95% metal recovery efficiency for various metals found in e-waste. Specifically, for valuable critical minerals, reported recovery rates are impressive: lithium extraction from spent Li-ion batteries can reach 100%, with cobalt recovery nearing 99.9% under optimized conditions using specific acid mixtures. For precious metals, hydrometallurgical routes have successfully recovered over 90% of gold from E-waste materials with high copper content using thiourea leaching, and 99.9% of cobalt has been achieved through selective solvent extraction processes.

The strength of hydrometallurgy lies in its ability to selectively extract specific metals, even from complex mixtures and chemical compounds that mechanical methods cannot process. This allows for the targeted recovery of critical REEs, precious metals (e.g., gold, silver, palladium), and battery metals (e.g., lithium, cobalt, nickel), which are crucial for high-tech industries. While these processes can generate wastewater and require chemical reagents, ongoing research focuses on developing greener solvents (like ionic liquids and deep eutectic solvents) and optimizing processes to reduce environmental impact and improve overall sustainability, further solidifying hydrometallurgy’s role as a leading method for critical mineral recovery from e-waste.

5.4. Bio-Metallurgy

Biological methods, collectively known as bio-metallurgy, use microbes or plants to extract metals from E-waste in an eco-friendly manner [100,101,102]. One of the most promising techniques is bioleaching, which utilizes bacteria such as Acidithiobacillus ferrooxidans and fungi to break down E-waste and dissolve valuable metals [103,104,105,106,107]. For example, Nithya et al. [106] used Pseudomonas balearica SAE1 to extract gold and silver and achieved a recovery rate of 68.5%, and 33.8%, respectively. Another approach, phyto-mining, involves using plants to absorb and accumulate metals from shredded E-waste [108,109]. These processes are environmentally sustainable and have low energy consumption compared to traditional metallurgical techniques. However, bio-metallurgy is slow and requires specific conditions for microbial activity, making it less viable for large-scale industrial applications. Despite these challenges, ongoing research aims to optimize microbial efficiency and improve scalability.

5.5. Electrochemical Processes

Electrochemical methods recover metals through redox reactions driven by electric currents. One widely used technique is electrowinning, which extracts metals such as gold, silver, and copper by reducing metal ions from solution onto an electrode [109,110]. Figure 10 provides an illustration for three main stages involved in recovering copper from e-waste: bioleaching, solvent extraction (SX), and electrowinning (EW). The process kicks off with bioleaching, where E-waste is introduced into a system containing various microorganisms. These microbes facilitate the dissolution of copper from the waste, resulting in a copper-rich leachate. Next, this leachate moves on to the solvent extraction stage. Here, the copper-rich solution is mixed with an organic solvent, which selectively binds to the copper ions. The figure shows the copper ions transferring from the aqueous leachate into the organic phase, effectively separating them from other impurities. Following this, the copper-laden organic solvent (or the stripped copper solution derived from it) proceeds to the final stage: electrowinning. In the electrowinning cell, an electrical current is applied to the solution. This causes pure copper metal to deposit onto a cathode, demonstrating the successful recovery of copper in a solid, usable form. This entire process showcases an efficient and environmentally conscious method for extracting valuable copper from electronic waste, combining biological, chemical, and electrochemical techniques.

For instance, Murali et al. [110] successfully recovered copper from E-waste through a bioleaching process followed by solvent extraction (SX) and electrowinning (EW). After copper recovery, precious metals (Au and Ag) were extracted using a thiosulfate process, followed by resin adsorption, stripping, and either electrowinning or cementation. Under optimized conditions, more than 94% of copper and less than 10% of iron were transferred from the E-waste leach solution during the loading phase, with a 92% stripping efficiency from the loaded organic phase. Electrowinning of the stripped solution produced electrodeposits with 99% purity and a current efficiency of 94.5%. Optimal conditions for achieving approximately 87% gold leaching recovery included 111 mM thiosulfate, 30.0 mM copper (II), and 0.32 M ammonia. The electrowinning tests further demonstrated that the gold fraction reached 81% when applying an electrode potential of −600 mV Ag/AgCl.

Electrorefining is another electrochemical process that purifies metals by dissolving impure metal at the anode and depositing pure metal at the cathode. For example, Mahyapour and Mohammadnejad [111] reported that using an anode composition of 75% gold, an electrolyte with an ionic concentration of 2 M, a process temperature of 25 °C, and a specific cathode current of 0.02 A/cm², resulted in the production of cathode gold with a purity of 95.3% when the electrolyte gold concentration was below 1 g/L. Additionally, Italimpianti refining plants in Italy can produce gold with a purity of 999.9/1000 from an initial composition of 900/1000, with a maximum silver content of 3% and total platinum group metals (PGM) of 0.1% [112].

Another electrochemical approach, electrocoagulation, utilizes an electric current to aggregate fine metal particles, enhancing their recovery [113,114]. These electrochemical processes offer high-purity metal recovery while generating minimal chemical waste, making them attractive for sustainable E-waste recycling. However, they require significant electricity input and are generally slower than pyrometallurgical methods. Their effectiveness is maximized when integrated with hydrometallurgical techniques, improving overall recovery efficiency.

5.6. Advantages/Disadvantages and Efficiency of Mineral Recovery Processes from E-Waste

A summary of the advantages and disadvantages of each mineral recovery technology from E-waste, described above, is shown in

Table 5. Summary of the advantages and disadvantages of each mineral recovery technology from E-waste.

Technology	Advantages	Disadvantages
❖ Physical & Mechanical Separation	Low cost and energy-efficient; No use of hazardous chemicals; Effective for pre-processing	Ineffective for fine or mixed metal recovery; Cannot separate metals from complex compounds
❖ Hydrometallurgical Processes	High selectivity and metal recovery efficiency; Lower energy consumption compared to pyrometallurgy; Can recover multiple metals (gold, silver, copper, etc.)	Requires hazardous chemicals (e.g., cyanide, acids); Generates wastewater that requires treatment; Slow processing
❖ Pyrometallurgical Processes	High recovery efficiency for various metals; Fast processing time; Can handle mixed metal compositions	High energy consumption; Air pollution from gas emissions; Requires pre-treatment to remove plastics and hazardous materials
❖ Bio-metallurgy	Environmentally friendly; Low energy consumption; Can recover metals from low-grade E-waste	Slow processing rate; Requires specific conditions for microbial activity; Limited scalability for industrial applications
❖ Electrochemical Processes	High-purity metal recovery; Low chemical waste; Can be integrated with hydrometallurgical processes	Requires significant electricity input; Slower compared to pyrometallurgy; Ineffective for complex metal mixtures

.

Moreover, a detailed comparison of the five technologies for mineral recovery from E-waste, focusing on their effectiveness in recovering specific materials is shown in

Table 6. Technology Comparison for Specific Materials.

Technology	Gold (Au)	Silver (Ag)	Copper (Cu)	Rare Earth Elements (REEs)	Platinum Group Metals (PGMs)	Ferrous Metals (Fe, Ni, Co)	Aluminum (Al)
❖ Physical & Mechanical Separation	Not effective	Not effective	Good efficiency (electrostatic, density separation)	Not effective	Not effective	Good efficiency (magnetic separation)	Good efficiency (eddy current separation)
❖ Hydrometallurgical Processes	Very effective (cyanide leaching)	Very effective (acid leaching)	High efficiency (acid leaching, solvent extraction)	Limited effectiveness	High efficiency (chloride leaching)	Limited effectiveness	Inefficient
❖ Pyrometallurgical Processes	High efficiency (smelting, refining)	High efficiency (smelting)	High efficiency (smelting, roasting)	Not commonly used	Effective (high-temperature refining)	Effective for ferrous metals	Effective (high-temperature recovery)
❖ Bio-metallurgy	Possible (bioleaching)	Possible (bioleaching)	Good efficiency (bioleaching with bacteria)	Promising research (microbial bioleaching)	Limited research	Not effective	Inefficient
❖ Electrochemical Processes	High purity recovery (electrowinning)	High purity recovery (electrowinning)	Effective (electrowinning, electrorefining)	Not effective	Effective (electrorefining for platinum)	Inefficient	Inefficient

. Different metals require different recovery methods, each with varying levels of efficiency and effectiveness, as discussed below.

• Gold (Au) and Silver (Ag): They are among the most valuable metals found in E-waste. They are best recovered through hydrometallurgical and pyrometallurgical methods, both of which are highly effective in extracting these precious metals. Additionally, electrochemical processes can also be used to recover Au and Ag with high purity, ensuring that these valuable materials are efficiently separated and refined.
• Copper (Cu): It is commonly found in E-waste, particularly in circuit boards and wiring. It can be efficiently extracted using hydrometallurgy, pyrometallurgy, and electrochemical methods. These processes ensure high recovery rates of Cu, which is a key material in electronics due to its excellent conductivity and recyclability.
• Rare Earth Elements (REEs): The recovery of REEs, such as neodymium and dysprosium, is a more challenging task, as traditional recovery methods often struggle to extract these elements efficiently. While bio-metallurgy (using microorganisms to extract metals) shows promise for REE recovery, it requires further research and optimization to enhance its effectiveness and scalability [115].
• Platinum Group Metals (PGMs): PGMs, including platinum, palladium, and rhodium, are highly valuable but are typically found in smaller quantities in E-waste. The most effective recovery methods for PGMs are hydrometallurgy and pyrometallurgy, which allow for the extraction of these metals with high efficiency.
• Ferrous Metals (Fe, Ni, Co): They are best recovered using physical separation methods, such as magnetic separation, or through pyrometallurgical techniques. These methods effectively separate ferrous metals from other materials, ensuring that they can be recycled and reused.
• Aluminum (Al): It is widely used in electronics, particularly in housings and casings. The most efficient recovery methods for aluminum include physical separation techniques, such as eddy current separation, or through pyrometallurgy. These methods are effective in extracting aluminum with minimal loss and ensuring that it can be reused in new products.

In summary, different recovery methods are suited to different types of metals, with hydrometallurgical and pyrometallurgical processes being highly effective for many precious and valuable metals, while physical separation methods are particularly useful for ferrous metals and aluminum. The recovery of REEs still presents a challenge but offers significant potential for innovation with continued research into bio-metallurgy and other emerging techniques.

5.7. Challenges and Barriers of Mineral Recovery Processes from E-Waste

The challenges categorized into: (1) technical; (2) environmental; (3) occupational health and safety; (4) energy and climate impact; (5) waste management; and (6) efficiency and scalability are:

• Technical challenges related to complexity of material composition and the requirements of advanced recovery methods are: (a) The heterogeneous composition of E-waste and the miniaturization of components make the recovery of critical and precious minerals highly complex. Devices often contain multilayered structures, composite materials, and intricate alloys that are difficult to dismantle and separate efficiently; and (b) Techniques like hydrometallurgy, pyrometallurgy, and bioleaching are needed to extract valuable metals, each with their own technological limitations and process complexities.
• Environmental challenges concerning toxicity byproducts and chemical pollution, air pollution from high-temperature processes, and secondary waste stream management are (a) Hydrometallurgical processes use acids and cyanide-based solutions, generating hazardous liquid waste that risks soil and water contamination if mismanaged; (b) Pyrometallurgical techniques release toxic gases such as dioxins, sulfur dioxide, and heavy metal vapors, contributing to air pollution and long-term ecological damage, and (c) Processes generate residuals like slags, sludges, and spent acids that require careful disposal or treatment. Poor management can lead to heavy metal leaching into ecosystems.
• Occupational health and safety challenges involving exposure to hazardous substances, and health risks are: (a) Workers handling E-waste are at risk from toxic elements such as lead, mercury, arsenic, and brominated flame retardants, and (b) Improper handling can result in respiratory diseases, neurological disorders, and cancer. Ensuring adequate protection and proper handling protocols is critical for worker safety.
• Energy and climate impact in view of high energy consumption, and trade-offs of low-energy alternatives are: (a) Pyrometallurgical processes are energy-intensive, significantly contributing to GHG emissions and climate change, and (b) While bioleaching and electrochemical recovery are more energy-efficient, they are often slower and less effective in extracting metals, limiting industrial viability.
• Waste Management challenges relating to residual waste disposal, and lack of sustainable strategies are: (a) The byproducts of mineral recovery often require further treatment to prevent environmental contamination, and (b) Many current waste treatment methods are insufficiently sustainable, increasing the ecological burden of recycling operations.
• Efficiency and scalability challenges concerning low selectivity and purity, reliance on primary mining, scalability of emerging technologies, and balancing recovery and sustainability are: (a) Existing recovery methods often yield low-purity metals and suffer from inefficient selective separation, requiring additional refining, (b) Inefficiencies in recycling contribute to continued dependence on virgin resource extraction, (c) Biological techniques like bioleaching face hurdles such as slow reaction times, inconsistent yields, and limited scalability, posing challenges for industrial-scale adoption, and (d) Achieving high recovery rates while minimizing environmental harm and maintaining cost-effectiveness remains a persistent research and development hurdle.

Despite the potential of scaling technologies such as additive manufacturing (i.e., 3D printing) to minimize waste and enhance sustainability, significant challenges remain in their widespread adoption within a CE framework [115,116,117]. A key barrier to the full deployment of these technologies in waste management is the integration of Industry 4.0 solutions with CE principles [118,119]. To successfully transition to a CE in E-waste recycling, several key steps must be implemented:

• Design for recycling: Electronic products should be developed with recyclability in mind, incorporating modular components, standardized materials, and minimal hazardous substances to facilitate efficient disassembly and recovery [3,12,13];
• Advanced material separation technologies: Implementing innovative separation techniques such as hydrometallurgical and bioleaching processes can enhance the recovery of valuable metals and rare earth elements from E-waste. Additionally, the use of AI-powered robotic sorting systems can improve material classification and reduce contamination.
• Robust collection and reverse logistics networks: Establishing efficient take-back schemes and drop-off points for consumers, combined with digital tracking systems, can ensure higher recovery rates and minimize improper disposal.
• Economic incentives and policy measures: Governments and industry stakeholders should introduce financial incentives such as tax breaks, subsidies, and extended producer responsibility (EPR) programs to encourage manufacturers to design recyclable products and invest in CE initiatives.
• Industry collaboration and standardization: Strengthening partnerships among manufacturers, policymakers, and recyclers is crucial for developing unified standards for material recovery, ensuring consistency, and fostering innovation in recycling technologies.

By integrating these strategies, scalable and sustainable E-waste management systems can be developed. A closed-loop approach that continuously recovers and reuses materials will not only reduce dependence on virgin resources but also enhance both economic and environmental sustainability, driving the transition toward a CE.

6. Economics

The economic feasibility of E-waste recycling is shaped by multiple cost factors, including high capital investment, operational expenses, and uncertain market returns. Despite the potential value of recovered metals, E-waste recycling faces financial hurdles that hinder its large-scale adoption. Key factors influencing the economic viability of these processes include fluctuating metal prices, expensive recovery technologies, collection and transportation costs, labor expenses, and regulatory compliance requirements.

6.1. Investment Costs and Capital Expenditures

Setting up an E-waste recycling facility requires significant upfront investment in infrastructure, specialized equipment, and processing technologies. Automation and emerging technologies such as robotic disassembly, artificial intelligence (AI)-based sorting, and blockchain-enabled traceability offer long-term efficiency benefits but come with high initial investment costs. While these innovations improve material recovery rates and reduce manual labor dependency, the high cost of implementation makes them less accessible to smaller recycling enterprises, particularly in developing regions where investment capital is limited [120,121,122,123]. Advanced recovery methods, such as hydrometallurgy, pyrometallurgy, and bioleaching, necessitate sophisticated processing units, chemical treatment facilities, and emissions control systems, all of which contribute to high capital expenditures (CAPEX). Moreover, the cost of acquiring or retrofitting industrial spaces, ensuring proper waste handling measures, and obtaining necessary permits further increases the financial burden on recyclers. The estimated total initial investment ranges from $50,000 to $500,000, depending on scale and location [123].

For E-waste recycling to become a viable and profitable industry, it is crucial to address cost inefficiencies and create financially sustainable business models. This requires a combination of technological advancements, policy interventions, and market-based incentives to reduce capital and operational costs while maximizing material recovery efficiency. Investments in automation, digitalization, and decentralized recycling hubs can help lower logistics costs, improve recovery rates, and enhance profitability. Policymakers must also focus on leveling the economic playing field by integrating CE principles into regulatory frameworks, ensuring that recycled materials become a competitive alternative to newly mined resources. By implementing eco-design requirements, mandatory take-back schemes, and stricter enforcement of E-waste regulations, governments can help accelerate the transition toward a more financially sustainable and environmentally responsible E-waste management system.

The prospects for mineral recovery from E-waste are largely favorable, with increasing feasibility anticipated. This positive outlook is driven by several factors [123]. Firstly, the global volume of urban waste, including e-waste, is projected to rise considerably, with total urban waste reaching an estimated 3.4 billion tonnes by 2050 [4,74]. E-waste contains the highest or most valuable mineral resources among urban waste types, with a current estimated monetary value of approximately $57 billion in raw materials, though only about $10 billion worth is sustainably recycled today [74]. Secondly, the demand for CRMs, which are vital for advanced technologies, is continuously increasing [74]. This escalating demand makes recycling metals from secondary sources like E-waste a priority due to the finite nature of primary sources. Moreover, rising mineral prices are expected to make recovery from waste stockpiles more economically viable. As countries advance technologically, the environmental protection costs associated with mineral production are projected to decrease, making environmentally sound E-waste recovery more economically appealing over time. New legislation aiming to increase environmental contributions will also positively impact feasibility. However, it’s worth noting that current mineral recycling rates and feasibility from E-waste remain relatively low due to the complexity of products and processing challenges.

Moreover, developed countries generally possess better access to technology and financial resources, facilitating more efficient E-waste recovery. To enhance feasibility in developing countries, several mechanisms are crucial [123]:

(a)

Developed countries bear a responsibility to share knowledge, transfer state-of-the-art technology, and invest in facilities within developing countries to address environmental issues, particularly those stemming from E-waste exports;

(b)

Many developing countries currently lack sufficient or effectively implemented E-waste legislation. There is a pronounced need for country-specific standards, comprehensive legislation, public awareness campaigns, and robust implementation. Special incentives through legislation are vital to overcome existing barriers to larger-scale mineral recovery. Tailored action plans for each country are also necessary for environmental sustainability. Formalizing the informal recycling sector, for example through EPR schemes and adequate funding, can significantly improve the benefits and feasibility of E-waste recycling;

(c)

Developing countries may not prioritize funding for E-waste research and development (R&D) or legislation, often due to a perceived low economic contribution. Establishing special funds can help reduce environmental protection costs and incentivize the creation of economic and financial business models for recycling facilities in regions with insufficient capacity, such as Africa and Asia. International agreements should also establish fair and special policies for countries with low development levels to increase their sustainable contribution to mineral recovery.

(d)

Developing countries must build statistical databases on waste and standardize waste definitions to enhance management practices. Increased public awareness and strong R&D support from policymakers can accelerate the growth of E-waste recovery, encouraging households to generate income from e-waste. While Europe is currently the leading E-waste collector (42.3% of total e-waste), regions like Asia and Africa have significantly lower collection rates, highlighting the global disparity in E-waste management capacities.

6.2. Operational Costs and Ongoing Expenses

In addition to initial investments, E-waste recycling operations involve continuous expenses that affect profitability. Collection and transportation costs are major cost drivers, as E-waste must be gathered from various locations, often requiring specialized handling due to hazardous components such as batteries, heavy metals, and flame retardants. The logistics of collecting and safely transporting discarded electronics to processing centers can be costly, particularly in regions with poor waste collection infrastructure or fragmented supply chains.

Energy consumption is another significant operational cost, particularly for energy-intensive processes such as pyrometallurgical smelting and electrochemical metal recovery. High electricity and fuel costs can erode profit margins, making certain recycling methods financially unviable unless supplemented with renewable energy sources or government subsidies. Additionally, the cost of chemicals, reagents, and wastewater treatment in hydrometallurgical and bioleaching processes further adds to the total cost of operations (OPEX). The estimated OPEX ranges from $144,000 to $696,000 annually, depending on the scale of operations [123].

Labor expenses, particularly in countries with strict environmental and safety regulations, also contribute to high operating costs. Skilled workers are required for manual disassembly, sorting, and hazardous waste handling, making labor-intensive recycling methods more expensive. Typically, labor expenses account for 30% to 50% of total OPEX [123]. In contrast, informal sector recyclers, often operating in unregulated markets, may offer lower-cost alternatives but at the expense of worker safety, environmental protection, and material recovery efficiency. The utilities and facility management can represent 20% to 30% of OPEX, especially in energy-intensive operations [123]. These costs can be optimized by considering the following approaches [123]: (a) Energy efficiency: Invest in energy-efficient equipment and practices to reduce utility expenses; (b) Route optimization: Implement efficient logistics planning to minimize transportation costs; (c) Preventive maintenance: Regular equipment maintenance can prevent costly repairs and downtime; (d) Staff training: Well-trained staff can improve operational efficiency and reduce errors; and (e) Partnerships: Collaborate with local organizations for shared resources and community engagement.

A financial model tailored for setting up and operating an E-waste recycling facility in the United Arab Emirates (UAE),as an example, is given in Appendix A. This model includes CAPEX, OPEX, and revenue projections. It’s built for a small to medium-scale facility with capacity to process about 5000–10,000 tons of E-waste annually. The CAPEX and OPEX are estimated at USD 1,327,000 and USD 613,000 per year, respectively. The total revenue is estimated at USD 1,525,000 per year. The net profit (year 1) is estimated at USD 912,000 and payback period is about 2 years. These costs can be reduced considering the following approaches: (a) Use of solar panels or renewable energy integration to reduce OPEX and carbon footprint; (b) Use of AI sorting systems to improve recovery efficiency and metal purity; (c) Partnership with manufacturers to guarantee inflow of waste and additional revenue from corporate social responsibility (CSR); and (d) Government incentives that may reduce initial capital requirements.

Government incentives play a pivotal role in enhancing the economic feasibility of E-waste recycling, particularly in regions where the high costs of collection, processing infrastructure, labor, and energy consumption pose significant barriers to entry. To promote widespread adoption of E-waste recycling technologies—especially those used for critical and precious mineral recovery—public policy tools must address both supply- and demand-side challenges. One effective strategy could involve subsidizing electricity costs for certified E-waste recycling facilities, especially those operating energy-intensive processes such as smelting, hydrometallurgy, or electrochemical extraction. Similar models have been implemented in energy-intensive manufacturing sectors (e.g., steel and aluminum), where tiered electricity pricing or exemptions from certain energy levies are provided to reduce operational costs while maintaining environmental compliance. Governments can apply a similar approach to incentivize low-carbon E-waste recycling technologies, provided environmental standards are upheld.

Additional policy incentives may include: (a) Capital investment grants or low-interest green loans to support the development or upgrading of recycling infrastructure; (b) Tax credits or deductions for manufacturers and recyclers that meet specific E-waste recovery targets or use recycled critical materials in production; (c) EPR compliance subsidies, especially for small and medium-sized enterprises that may lack the resources to manage product take-back systems independently; (d) Performance-based rewards, such as per-ton incentives for E-waste collected and processed through certified channels; and (d) Public procurement preferences, in which governments prioritize suppliers who use recycled materials, thereby stimulating market demand for secondary raw materials from E-waste. In addition, governments can play a critical role in facilitating technology transfer and skills training to reduce costs and improve recovery efficiencies. This is particularly relevant in developing economies, where investment in modern technologies and human capital remains limited.

In summary, a multi-layered incentive structure—combining financial, regulatory, and market-based instruments—can significantly reduce the economic burden on recyclers and help scale E-waste recycling systems. These measures not only contribute to a CE but also support national goals related to environmental protection, resource security, and innovation in green technology sectors.

6.3. Market Volatility and Financial Returns

The profitability of E-waste recycling is highly dependent on fluctuating market prices for recovered metals such as gold, silver, copper, palladium, lithium, and REEs. Metal prices are influenced by global supply-demand dynamics, geopolitical factors, and macroeconomic conditions. When prices for primary raw materials are low, recycled metals become less competitive, making E-waste recycling financially unsustainable without government support or incentive programs. Additionally, the composition of E-waste is constantly evolving, with manufacturers using smaller amounts of valuable metals in newer devices while incorporating more composite materials and plastics that are harder to recycle. This trend reduces the economic yield per unit of processed E-waste, making it more difficult to achieve high recovery rates and profitability. Despite these challenges, financial incentives such as EPR schemes, tax breaks, recycling subsidies, and material recovery credits can help bridge the cost gap and improve the economic outlook for E-waste recycling businesses. Governments and policymakers play a crucial role in leveling the playing field by introducing regulations that internalize the environmental costs of primary mining and promote the use of secondary raw materials from recycled E-waste.

6.4. Comparative Cost Advantage of Primary Mining vs. Recycling

The cost of primary mining for critical minerals varies significantly depending on several factors, including the type of mineral, geographic location, mine scale, ore grade, and infrastructure availability [120,121]. Appendix B outlines a detailed summary of capital expenditures (CAPEX) and operating expenditures (OPEX) across various mining projects. According to the International Energy Agency (IEA) [124], meeting climate-aligned development scenarios will demand substantial mining investments. For instance: (a) Under the Announced Pledges Scenario (APS), approximately $590 billion in new capital investments is required between now and 2040, and (b) Under the more ambitious Net Zero Emissions by 2050 Scenario (NZE), capital requirements rise by around 30%, reaching nearly $800 billion by 2040. Among all critical minerals, copper represents the largest share of future investment, with required capital reaching $330 billion under APS and $490 billion under NZE. These growing figures reflect not only rising demand but also increasing costs per tonne of ore, largely due to declining ore quality and more complex extraction environments. To contextualize these facts,

Table 7. A comparative analysis of critical mineral extraction via primary mining versus E-waste recycling.

Aspect	Primary Mining	E-Waste Recycling
Capital Expenditure (CAPEX)	Very high cost; typically, $500 million–$10+ billion USD	Moderate cost; Typically, $2 million–$10 million USD for medium-scale facilities
Operating Expenditure (OPEX)	Moderate to high cost; Ranged from $20,000 to $50,000 USD/tonne of refined critical metal	Lower cost; It ranges from $10,000 to $25,000 USD/tonne, depending on technology and material type.
Ore/Material Grade	Often low-grade ore (0.5–3%), requiring processing of huge volumes	E-waste has high metal content (up to 40% by weight), e.g., gold in PCBs can be 100× richer than gold ore
Energy Consumption	High energy consumption; Large-scale excavation, crushing, smelting	Lowe energy consumption; Mostly mechanical, chemical, and electrochemical processes
GHG Emissions	High GHG emissions from mining operations, heavy fuel usage, and smelting	Low GHG emissions; Potential for near-zero emissions if powered by renewables
Environmental Impact	Significant impact in relation to land degradation, mine tailings waste, and water contamination	Low impact; Fewer emissions and no landscape disruption, but still requires hazardous waste management
Extraction Efficiency	Moderate efficiency depending on ore quality and technology (often < 90%)	High extraction efficiency; Precious metals like Au, Pd, and Cu can be recovered with >90% efficiency with advanced methods
Resource Scalability	Limited by geology, geography, and permitting	Treatment technologies are scalable in urban areas; urban mining becomes more viable with growing E-waste volumes
Time to Set Up Operations	Long time for mineral extraction; Often 5–10 years due to exploration, feasibility studies, permits	Short operation time; Typically, 1–2 years for plant construction and operation setup
Economic Viability	Highly dependent on metal prices and mine life	Economically attractive at small scale, especially where recycling fees and metal recovery both generate value
Strategic Benefit	Supports supply independence, but geopolitically sensitive	Enhances circular economy, reduces import dependency, and supports critical mineral security

provides a comparative analysis of critical mineral extraction via primary mining versus E-waste recycling, examining key dimensions such as cost, extraction efficiency, scalability, and environmental impact.

In summary, primary mining involves high upfront capital and operating costs, significant environmental degradation, and long lead times due to permitting and infrastructure development. The efficiency of metal extraction is often limited by low ore grades and declining resource quality. In contrast, E-waste recycling presents a cost-effective, energy-efficient, and environmentally sustainable alternative. With faster setup times, higher metal concentrations, and urban scalability, it offers compelling advantages—especially in resource-constrained or highly urbanized regions.

A specific case in point is gold extraction, which clearly illustrates the economic potential of E-waste recycling. Traditional gold ore contains only 5–10 g per tonne, leading to extraction costs of approximately $30,000–$50,000 USD per kilogram. In comparison, printed circuit boards (PCBs) found in E-waste may contain 1000–3000 g of gold per tonne, enabling more cost-effective recovery—estimated at just $10,000–$20,000 USD per kilogram using advanced recycling technologies. This stark contrast underscores the growing viability and economic promise of urban mining for high-value metals. However, this cost advantage is not universal. The economic feasibility of E-waste recycling depends on several contextual factors, including access to technology, collection efficiency, regulatory support, skilled labor, and financing. In many developing and underdeveloped countries, the lack of formal recycling infrastructure, insufficient E-waste volumes, and limited access to capital or advanced technology can hinder the viability of such operations [121,123]. Additionally, transportation and logistical barriers in fragmented or rural areas may further erode the cost benefits.

When considering initial investment costs, especially for state-of-the-art recovery systems, mineral recovery from E-waste may not always be more economical than traditional mining—particularly in regions with established mining operations or low labor costs. Therefore, while E-waste recycling holds significant promise, it is not yet a universal substitute for primary mining [121].

Nevertheless, global trends point to an increasing shift toward E-waste investment, particularly in countries with supportive policies, urban density, and a focus on sustainability. Furthermore, advances in recycling technologies—some of which originated from efforts to process mining waste—have contributed to innovations in E-waste recovery. This cross-sectoral synergy highlights how the development of tailings and mine-waste recycling indirectly supports the broader evolution of urban mining technologies [121].

In conclusion, while E-waste recycling may not yet fully replace traditional mining, it contributes meaningfully to resource security and supports the circular economy by reducing dependence on virgin raw materials. Future progress will rely on addressing infrastructural and financial barriers, enabling global access to clean recycling technologies, and integrating lessons learned from both mining and waste management sectors.

6.5. Balancing Costs and Sustainable Growth

As discussed, the recovery of minerals from E-waste currently faces significant cost challenges, stemming largely from inefficiencies within existing systems [121]. A primary issue is the collection and sorting of e-waste, with approximately 83% of E-waste generated globally remaining undocumented [4,74], often leading to environmentally harmful and economically inefficient disposal methods like open burning or illegal dumping. This substantial loss of material means a missed opportunity for resource recovery. From the perspective of environmental protection, specific environmental protection costs are a factor in E-waste recovery [121]. While developed countries may incur higher total environmental protection costs due to stringent regulations, the per-ton cost of mineral production can decrease with technological advancements. In less developed countries, where technological access is limited, these environmental protection costs can be a significant barrier. Current technologies often struggle with the inherent inhomogeneity of e-waste, the low concentrations of valuable materials, and product designs that hinder easy component separation, making the recycling process expensive and impacting its overall feasibility [121]. Notably, Yıldız [121] highlighted that waste recovery from mining operations is more feasible than from E-waste today, though the feasibility of E-waste recovery is improving, particularly in developed nations. To overcome these cost barriers, special incentives through legislation are deemed vital.

Despite current challenges, the outlook for mineral recovery from E-waste is largely favorable and expected to increase in feasibility, contributing significantly to sustainable growth [121]. This is driven by several factors: (a) the increasing volume of e-waste, which is projected to grow substantially globally; (b) the fact that E-waste contains the highest or most valuable mineral resources among urban waste types, with an estimated monetary value of approximately $57 billion in raw materials annually; and (c) the continuously increasing demand for CRMs essential for high technology. The rising prices of minerals are also expected to enhance the economic viability of recovery from waste stockpiles.

For sustainable growth, a holistic approach is crucial. A study by Yıldız [121] indicates that as countries’ development levels increase, their capacity to use special environmental protection and recovery technologies, and their capacity to use artificial intelligence or advanced/new technology, also rise. This technological access enables greater energy savings and a higher capacity to reduce carbon emissions in E-waste recovery activities. Furthermore, higher development levels are correlated with a more efficient use of resources and improved waste recovery efficiency. These factors contribute directly to environmental sustainability and economic efficiency. While the economic contribution to the state from E-waste recovery may be lower in less developed countries, leading to less R&D funding and legislation, increasing public awareness and policymaker support for R&D can accelerate growth and encourage households to generate income from e-waste. Developed nations, with their superior access to finance and technology, have a responsibility to share knowledge, transfer state-of-the-art technology, and invest in facilities in developing countries to address environmental issues related to e-waste. Implementing country-specific standards, legislation, and public awareness campaigns are crucial for effective E-waste management and achieving a circular economy. Formalizing the informal recycling sector and establishing special funds can also significantly improve the economic and environmental benefits of E-waste recycling, especially in regions like Africa and Asia where capacities are insufficient.

7. Regulatory and Policy

The lack of uniform E-waste regulations across different regions significantly impedes global recycling efforts. While some countries have well-established Extended Producer Responsibility (EPR) programs—mandating structured networks for E-waste collection, management, and monitoring—others lack enforcement mechanisms, leading to the persistence of informal recycling practices, illegal exports, and environmental degradation [125].

Globally, over 50 million tonnes of E-waste are generated each year, but only 17.4% is formally collected and recycled [4,74]. Regions with legally binding EPR policies, such as the EU, report higher collection rates—over 45% on average—compared to less than 10% in countries without formal legislation. This disparity highlights the critical role that regulatory frameworks play in shaping sustainable E-waste outcomes.

In Europe, all countries have legislation or policies governing E-waste [4]. Member states are required to extend the lifecycle of E-waste, implement separate collection systems, and meet specific recycling and treatment targets while combating illegal waste exports. The EU directive on E-waste [14] is founded on two key principles: EPR and the polluter pays principle (PPP). Under this directive, producers are accountable for the take-back and recycling of their products. However, inconsistencies in definitions have led to varied implementations across member states. Some enforce stringent controls on E-waste trafficking, while others adopt more flexible monitoring strategies. Despite the directive’s goal of harmonizing E-waste management across Europe, these disparities create challenges for multinational manufacturers, who must navigate country-specific regulations rather than adhering to a unified framework [126]. For example, Germany and the Netherlands apply rigorous controls and traceability mechanisms for E-waste trafficking, while other states adopt more flexible or fragmented oversight.

In North America, neither the United States nor Canada has federal level E-waste regulations. Instead, E-waste management is governed at the state or provincial level. In the U.S., 25 states have enacted specific E-waste legislation, each with distinct requirements and covered products, leading to inconsistencies that complicate compliance for manufacturers operating across multiple jurisdictions [127]. Similarly, Canada relies on provincial stewardship programs, with private sector actors overseeing collection and processing, but enforcement remains uneven [128].

In Asia, out of the 46 countries in the region, 29 lack national E-waste legislation [4]. China, the world’s largest E-waste producer, also remains a major recipient of illegally imported E-waste, with an estimated 8 million tons entering the country annually [129,130]. India, on the other hand, has had E-waste-specific legislation since 2011, incorporating EPR principles [129]. The E-waste Management Rules [131,132] impose responsibilities on traders, producers, online retailers, and Producer Responsibility Organizations (PROs). In major Indian cities, E-waste recycling is an emerging and rapidly growing market [133]. However, enforcement gaps persist, especially in rural areas where informal recycling dominates the sector, often leading to hazardous practices.

A key issue across many developing nations is the limited capacity to enforce existing regulations. Although many laws formally prohibit the import of hazardous waste or mandate proper recycling procedures, weak oversight allows loopholes to persist. For instance, E-waste is frequently shipped under the label of “second-hand electronics” or “repairable goods” to circumvent import bans, violating both national laws and international agreements such as the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal.

Despite efforts from organizations like the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal, and similar international frameworks, the absence of universal definitions, inconsistent national targets, and poor coordination undermine global progress. Moreover, technology transfer barriers—including high costs, intellectual property restrictions, and a lack of financial incentives—prevent many low-income countries from accessing or implementing state-of-the-art recycling technologies. Consequently, informal recycling remains dominant, often in unsafe and environmentally damaging conditions.

An often-overlooked aspect is the role of the informal sector, especially in Asia and Africa, where it accounts for a significant portion of E-waste collection and preliminary material recovery. Although typically operating outside formal regulations, these informal networks are highly efficient in collecting and dismantling E-waste. Emerging models in India, South Africa, and Ghana are exploring how informal workers can be integrated into formal systems through training, certification, and cooperative partnerships. This approach not only improves environmental compliance but also safeguards livelihoods and enhances data traceability.

Furthermore, a data gap persists across most regions. Official statistics often underrepresent the actual volume of E-waste processed, especially by informal actors. Additionally, inconsistent reporting standards and varying national definitions of E-waste hinder cross-border comparisons and complicate policymaking. There is a clear need for harmonized data collection, standardized definitions, and global reporting frameworks to improve transparency and accountability.

Several countries have demonstrated effective models. For instance: (a) Japan’s Home Appliance Recycling Law mandates recycling quotas for producers and has led to material recovery rates of over 80% for large appliances; and (b) South Korea has established a national EPR Clearinghouse to streamline compliance and reporting across industries, coupled with public-private partnerships to improve awareness and infrastructure.

To improve global alignment and promote sustainable E-waste recycling, several policy recommendations emerge: (a) Update and strengthen international agreements, such as revising the Basel Convention to include stricter penalties for non-compliance and a standardized classification of E-waste; (b) Expand EPR schemes globally, ensuring that producers are accountable regardless of the country of sale; (c) Develop a globally recognized E-waste recycling certification standard, enabling transparent and verifiable compliance with safety and environmental benchmarks; and (d) Support technology transfer and capacity building, especially in low- and middle-income countries, through funding mechanisms, open-source technology platforms, and international collaboration.

In conclusion, while the regulatory landscape for E-waste is evolving, it remains fragmented. A more coherent, enforceable, and inclusive global policy framework—supported by accurate data and equitable access to technology—is essential to scale up responsible E-waste recycling and mineral recovery practices.

8. Stakeholder Engagement

Low consumer awareness and limited access to proper recycling channels contribute to poor E-waste recovery rates. Many consumers are unaware of take-back programs or lack incentives to participate. Education campaigns, financial incentives, and convenient collection systems are essential to encourage responsible disposal and improve material recovery [134,135,136,137,138,139,140,141,142,143,144,145,146].

For example, in a study by Dhir et al. [138], adopting an extended Valence Theory (VT) framework, found several key factors influencing Japanese consumers’ intentions to recycle E-waste. Firstly, perceived benefit demonstrated a positive association with recycling intentions, suggesting that consumers are more inclined to recycle when they recognize the advantages. Similarly, value compatibility and environmental concerns positively influenced the intention to recycle, indicating that alignment with personal values and awareness of environmental degradation are important motivators. Conversely, perceived risk and openness to change did not show significant associations with recycling intentions in this study. The extended VT model, incorporating these factors, explained 42% of the variance in recycling intentions. Furthermore, the study identified that contacting retailers/recycling centres and local government offices positively moderated the influence of value compatibility and environmental concerns/perceived benefit on recycling intentions. However, selling E-waste to the grey market negatively moderated the relationship between value compatibility and recycling intention. Notably, demographic variables did not significantly influence the intention to recycle e-waste. Despite these findings, the study presents several gaps. Firstly, it did not differentiate between various types of e-waste, which could have differing recycling behaviors associated with them. Secondly, the model only included specific values, and future research could incorporate other values such as altruistic and biospheric ones, potentially in combination with the Value-Belief-Norm (VBN) theory. The study also did not account for the impact of economic incentives like buy-back schemes. Methodologically, the cross-sectional online survey using self-reported data may introduce bias, and future longitudinal studies are suggested. The research focused solely on individual consumers, neglecting the E-waste generated by organizations. Finally, the generalizability of the findings is limited to developed countries with similar cultural values to Japan, suggesting a need for cross-country comparisons.

In a study by Almulhim [141], which was conducted in Dammam city, Saudi Arabia, it was revealed that while a significant portion of household respondents (65.0%) claimed awareness of E-waste, a larger percentage (69.8%) reported not having been adequately educated on its serious environmental implications. Consequently, common disposal practices involved storing E-waste at home (45%) or discarding it with regular household waste (32%). The study also identified the most common electronic devices in households as mobile phones (96%), TVs (79%), and laptops (71%). Despite the limited education, a notable majority (88.35%) expressed willingness to participate in E-waste management after gaining a proper understanding, and 91.2% supported the implementation of Extended Producer Responsibility (EPR) programs. However, statistical analysis indicated no remarkable changes in household awareness or willingness based on sociodemographic attributes such as gender, marital status, education level, or age. Despite these valuable insights, the study [141] acknowledges several gaps. Firstly, there was an absence of precise data on E-waste production, imports, sorting, reuse, and disposal in Saudi Arabia, which hinders the development of more accurate models and substantial conclusions. Secondly, the small sample size and its focus solely on Dammam city limit the generalizability of the findings to the entire nation. Furthermore, the research concentrated on households, neglecting the perspectives of other key stakeholders in the E-waste management chain. The study also notes a lack of longitudinal analysis to track changes in attitudes and behaviors over time. Finally, the authors highlight a discrepancy between behavioral research and the understanding of the technological and financial aspects of electronic product lifecycles and the circular economy within the Saudi Arabian context.

In another study by AbdulWaheed et al. [143], it was highlighted that attitudes, subjective norms, and perceived behavioral control significantly and positively influence E-waste recycling intentions among United Arab Emirates’ (UAE) residents. Furthermore, the study confirms that environmental consciousness strengthens the positive effect of attitudes on these recycling intentions. In terms of actual behavior, the research demonstrates that E-waste recycling intention positively impacts E-waste recycling behavior, and this relationship is further strengthened by the perceived infrastructure support available for recycling. Although the cost of recycling was found to negatively affect recycling behavior, its moderating effect on the intention-behavior link was not statistically significant. Overall, the study supports the applicability of the Theory of Planned Behavior in the context of E-waste recycling in the UAE and highlights the important roles of environmental consciousness and infrastructure support. Despite these insightful findings, the study acknowledges several limitations. Firstly, the research was conducted specifically within the UAE, where high levels of E-device consumption are prevalent, potentially influencing the general awareness of E-waste issues. Therefore, the generalizability of these findings to other contexts might require careful consideration. Secondly, the R-squared values for both recycling intention and behavior suggest that a considerable portion of the variance remains unexplained, indicating the influence of factors not included in the proposed model. Consequently, future research could explore other potential determinants of E-waste recycling intention and behavior, such as the psychological ownership of the environment and the practice of frugal consumption, to provide a more comprehensive understanding of this complex issue

Finally, the scoping review [146] reveals that current research on consumer behavior in handling Waste of Electrical and Electronic Equipment (WEEE) predominantly focuses on recycling and linear economy concepts like disposal and storage. Among the 9R framework (Refuse, Rethink, Reduce, Reuse, Repair, Refurbish, Remanufacture, Repurpose, Recycle), recycle is the most extensively studied strategy, while repair and reuse receive considerably less attention. The study also highlights a geographical bias, with a significant number of investigations conducted in China and India, while regions like Europe and North America are scarcely examined. Furthermore, the research identifies a “Circular Value Chain Blind Spot”, indicating that recommendations for stakeholders in the electronics industry primarily target governments and businesses, despite consumers being recognized as crucial actors in the circular economy. The study [146] identifies several key research gaps. There is a notable underrepresentation of consumer-centric research across the broader spectrum of the 9R framework beyond recycling, including strategies related to smarter product use and extended product lifespan. Moreover, the lack of concrete consumer action strategies in the literature, with a primary emphasis on recommendations for governments and companies, represents a significant gap. The review also suggests a need for more differentiated research that considers the varying behaviors associated with different types of WEEE and the influence of cultural factors on consumer handling of electronic waste. Finally, the study points out the conceptual limitations of applying all 9R strategies directly to consumers in the WEEE sector.

9. Synergistic Leverage for Sustainable E-Waste Management

The below discussion addresses the central research question: “How can technological advancements, policy interventions, and stakeholder engagement be synergistically leveraged to bridge the existing gaps in E-waste management, thereby optimizing the recovery of critical and precious minerals and fostering a resilient CE for electronics?” The analysis of the proposed strategy for sustainable E-waste recycling reveals that a cohesive and interconnected approach across these three domains is crucial for effective and sustainable E-waste management.

9.1. Technological Advancements

Technological innovation forms a cornerstone of effective E-waste recycling. The results highlight significant potential in various processing methods and digital tools. Advanced recycling technologies, such as hydrometallurgical, bio-metallurgical, and pyrometallurgical processes, have demonstrated considerable potential in improving metal extraction efficiencies from E-waste. Hydrometallurgy, using chemicals to dissolve metals, can extract base metals and noble metals, and can be used in conjunction with solvent extraction and electrowinning for high purity recovery of metals like copper and REEs. Bio-metallurgical processes, such as bioleaching using microorganisms, offer an environmentally friendlier alternative for metal extraction, including from PCBs. Pyrometallurgy, involving high-temperature smelting, can be effective for certain metals, although it can be energy-intensive. The development and optimization of these technologies, including addressing reagent selection and waste management in hydrometallurgy, and improving microbial efficiency and scalability in bioleaching, are crucial.

On the other hand, utilizing industry 4.0 solutions (i.e., integration of digital technologies in recovery processes) offers significant opportunities for enhancing E-waste management. AI and machine learning (ML) can optimize leaching processes and improve the accuracy and robustness of automated disassembly and sorting using computer vision and deep learning. Robotics and automated disassembly can increase efficiency and reduce the hazards associated with manual dismantling. Internet of Things (IoT) and sensor-based monitoring can provide real-time data for process optimization. Digital twins can simulate and optimize recycling processes before physical implementation, enhancing efficiency and reducing risks. However, the full potential of these technological advancements can only be realized with supportive policy frameworks and active stakeholder engagement.

9.2. The Impact of Policy Interventions

Strategic policy interventions are essential to create an enabling environment for sustainable E-waste management. Examples are: (a) Implementing and effectively enforcing EPR programs holds producers accountable for the take-back and recycling of their products, incentivizing them to design for recyclability and invest in collection and treatment infrastructure. Inconsistencies in definitions and implementation across regions need to be addressed for greater effectiveness; (b) Clear and consistent regulatory frameworks at national and international levels are necessary to set recycling targets, ensure environmental compliance, and combat illegal waste exports. The Basel Convention plays a crucial role in regulating the transboundary movement of hazardous E-waste; (c) Deposit-refund schemes (DRS) have proven effective in increasing collection rates by assigning a monetary value to returned products. Other economic incentives, such as subsidies for sustainable recycling practices and taxes on unsustainable disposal methods, can further promote industry participation and consumer engagement.; and (d) The development of standardized recycling protocols can improve the efficiency and quality of material recovery processes. The effectiveness of these policies is contingent upon active participation from all stakeholders.

9.3. The Crucial Role of Stakeholder Engagement

Collaboration and participation across different stakeholder groups are vital for building a sustainable E-waste recycling ecosystem: (a) Beyond EPR schemes, manufacturers should be encouraged to incorporate recycled materials and modular designs and provide repair instructions and support services to extend product lifecycles and facilitate repair and reuse. Retailer take-back programs also provide convenient collection points for consumers; (b) Raising public awareness about the importance of proper E-waste disposal and providing convenient and accessible collection systems are crucial for increasing consumer participation in formal recycling programs. Understanding consumer behavior and motivations, as explored through models like the Theory of Planned Behavior (TPB) and the Norm Activation Model (NAM), is essential for designing effective engagement strategies; and (d) PPPs can leverage the resources and expertise of governments, businesses, and non-profit organizations to develop recycling infrastructure, improve waste collection systems, and formalize the informal E-waste sector. Integrating the informal sector is particularly important in developing economies.

The synergistic interaction of the three domains (i.e., technological advancements, policy interventions, and stakeholder engagement) is fundamental to achieving a resilient CE for electronics.

9.4. Proposed Implementation Roadmap

To effectively enhance the synergistic leverage for sustainable E-waste management, the proposed implementation roadmap (

Table 8. Implementation roadmap for E-waste sustainable management.

Step	Action	Key Stakeholders	Expected Outcome
1. Improve Recycling Infrastructure	❖ Invest in AI-powered sorting and robotics for automation	❖ Governments, Recycling Firms	❖ Higher efficiency, reduced labor risks
2. Implement Extended Producer Responsibility (EPR)	❖ Mandate electronics manufacturers to finance E-waste collection and recycling	❖ Government Regulators, Tech Industry	❖ Higher collection and recycling rates
3. Strengthen Consumer Awareness Campaigns	❖ Launch educational programs and incentives for responsible recycling	❖ NGOs, Tech Companies, Media	❖ Increased participation in recycling programs
4. Expand Public-Private Partnerships	❖ Encourage collaboration between government and private sector in E-waste recycling	❖ Municipal Authorities, Private Investors	❖ Increased funding and infrastructure expansion
5. Promote Eco-Design and left-to-Repair Laws	❖ Require manufacturers to produce repairable and recyclable devices	❖ Policy Makers, Tech Industry	❖ Reduced E-waste generation
6. Introduce CE Initiatives	❖ Encourage businesses to use recycled materials and modular design	❖ Corporations, Researchers	❖ Sustainable product life cycles

) can guide governments and industries. The first step is to invest in AI-powered recycling infrastructure to improve efficiency and material recovery. Next, EPR policies should be adopted to enforce manufacturer accountability. Consumer awareness campaigns should be strengthened through educational programs and incentives, encouraging responsible recycling behaviors. PPPs should be expanded to increase funding and infrastructure for E-waste management. Furthermore, eco-design regulations should be enforced to ensure that electronic products are built for longer life cycles and easier recycling. Lastly, businesses should be encouraged to incorporate recycled materials and modular designs, fostering a more sustainable electronics industry.

10. Data Variability and Limitations in E-Waste and Mineral Resource Management

10.1. Challenges

While the role of E-waste in sustainable mineral resource management is increasingly recognized, its full potential remains difficult to quantify due to significant data variability and limitations. These challenges hinder reliable assessments of material recovery potential, policy effectiveness, and the design of scalable circular economy models.

(1)

Inconsistent Definitions and Categorization: One major limitation arises from the lack of a universal definition of E-waste. Different countries and agencies classify electronic waste using varying criteria—some based on product type (e.g., large vs. small appliances), others based on material content or end-use. This lack of standardization affects how data is reported, making cross-country comparisons unreliable and complicating efforts to establish global baselines for E-waste generation, recovery rates, and mineral potential.

(2)

Underreporting and Informal Sector Exclusion: Globally, less than 20% of E-waste is formally collected and recycled [4,74]. However, this figure does not account for the large volumes of E-waste handled by the informal sector, particularly in Asia, Africa, and Latin America. Informal recycling contributes significantly to mineral recovery—especially for base and precious metals—but these activities are rarely tracked in national statistics. This leads to systematic underreporting of actual recovery volumes, distorting both environmental impact assessments and resource flow estimates.

(3)

Material Content Uncertainty: E-waste is highly heterogeneous in terms of composition, age, brand, and usage patterns, making it difficult to develop accurate estimates of recoverable materials. The concentration of high-value metals such as gold, palladium, and rare earth elements can vary widely across product types and production years. Without disaggregated data on specific product categories (e.g., smartphones vs. televisions), it is challenging to assess the true mineral resource value embedded in the E-waste stream.

(4)

Limited Geographic and Temporal Resolution: Data on E-waste generation and recycling is often aggregated at the national or regional level, lacking granular geographic resolution. Additionally, many countries report data at multi-year intervals, which fails to capture fast-changing trends in consumer electronics and recycling behavior. This reduces the ability to conduct timely resource planning or to track the effectiveness of newly implemented policies.

(5)

Gaps in Lifecycle and Traceability Data: Reliable management of E-waste as a sustainable mineral resource depends on the ability to track products throughout their lifecycle—from production to end-of-life disposal. However, many supply chains lack product traceability mechanisms such as digital product passports, serial number registries, or disposal logs. As a result, the precise location and condition of retired electronic goods often remain unknown, limiting opportunities for urban mining and secondary resource recovery.

(6)

Lack of Standardized Reporting Frameworks: There is currently no globally harmonized reporting protocol for E-waste collection, recycling, and material recovery. Different countries adopt different metrics, thresholds, and reporting agencies, resulting in fragmented datasets. Even within regions such as the EU, variations in implementation of the WEEE Directive lead to discrepancies in reported outcomes, impeding unified progress tracking.

10.2. Implications for Sustainable Mineral Resource Management

These data limitations have direct implications for the development of effective resource management strategies. Without accurate and consistent information: (a) Policymakers cannot reliably model secondary resource availability; (b) Investors lack the data needed to assess the economic viability of urban mining; (c) Manufacturers are unable to design effective take-back systems or recovery logistics; and (d) International organizations face challenges in evaluating the global impact of E-waste regulations or circular economy programs.

10.3. Recommendations to Address Data Gaps

To improve the role of E-waste in sustainable mineral resource management, the following steps are essential: (a) Adopt internationally standardized definitions and classification schemes for E-waste (e.g., via the ISO/IEC or UNEP); (b) Integrate informal sector data into national inventories through participatory mapping, incentives, and public-private partnerships; (c) Develop material flow analyses (MFAs) by product category to improve estimates of recoverable critical raw materials; (d) Implement digital tracking systems (e.g., blockchain, IoT-based tagging) to enhance product traceability from production to disposal; and (e) Establish harmonized reporting frameworks for E-waste at regional and global levels, modeled on the Intergovernmental Panel on Climate Change (IPCC) or the Global Reporting Initiative (GRI).

In summary, while E-waste holds significant promise as a source of secondary raw materials, data variability and reporting limitations remain substantial barriers. Addressing these issues is critical to unlocking E-waste’s full contribution to sustainable mineral resource management and achieving global circular economy goals.

11. Conclusions and Future Outlook

The pressing global issue of escalating E-waste generation, evidenced by a rise from 35.8 Mt in year 2011 to a projected 74.7 Mt by year 2030, underscores the urgent need for effective management strategies, especially considering the alarmingly low global recycling rate of just 17.4% in year 2019. This stark disparity between E-waste generation and recovery efforts highlights significant gaps in current E-waste management systems. These gaps include regulatory and policy inconsistencies across regions, technological limitations in efficiently recovering all valuable materials, economic disincentives that render primary mining more competitive in certain contexts, and insufficient consumer awareness and participation in formal recycling programs. The prevalence of informal recycling practices and illegal E-waste exports further exacerbate these challenges, leading to environmental and health concerns.

Based on the analysis presented in the paper, several avenues for future research in the field of E-waste management and critical mineral recovery can be recommended. These areas aim to address existing gaps and enhance the transition towards a more sustainable and CE for electronics.

(1)

Addressing under-researched areas: The review of publications highlighted that topics such as public engagement and the institutional and legal structures governing E-waste practices, and digital technologies and automation in E-waste management. Future research could focus on gaining a deeper understanding of the complex global flow of E-waste, including the dynamics of illegal exports and the environmental and social impacts in receiving countries. Investigating the geochemical aspects of metals in E-waste and their potential long-term environmental consequences would also be valuable. Furthermore, exploring the specific role of E-waste recycling in supporting the clean energy transition and the material requirements of renewable energy technologies warrants further investigation.

(2)

Optimizing existing recovery technologies: While various technologies for mineral recovery exist, there is room for improvement and optimization. Future research should focus on: (a) Enhancing the selectivity and efficiency of hydrometallurgical processes while minimizing the use of hazardous chemicals and improving wastewater treatment methods. Research into greener leaching agents and more efficient solvent extraction techniques is needed; (b) Reducing the energy consumption and air pollutant emissions of pyrometallurgical processes through innovative furnace designs and advanced emission control technologies; (c) Improving the efficiency and scalability of bio-metallurgical approaches to make them more viable for industrial applications. This includes optimizing microbial activity and developing cost-effective bioreactor designs; and (d) Further developing and integrating electrochemical processes with other methods to achieve high-purity metal recovery with minimal environmental impact and lower energy requirements. Investigating novel electrode materials and cell designs could be beneficial.

(3)

Advancing automation and digitalization: The integration of Industry 4.0 solutions holds significant potential for E-waste management. Future research could focus on: (a) Developing more sophisticated AI and machine learning algorithms for improved automated disassembly and sorting of complex electronic devices; (b) Exploring the use of digital twins to simulate and optimize entire E-waste recycling processes before physical implementation, thereby enhancing efficiency and reducing risks; (c) Investigating the application of blockchain technology for enhancing the traceability and transparency of the E-waste supply chain; and (d) Addressing the significant gap between E-waste generation and recycling requires better collection systems. Future research could explore: (i) Developing and evaluating the effectiveness of different take-back schemes and deposit-refund systems in various socio-economic contexts; (ii) Investigating the role of digital technologies and IoT in optimizing reverse logistics networks and improving collection rates; and (iii) Identifying and addressing the barriers to consumer participation in formal recycling programs through behavioral studies and targeted interventions.

(4)

Policy and economic frameworks: Research into effective policy interventions and economic incentives is crucial for driving the CE for electronics. This includes: (a) Analyzing the impact and effectiveness of different EPR models and identifying best practices for implementation and enforcement. Research should address inconsistencies in definitions and implementation across regions; (b) Investigating the role of economic incentives, such as subsidies, tax breaks, and material recovery credits, in making E-waste recycling more financially competitive with primary mining; and (c) Developing harmonized international standards and regulations for E-waste management to combat illegal exports and promote responsible recycling practices globally.

By focusing on these research areas, the scientific community can contribute significantly to developing more sustainable, efficient, and economically viable solutions for managing the growing challenge of electronic waste and securing the supply of critical raw materials