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Urban Mining of E-Waste is Becoming More Cost-Effective Than Virgin Mining
Abstract
Stocks of virgin-mined materials utilized in linear economic flows continue to present enormous challenges. E-wastes are the fastest growing waste streams, and threaten to grow into a global problem of unmanageable proportions. An effective form of management of resource recycling and environmental improvement is available, in the form of extraction and purification of precious metals taken from waste streams, in a process known as urban mining. We demonstrate utilizing real cost data from e-waste processors in China that ingots of pure copper and gold may be recovered from e-waste streams at a cost that makes urban mining economically more attractive than virgin mining. When these results are generalized across different metals and countries, they promise to have widespread beneficial effects on waste disposal as well as important repercussions on mining activities globally, as the circular economy comes to displace linear economic pathways.
... The nodes with the same color represent the same cluster. From the figure, it can be seen that five small groups only cooperate closely with a certain group and no cooperation with other groups, Among them, Jinhui Li and Xianlai Zeng from Tsinghua University formed a cooperative group mainly to research the sustainability of critical metals and e-waste management (Li et al. 2013(Li et al. , 2015a(Li et al. , 2015bZeng et al. 2015Zeng et al. , 2018; a collaborative group mainly formed by Professor Kawakita of Kyushu University in Japan to research the smelting, separation, and extraction of critical metals in the field of chemical engineering and the recycling of metal-containing electronic waste (Kawakita et al. 2010); another cooperative group mainly formed by Professor Anwande from the University of Tubingen in Germany and Professor Deacon from Monash University in Australia to study transition metal compounds, metal-based catalysts, and crystal structures (Anwander et al. 2017;Deacon et al. 2017); a third collaborative group for the study of metal biosorption and recovery of rare and precious metal resources was formed by Professor Yeoung-Sang Yun from Chonbuk University in Korea and Associate Professor Juan Mao from Huazhong University of Science and Technology (Mao et al. 2020, Yun andVolesky 2003); the fourth cooperative group researching rare earth metal-organic compounds was mainly led by researcher Dongmei Cui of the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Liu et al. 2021); other cooperative groups connected with it are mainly researching the application of critical metals in the fields of polymer materials, nanomaterials, environmental materials, and chemistry and chemical engineering. ...
... From this topic, it can be found that scholars are mainly focusing on e-waste to research critical metals. Many scholars concentrate on recycling e-waste management, sustainability of metal resources, and urban mines (Li et al. 2013(Li et al. , 2015aZeng et al. 2018). The other part of scholars focuses on the extraction of critical metals (gold, silver, platinum, molybdenum, vanadium, tungsten, cobalt, chromium) in the field of chemical engineering, smelting, separation, extraction, and recovery of metals from end-of-pipe e-waste (Kawakita et al. 2010;Mao et al. 2020). ...
Critical metals are indispensable to a world seeking to transition away from carbon. Yet their extraction, processing, and application leave an unsustainable global environment and climate change footprint. To capture the development dynamics and research emphases of critical metals throughout their life cycle, this paper adopts bibliometrics to analyze the various stages of global critical metal flow in multiple dimensions to reveal the hot issues and future strategic trends. The research results indicate that the number of research papers on critical metals is annually rising, with remarkably rapid growth after 2010. Judging from the number of articles published by the authors and the citations, among the authors, Kawakita, Poettgen, Anwander, Inoue, and Dongmei Cui have a significant influence on critical metal research fields. The institutions with the most research on critical metals are universities, not research institutes. In addition, the focus has extended from a single discipline to the interdisciplinary development of multiple disciplines. Analysis of keywords shows that “rare metals” and “precious metals” are the most popular metals among the researched metals. The researched buzzwords of critical metals are disappearing, convergent, and merging over time. The research has focused on the mining and the whole life cycle process of extraction, treatment, and application. Based on the above characteristics, this paper tries to understand the dynamic development and evolution of global critical metals from multiple dimensions, resorting to giving a reference for follow-up-related research scholars.
... From the viewpoint of empirical analysis, China provides a particularly interesting context, given its highly centralized governance structure and massive efforts for promoting innovation-oriented growth (Li 2018). On the one hand, in China, the government controls the allocation of resources to a large degree, which leaves rooms for high-level bureaucracy and strong regulations in certain areas, such as market entry and financial control. ...
... Discussions of these cases can be found inMathews (2013Mathews ( , 2016Mathews ( , 2018.18 Cases in China are discussed in Tan (2014, 2016);Mathews et al. (2018); andZeng et al. (2018). ...
It is great to launch these conference proceedings from the ISS 2018 conference held in Seoul, July 2–4, Korea. The theme of the ISS 2018 was “Innovation, Catch-up, and Sustainable Development. Keun Lee, one of the guest editors of this volume, served as the President of the Society (2016–2018) and also as the main host or Chairman of the Organizing Committee, for the Seoul conference. Actually, it took 26 years to return to Asia: the last ISS conference in Asia was held in Kyoto, Japan, in 1992. And it turned out to be a good decision for the International Schumpeter Society to return to Asia: About 380 papers were presented out of the 469 initial submissions from more than 50 nations around the world. Among these 380 presentations, there were about 90 papers presented by young scholars who are either graduate students or new Ph.D. students.
... From the viewpoint of empirical analysis, China provides a particularly interesting context, given its highly centralized governance structure and massive efforts for promoting innovation-oriented growth (Li 2018). On the one hand, in China, the government controls the allocation of resources to a large degree, which leaves rooms for high-level bureaucracy and strong regulations in certain areas, such as market entry and financial control. ...
... Discussions of these cases can be found inMathews (2013Mathews ( , 2016Mathews ( , 2018.18 Cases in China are discussed in Tan (2014, 2016);Mathews et al. (2018); andZeng et al. (2018). ...
This volume presents selected contributions from the 2018 conference of the International Schumpeter Society (ISS). The selected chapters in this volume reflect the state-of-the-art of Schumpeterian economics dedicated to the three conference topics innovation, catch-up, and sustainability. Innovation is driving catch-up processes and is the condition for a transformation towards higher degrees of sustainability. Therefore, Schumpeterian economics has to play a key role in these most challenging fields of human societies’ development in the 21st century. The three topics are well suited to capture the great variety of issues, which have the potential to shape the scientific discussion in economics and related disciplines in the years to come.
The presented contributions show the broadness and high standard of Schumpeterian analysis. The ideas of dynamics, heterogeneity, novelty, and innovation as well as transformation are the most attractive fields in economics today and offer the most prolific interdisciplinary connections now and for the years to come when humankind, our global society, has to master the transition towards sustainable economic systems by solving the grand challenges and wicked problems with which we are confronted today.
Therefore, the book is a must-read for scholars, researchers, and students, interested in a better understanding of innovation, catch-up, and sustainability, and Schumpeterian economics in general.
... Copper smelting at about 1200-1350 °C, followed by converting and fire refining, is widely used for the commercial recycling of geochemically scarce elements present in complex end-of-life electric and electronic equipment. The presence of relatively valuable elements (such as Au, Ag and Pt-group metals) in the outputs of mining complex end-of-life products can be conducive to the recovery of other geochemically scarce elements by pyrometallurgy (Zeng, Mathews and Li 2018). A potential trade-off between the recoveries in pyrometallurgy, when more than one element is recovered, has been reported for Pd and Ge (Shuva et al. 2017). ...
... Dreisinger 2016; Lasheen et al. 2015;Sole et al. 2019). Pyrometallurgical co-processing of copper concentrates with mined end-of-life electric and electronic equipment can increase financial returns (Knapp 2018;Zeng, Mathews and Li 2018). Generating extracted matrix materials from ore processing residues which can be applied in construction and building materials may have financial benefits (e. g. ...
Copper ores, end-of-life electric and electronic equipment and car electronics can contain, besides Cu, substantial amounts of geochemically scarce companion elements. Geochemically scarce elements have an upper crustal abundance of <0.025 (weight)%. In view of resource conservation and reduction of pollution there is a case for near-zero waste processing. Improving the generation of ore concentrates and use of kinetic and thermodynamic data regarding smelting and converting can increase the production of geochemically scarce elements in the pyrometallurgical processing of copper ores. Reprocessing of copper ore processing residues can serve the generation of geochemically scare elements and the clean-up of matrix materials. Modularization of products, closed-loop take-back, including deposit-refund, systems for end-of -life products, and changes in the pre-processing thereof can be conducive to improved recovery of geochemically scarce elements from end-of-life electric and electronic equipment and car electronics. A comparatively large variety of geochemically scarce elements originating in end-of-life products can be recovered when in smelting lead and copper serve as collectors. Substantial research and development work is needed to optimize the co-production of geochemically scarce elements by hydrotechnology from copper ores and (mined) end-of-life products and to assess the potential of solvochemistry. There is technical scope for significant progress in the direction of near-zero waste processing in processing copper ores and (mined) end-of-life products, but for the realization of near-zero waste processing there are hurdles to be overcome related to marketability of outputs, safe handling of hazardous elements and company behavior. Also, the techno-economic potential of hydrotechnology and solvochemistry in extracting copper ores, copper ore processing residues and end-of-life products is uncertain. In view thereof, the feasibility near-zero waste production of copper and its geochemically scarce companion elements from copper ores and end-of-life electric and electronic equipment and car electronics is uncertain.
... Glass, plastics, copper, aluminum, silver, palladium and gold are most often recovered from e-waste and can be used to produce printed circuit boards (PCB) and electronic components (Kaya, 2016). The recovery of strategic metals from e-waste can be almost seven times cheaper than their extraction from ores (Zeng et al., 2018). A thousand kilograms of spent mobile phones contains about 150 g of gold (more than in a ton of copper ore in which Au occurs), 100 kg of copper and 3 kg of silver. ...
As the recovery, conversion and reuse of metals is a crucial concept of waste-to-resources (WTR) within a circular economy, the study was undertaken to check the effectiveness of using a new leaching system, containing hydrogen sulfate ionic liquids (with dimethyloctylammonium (IL1), 1-octylimidazolium (IL2) or 2-methyl−1-octylimidazolium (IL3) cations) to dissolve Cu(II) from e-waste, i.e. printed circuit boards (PCBs). Metal (Cu(II), Ag(I), Au(III)) leaching was attempted with 0.5 M IL solutions with or without the addition of H2O2 (an oxidant) for 3 h at 23 or 75 °C and at the solid to liquid ratio (S/L) of 1/20 g/cm³. No Au(III) and very small amounts of Ag(I) were determined in the leach liquor (leachate). Therefore the discussion and ANOVA analysis of the leaching results were performed only for Cu(II). It is shown that the ILs can be used as the leaching media but need the presence of an oxidant to leach high amounts of Cu(II) from e-waste. For example, the presence of IL1 was found to improve the leaching efficiency of the oxidant (H2O2) when compared to the leaching at pH ~ 1 without IL. These experimental results were confirmed by the ANOVA analysis, showing that the presence of H2O2 is the main statistically significant factor responsible for the efficient Cu(II) leaching in this system.
... Although a recently released report by the United Nations University in Responsible Editor: Philippe Garrigues Bonn documented a decline in E-waste generation during the first three quarters of 2020, the scientists involved in that research have noted it likely to be temporary. 2 As a rapidly growing waste stream, E-waste threatens to emerge as a global problem of incontrollable magnitude (Zeng et al. 2018). Nevertheless, the Global South is disproportionately challenged by this increasing E-waste volume owing to several factors specific to those regions. ...
Globally, E-waste is experiencing an unprecedented growth in the recent years. This growth will be fueled further by the COVID-19 pandemic owing to the new work culture where people are becoming more dependent on their electronic products than ever before. However, governance of E-waste, particularly in the Global South, has been a complex phenomenon. Considering this, the current study attempted to assess the design, adoption, and implementation of E-waste policies in India—a major electronics manufacturing hub with a massive consumer electronics market. Taking hints from theoretical concepts such as policy transfer, policy convergence, and policy effectiveness, the study addressed the primary research question: why India adopts E-waste policy approaches that seem inadequate and ineffective in its local contexts and attempts to identify alternative approaches. Through expert interviews and policy document analysis, it was observed that E-waste policy approaches in India are largely influenced by the European Union’s Waste Electrical and Electronic Equipment (WEEE) Directive. All the experts interviewed recognized absence of the informal sector in India’s policy efforts of both 2011 and 2016 as a significant lacuna in the country’s E-waste policy responses. In this paper, the author argues that there should be policy change towards a healthy collaboration between the informal and formal sector where best-of-the-two-worlds could be wisely used for sustainable E-waste governance in India.
Graphical abstract
... But private governance mechanisms, or 'civil regulation' 115 , can complement them through voluntary standards, codes of conduct and certification, adapted to diverse contexts and supply chains aimed at minimizing the global production of inequities. Closed-loop supply chains based on circular economy ideas 116 , as well as advancements in metallurgy, waste separation, materials science, waste processing and advanced recycling, can all enhance the longevity and continual reuse of minerals and metals 117 . Researchers estimate that 65% of the domestic cobalt demand in the USA by 2040 could be supplied by end-of-life lithium ion batteries, provided a robust take-back and recycling infrastructure is in place 118 . ...
The world must ambitiously curtail greenhouse gas emissions to achieve climate stability. The literature often supposes that a low-carbon future will depend on a mix of technological innovation—improving the performance of new technologies and systems—as well as more sustainable behaviours such as travelling less or reducing waste. To what extent are low-carbon technologies, and their associated behaviours, currently equitable, and what are potential policy and research implications moving forward? In this Review, we examine how four innovations in technology and behaviour—improved cookstoves and heating, battery electric vehicles, household solar panels and food-sharing—create complications and force trade-offs on different equity dimensions. We draw from these cases to discuss a typology of inequity cutting across demographic (for example, gender, race and class), spatial (for example, urban and rural divides), interspecies (for example, human and non-human) and temporal (for example, future generations) vulnerabilities. Ultimately, the risk of inequity abounds in decarbonization pathways. Moreover, low-carbon innovations are not automatically just, equitable or even green. We show how such technologies and behaviours can both introduce new inequalities and reaffirm existing ones. We then discuss potential policy insights and leverage points to make future interventions more equitable and propose an integrated research agenda to supplement these policy efforts. Low-carbon innovations in technology and behaviour are increasingly prevalent, but they are not always equitable. This Review examines how such innovations can introduce and perpetrate inequalities, and discusses ways to ensure that a low-carbon future is both sustainable and equitable.
... With the non-renewable characteristics, limited supply and everincreasing market demand of precious metal resources in mind, tremendous attention has been attracted to gold recovery from e-waste in order to reduce the dependence on the existing mineral resources and address potential environmental risks as well as achieve the sustainable circular economy target. 4,5 To efficiently extract gold from e-waste, various recovery techniques have been developed, such as pyro-and hydro-metallurgical processes, solvent extraction, chemical precipitation, ion exchange, electrolysis, and adsorption. 1,6 Among them, adsorption has been recognized as the most reliable means due to its easy operation, low cost, and high efficiency. ...
The ever‐growing depletion of precious metals in modern electronic industry necessitates unremitting exploitation of novel materials for gold recovery from e‐waste. Herein, a freestanding poly(imine dioxime) (PIDO) membrane has been successfully fabricated for highly efficient recovery of gold from e‐waste. The consummate integration of abundant binding sites and hierarchically porous architecture renders the resulting PIDO membrane with a record‐breaking uptake capacity (9250 mg g−1) toward gold, fast adsorption equilibrium time, as well as satisfactory regeneration and reusability. Furthermore, PIDO membrane is also well competent for selective gold recovery from waste central processing unit leachate with remarkable efficiency (>99%). Considering high recovery efficiency, outstanding selectivity, and simple/scalable production process, the proposed PIDO membrane will hold huge prospect in the sustainable recovery of gold from e‐waste. A freestanding, hierarchically porous Poly(imine dioxime) membrane is fabricated via a simple evaporation‐induced self‐assembly technique based on the Marangoni effect. The resulting PIDO membrane demonstrates excellent gold recovery performance, including record‐breaking capacity, ultrafast kinetics, superior selectivity, outstanding regeneration and reusability. The work paves the way for the sustainable recovery of gold from e‐waste in an economical and feasible means.
... For the EU, most of the data are related to the Use and EoL phases of waste electrical and electronic equipment (WEEE), and portable batteries. Since the 2000s, the EU has been one of the main actors on WEEE recycling, together with the USA, Japan, and China (Melin, 2018;Zeng et al., 2018). WEEE and Battery directives entered into force in 2003 and 2006, respectively, in order to develop schemes that arrange collection and further transportation of waste to recycling facilities (European Commission, 2018a; European Commission, 2018h). ...
... The concomitant increment in metal demand and paucity of primary resources is an emerging challenge for valuable metal production [1,2]. In this regard, urban mining aimed towards green recycling and recovery of metals from electronic waste (e-waste) has been gaining momentum [3,4]. Additionally, the metal recycling approaches are also receiving crucial attention from the United Nations Environment Program (UNEP), since the worldwide demand for metals has been mounting consistently [5,6]. ...
There is a growing interest in electronic wastes (e-wastes) recycling for metal recovery because the fast depletion of worldwide reserves for primary resources is gradually becoming a matter of concern. E-wastes contain metals with a concentration higher than that present in the primary ores, which renders them as an apt resource for metal recovery. Owing to such aspects, research is progressing well to address several issues related to e-waste recycling for metal recovery through both chemical and biological routes. Base metals, for example, Cu, Ni, Zn, Al, etc., can be easily leached out through the typical chemical (with higher kinetics) and microbial (with eco-friendly benefits) routes under ambient temperature conditions in contrast to other metals. This feature makes them the most suitable candidates to be targeted primarily for metal leaching from these waste streams. Hence, the current piece of review aims at providing updated information pertinent to e-waste recycling through chemical and microbial treatment methods. Individual process routes are compared and reviewed with focus on non-ferrous metal leaching (with particular emphasis on base metals dissolution) from some selected e-waste streams. Future outlooks are discussed on the suitability of these two important extractive metallurgical routes for e-waste recycling at a scale-up level along with concluding remarks.
... It is argued that a shift to resource recovery through e-waste recycling is becoming more cost-effective compared to conventional virgin mining and that the grade and concentration of metals in e-waste can be higher than that extracted from ores. [10]. ...
Abstract In the face of a burgeoning stream of e‐waste globally, e‐waste recycling becomes increasingly imperative, not only to mitigate the environmental and health risks it poses but also as an urban mining strategy for resource recovery of precious metals, rare Earth elements, and even plastics. As part of the continual efforts to develop greener alternatives to conventional approaches of e‐waste recycling, biologically assisted degradation of e‐waste offers a promising recourse by capitalising on certain microorganisms' innate ability to interact with metals or degrade plastics. By harnessing emerging genetic tools in synthetic biology, the evolution of novel or enhanced capabilities needed to advance bioremediation and resource recovery could be potentially accelerated by improving enzyme catalytic abilities, modifying substrate specificities, and increasing toxicity tolerance. Yet, the management of e‐waste presents formidable challenges due to its massive volume, high component complexity, and associated toxicity. Several limitations will need to be addressed before nascent laboratory‐scale achievements in bioremediation can be translated to viable industrial applications. Nonetheless, vested groups, involving both start‐up and established companies, have taken visionary steps towards deploying microbes for commercial implementation in e‐waste recycling.
... Thus, it is necessary to develop technological routes and managements policies to consolidate the recycling of WEEE to recover valuable materials [18]. High levels of metal recovery from WEEE have been reported and the costs associated with it are becoming more competitive but are still higher than those associated with mining operations [5,19]. In terms of economic potential in Brazil, a previous work from our research group estimated, based on a population survey and mass balance, that the stockpile value of devices in hibernation could be as high as USD 797 million [20]. ...
The production of electronic waste due to technological development, economic growth and increasing population has been rising fast, pushing for solutions before the environmental pressure achieves unprecedented levels. Recently, it was observed that many extractive metallurgy alternatives had been considered to recover value from this type of waste. Regarding pyrometallurgy, little is known about the low-temperature processing applied before fragmentation and subsequent component separation. Therefore, the present manuscript studies such alternative based on scanning electron microscopy characterization. The sample used in the study was supplied by a local recycling center in Rio de Janeiro, Brazil. The mass loss was constant at around 30% for temperatures higher than 300 °C. Based on this fact, the waste material was then submitted to low-temperature processing at 350 °C followed by attrition disassembling, size classification, and magnetic concentration steps. In the end, this first report of the project shows that 15% of the sample was recovered with metallic components with high economic value, such as Cu, Ni, and Au, indicating that such methods could be an interesting alternative to be explored in the future for the development of alternative electronic waste extraction routes.
... Thus, technologies that can stably secure strategic metals should be developed. Consequently, urban mining, which recovers strategic metals from secondary sources, has attracted substantial attention (Nie et al., 2015;Sun et al., 2016;Wang et al., 2017;Zeng et al., 2018). Secondary sources such as spent lithium-ion batteries (LIBs) are considered valuable urban mining resources Nie et al., 2015;Shi et al., 2018;Zeng et al., 2015). ...
A simple, green approach to recover NiMnCoC2O4 as an electrode material for high-performance pseudocapacitors from spent LiNiMnCoO2 (NMC) batteries is proposed. Four strategic metals (Li, Ni, Co, and Mn) were leached from spent NMC batteries using several organic acids as model green leachants. Among the various candidates of green leaching agents, 2 M citric acid and 5 wt% glucose were selected as the leachant and reductant, respectively. Microwave irradiation was conducted during the leaching step to maximize the performance of the leaching rate and efficiency. The leaching efficiencies within 0.5 h for Ni(II), Li(I), Mn(II), and Co(II) were 90.7±1.6%, 98.3±2.4%, 94.9±4.3%, and 95.6±1.4%, respectively, and were thus as efficient as using aqua regia leaching. After the leaching process, divalent metal ions, that is, Ni(II), Co(II), and Mn(II), were immediately separated at room temperature using oxalic acid. The recovered samples were not further treated and used directly for energy storage applications. The recovered NiMnCoC2O4⋅nH2O has been demonstrated as a promising electrode for pseudocapacitors, providing a specific capacitance of 1,641 F/g, good rate-retention capability (80% of low-current capacitance), and good cycle stability over 4,000 charge–discharge cycles.
... First Solar reports a recovery rate of up to 90% for end-of-use/life semiconductor material and glass for use in new modules [26], and their capacity is scalable to adapt to the coming surge of PV product returns. Sourcing valuable components and elements (usually from waste electrical and electronic equipment (WEEE)) has been labeled "urban mining" [27], and can be more cost-effective than traditional mining options, as those investments have lagged behind demand projections. Indeed, the constraint here is less that the materials are not suitable or are of inappropriate quality, but that (with the exception of First Solar) the return and collection infrastructure has not yet been suitably developed to support such ventures. ...
Energy demand continues to grow with the world’s burgeoning population. Meeting energy needs through renewable sources allows for market growth with limited environmental impact, but sourcing constraints can limit production, creating industrial and environmental problems. The exploitation of end-of-use and end-of-life photovoltaic (PV) options that are traditionally treated as waste offers a valuable opportunity to support renewable energy market growth with fewer sourcing constraints and minimal environmental impacts, but this circular investment has not yet been broadly implemented, nor is broad guidance widely available to aid its implementation. From a business perspective, this paper discusses the technical issues, assesses the anticipated market growth issues, and proposes a combination of circular economy, industrial ecology, and process integration principles to contribute a theoretically supported, practical framework to improve the management of end-of-use/life PV products and support renewable energy market growth.
... For example, used PCBs contain almost up to 350 mg of gold per kilogram of PCBs, which is known to be 100 times more than that contained in gold ore (Cui & Zhang, 2008). Above all, it is reported that conventional mining for different metals like copper, lead, aluminum, gold and silver costs around 13 times and 7 times more than the expense of recycling cathode ray tubes and printed circuit boards (PCBs), respectively (Zeng et al., 2018). ...
Decrease in life span of electronic devices and consumer’s urge to use advanced technology leads to obsolescence of such devices, resulting in electronic waste generation. The technology for e-waste components recycling has made great progress. However, due to growing environmental concern, there is a need to find alternatives for conventional e-waste recycling methods to achieve a safer environment. Rapid surge in e-waste generation is a matter of concern due to elevated levels of heavy metals and persistent organic pollutants (POPs) in air, soil and water caused by informal recycling practices. Moreover, recycling of printed circuit board (PCB), a major part of electronic waste, in order to recover metals, results in release of waste acid leach water, if untreated, which contain heavy metals like Pb, Cr, Ni, etc. This has given rise to the development of several remediation techniques for soil- and water-like phytoremediation, soil washing, bioremediation, and application of nanoparticles, which have been compared and reviewed in this paper along with their limitations for application at larger scale for real-contaminated soil. This review focuses on the existing remediation techniques and their limitations to decrease environmental hazards caused by the release of various pollutants through e-waste recycling.
Graphic abstract
... For instance, (Hagelüken, 2013) estimated that the concentration of precious and rare earth elements in electronic waste (e-waste) is at least a hundred times more compared to natural ores, and several other studies investigate landfills as potential urban mines for these metals (Ueberschaar et al., 2017), (Marra et al., 2018). Furthermore, recent papers showed that recovering valuable metals from waste electronic and electrical equipment (WEEE) is more cost-effective than mining and extracting from natural ores (Zeng et al., 2018). ...
Smartphones enable the function and evoluation of modern society. However, with a compressed product life cycle and growing consumer demand, a significant number of smartphones reach End-of-Life (EoL) annually. At the same time, due to many unique physical properties, rare earth elements (REE), critical, platinum group metals (PGMs) and other important metals are key for the manufacturing of smartphones. Hence, from various economic, sustainable resource management and environmental perspectives, it is crucial to understand how the metal content of different smartphones generations change over time. This study provides a detailed analysis of a high production smartphone series, produced between 2010 and 2015. Devices were first disassembled and their printed circuit boards assembly, back cameras and near field communication/wireless charging parts were analyzed for 60 elements, 30 of which are classified as environmentally critical. Results indicate that up to 70% of the three analyzed smartphone components by weight are important recyclable metals. The highest concentration elements, Cu, Ni, Sn, Zn and Fe, accounted for 93.3% while REEs and PGMs collectively accounted for 0.53% of the total recoverable elements by weight. The cradle-to-gate environmental impacts will vary proportionally based on temporal changes in elemental composition.
... In recent years, the management of Waste from Electrical and Electronic Equipment (WEEE) is becoming more and more challenging due to its growing volume rate [1]. WEEE waste streams require special treatment and sometimes complex management activities due to their intrinsic potential toxicity for the environment and their harmfulness to human and animal health [2]. ...
In this work, the application of Short-Wave Infrared (SWIR: 1000–2500 nm) spectroscopy was evaluated to identify plastic waste containing brominated flame retardants (BFRs) using two different technologies: a portable spectroradiometer, providing spectra of single spots, and a hyperspectral imaging (HSI) platform, acquiring spectral images. X-ray Fluorescence (XRF) analysis was preliminarily performed on plastic scraps to analyze their bromine content. Chemometric methods were then applied to identify brominated plastics and polymer types. Principal Component Analysis (PCA) was carried out to explore collected data and define the best preprocessing strategies, followed by Partial Least Squares—Discriminant Analysis (PLS-DA), used as a classification method. Plastic fragments were classified into “High Br content” (Br > 2000 mg/kg) and “Low Br content” (Br < 2000 mg/kg). The identified polymers were acrylonitrile butadiene styrene (ABS) and polystyrene (PS). Correct recognition of 89–90%, independently from the applied technique, was achieved for brominated plastics, whereas a correct recognition ranging from 81 to 89% for polymer type was reached. The study demonstrated as a systematic utilization of both the approaches at the industrial level and/or at laboratory scale for quality control can be envisaged especially considering their ease of use and the short detection response.
... S12B), corresponding to Y/Y 0 ~ 177% of that from the BR raw materials (Fig. 4B). The mechanism of the improvement of REE extractability from BR by the FJH process is presumed to be similar to that of CFA (Fig. 3), because phosphate is also one of the dominant counterions for BR (43). ...
Rare earth elements (REEs) are critical materials in electronics and clean technologies. With the diminishing of easily accessible minerals for mining, the REE recovery from waste is an alternative toward a circular economy. Present methods for REE recovery suffer from lengthy purifications, low extractability, and high wastewater streams. Here, we report an ultrafast electrothermal process (~3000°C, ~1 s) based on flash Joule heating (FJH) for activating wastes to improve REE extractability. FJH thermally degrades or reduces the hard-to-dissolve REE species to components with high thermodynamic solubility, leading to ~2× increase in leachability and high recovery yields using diluted acid (e.g., 0.1 M HCl). The activation strategy is feasible for various wastes including coal fly ash, bauxite residue, and electronic waste. The rapid FJH process is energy-efficient with a low electrical energy consumption of 600 kWh ton-1. The potential for this route to be rapidly scaled is outlined.
... Many more people in the community are likely to benefit economically from e-waste activities, including scrap buyers, sellers of e-waste products, persons engaged in electronic repair, and others. Given the need to subsidize formal recycling to generate a profit (Zeng et al., 2018), the informal sector may contain lessons for profitability of e-waste recycling. ...
The informal e-waste recycling sector has potential for both harmful environmental releases and environmental benefits associated with avoided emissions from recovered materials. Four household appliances (washing machine, refrigerator, Cathode Ray Tube (CRT) television, fan) were selected for a combined Material Flow Analysis and Life Cycle Assessment (LCA) analysis of their end-of-life treatment. Data collection took place in an informal e-waste recycling community in Thailand, recording the weight of materials recovered for each appliance, along with the number of each appliance recycled for one entire village. The LCA determined the avoided emissions and damages (human health, ecosystem quality, climate change, and resource use) per kg material recovered, per product, and for an entire recycling community, with a benefit of 2.7 to 25.4 kg CO2 eq avoided per product piece. Informal e-waste recycling appears relatively efficient in material recovery and economically beneficial. Recyclers recovered 93% or more of the original mass of the products. Just over 460,000 kg of waste devices were processed each year, with a net value added of 2.1 million Thai Baht. Each year, the normalized environmental net benefits amount to 0.2 DALYs for human health, 60,000 kg CO2 eq in climate change impacts, and nearly 400,000 MJ in avoided resource damages each month. Informal e-waste recycling was found to have net benefits in terms of avoided emissions, in particular due to recovery of PCBs, copper, steel and plastic with the exception of improper disposal of hazardous materials of lead in landfilled CRT screens and burned cables.
... Urban mining is such a practice (Izatt et al., 2014;Izatt and Hagelüken, 2016;Krook et al., 2012;Morf et al., 2013;Tunsu et al., 2015), supporting CE principles while being more cost-effective than market value (Ghisellini et al., 2016;Preston, 2012). This is true for elements like copper and gold, which usually are found unmixed in electronic products (Zeng et al., 2018). On the other hand, REE are found extremely dilute in technological products (Izatt et al., 2014). ...
Metals, including rare earth elements (REE), are the cornerstone of our current and future low-carbon urban infrastructure. This study looks at different waste resources and contaminated materials present in the urban setting as REE sources. Wastes and other dilute sources such as incineration ashes, sediments, and mine tailings are not only essential sources of REE in achieving a circular, carbon-neutral economy but may be the most realistic one. E-waste, being the most REE concentrated waste, faces serious reservations regarding handling in large-scale facilities, and this waste is generally landfilled. In this study, we analyzed REE total concentrations and pH desorption curves in ten dilute sources of REE: Ferrochrome slag from a mine in South Africa, sediments retrieved form stormwater ponds in Denmark, coal fly ashes, municipal solid waste (MSW) fly ashes, wood fly and bottom ashes and sewage sludge fly ashes (ashes from different sources). After analyzing different residues, we found that coal fly ashes and stormwater retention pond sediments present the most promising ones. While coal fly ashes have the highest critical REE contents from the studied wastes, the sediments collected from a stormwater retention pond showed the highest REE leachability. We can find Nd, Dy, and Er – all critical REE – in sediments/soils near highways, coal ashes, and bauxite residue. Overall, coal fly ashes contain the highest critical REE contents found in the studied wastes but sediments collected from stormwater water ponds present the highest leachable REE. In fact, up to 100% of total REE found in these sediments are leachable at room temperature and low pH. Future REE resource extraction efforts should account for REE speciation in wastes and not only total contents.
... imposed by increasing demand and scarcity of primary resources have led to great interest in urban mining.[226][227][228] Urban mining involves recovering critical metals from the waste of electronic and electrical equipment (WEEE) through a sustainable recycling process. ...
The optimization of the extraction processes requires a thorough analysis of the thermodynamic and kinetic features of the system. While there is considerable amount of literature on the equilibrium aspects of solvent extraction of metals, there is much less information available on the extraction kinetics. In this thesis we characterized the extraction kinetics of Pd(II), Nd(III) and Fe(III) with two malonamides of the same molecular formula but different topologies: N,N,N’,N’- tetrahexylmalonamide (THMA) and N,N,N’,N’- dimethyldibutyltetradecylmalonamide (DBMA). A thermodynamic characterization of the extraction systems was first carried out, and THMA proved to be very selective for the extraction of Pd(II) compared to DBMA. The characterization of the extraction kinetics was performed using the single drop technique, where the global transfer constants of Pd(II), Nd(III) and Fe(III) in the extraction with THMA and DBMA were determined. The study was further developed to determine the extraction rate laws of the systems. For this purpose, an experimental methodology based on the initial rate method, in small scale batch experiments was implemented for a fast and reliable screening of the extraction kinetics. Proceeding with this methodology, we could highlight the differences of the extraction kinetics of Pd(II) with THMA and DBM. The correponding extraction mechanisms were proposed. Finally, screening of extraction kinetics in batch experiments demonstrated the benefit of excess dihexylamine (DHA) employed during THMA preparation through a gain in kinetics performance. Thus, a performing molecular system for the extraction of Pd(II) with THMA was established. Altogether, this work has highlighted the interest of mastering the kinetics of solvent extraction for the development of selective processes of separation.
... 6 Thus, by taking into consideration that the value of raw materials in the global e-waste sector is approximately $57 billion USD 2 -with iron, copper and gold contributing the most to this value, these features render PCBs as an attractive 'urban mineral resource' for metal recovery. 7 Pyro-and hydrometallurgy are the primary processing route for the recovery of metals from waste PCBs, yet material processing operations are still required to first separate reusable and hazardous component from these materials. This process is carried out manually due to the diversity of connections mounted on PCBs, e.g., socket pedestal, through-hole device, surface mounted device, screw joint, and rivet. ...
Due to their high metal content, printed circuit board (PCBs) are an attractive resource for metal recovery. Until now, the dissolution and subsequent recovery of metals from PCBs considers either...
... The economic and environmental benefits of recycled materials relative to primary resources have been studied. Results show that the former is more environmentally friendly (Dewulf et al., 2015;Zeng et al., 2018). Therefore, some studies have advocated replacing the latter with the former (Hilton et al., 2019). ...
Challenges exist in life cycle assessment (LCA) to evaluate resource efficiency and environmental impacts of circular economy systems. Rules attributing recycling benefits/burdens are inconsistent, causing system boundary ambiguity. Besides, LCAs covering one or several life cycles fail to capture the complete resource path, which leads to unfair assessment results for the primary life cycle. This paper develops an infinite life cycle assessment model, which integrates LCA, substance flow analysis, and a state transition matrix into an infinite-life-cycle framework. On this basis, algorithms are formulated to quantify the resource efficiency and attribute environmental impacts following the principle of whole first, then allocation. Our model is demonstrated by a case study of lead-acid batteries. Results show that the resource efficiency of lead in the infinite life cycle assessment model is at least 118.75% higher than that of primary lead derived from the typical finite life cycle models. Measured by the index of environmental toxicity potential, environmental impacts are transferred from the primary product life cycle to recycled product life cycles, with the range fluctuating from 66.26% to 68.12%. Our model enables scholars to make more reasonable assessments for circular economy systems based on traditional LCA adjustment. From the infinite-life-cycle perspective, sustainable production policies should focus on increasing the recycling rate of waste products rather than limiting the exploitation of natural resources.
... The ever-growing demand for materials and energy resources has given rise to a significant build-up of natural resources in waste deposits. The accumulation of such massive quantities of industrial, metallurgical, and mining waste could result in the geological storage of a significant quantity of valuable resources such as metals, minerals, and energy or biomass [9][10][11][12]. It is paramount that such wastes are exploited for their valuable contents through cost-effective and eco-friendly means. ...
The rapid depletion of high-grade rare earth elements (REE) resources implies that future supplies may be augmented with low-grade ores, tailings, and other unconventional resources to meet cut-off grades and, subsequently, supply demands. This paper presents an amalgamation of studies conducted on selected complex low-grade iron-oxide-silicate-rich tailings, with the overall aim of developing efficacious methods and associated process mineralogy characterization for enhanced REE minerals recovery and upgrade. To this end, a summary of the overarching key results from froth flotation, magnetic separation, and gravity separation studies of the tailings and their implications are presented in this review. Reconciliation of all the findings reveals lucid links between feed ore properties, mainly mineralogy and particle size distribution, as the key influential factors that affect the beneficiation of real complex low-grade tailings, although distinct differences in physicochemical properties of the valuable and gangue minerals may exist. It is clearly established that the unliberated association between REE and gangue minerals within the ore can lead to either synergistic or antagonistic effects on the quality of concentrates produced. Furthermore, the limitations presented by the poorly liberated minerals are exacerbated by their “fine” nature. With appreciable recoveries obtained using such readily available conventional separation methods, the tailings provide additional REE value to the primary commodities; hence, such material could be considered a potential resource for REE beneficiation. The learnings from the respective beneficiation studies are significantly important as they provide the knowledge base and greater understanding of the mineralogical characteristics and beneficiation response of REE minerals in typical complex, low-grade tailings.
... Among them, Cu has accounted for 10-25% of the metal contents in e-waste, which was higher than the Cu content found in raw and virgin ores (Fogarasi et al., 2014;Jadhao et al., 2021;Khaliq et al., 2014). Hence, the paradigm shift onto the urban mining of Cu from e-waste could be more sustainable, pragmatic and cost-effective than conventional ore mining and processing (Zeng et al., 2018). Cu extraction from e-waste requires multi-stage processes in conventional pyrometallurgy or hydrometallurgy, followed by various downstream separation and recovery processes, including chemical precipitation, ion-exchange, adsorption, solvent extraction and electrowinning to recover Cu Li et al., 2018). ...
Smart technologies and digitalisation have increased the consumption of scarce metals that threaten the sustainability of intricated industries. Additionally, the growing streams of waste electrical and electronic equipment (e-waste) are significant hazards to public health and the environment. Thus, there is an escalating need to recover metals from e-waste for sustainable management of metal resources. Hydrometallurgical processing of e-waste, involving copper (Cu) leaching and its subsequent recovery from pregnant leach solution (PLS) via electrowinning, has emerged as an efficient strategy to close the recycling loop. Electrowinning from PLS demonstrated higher Cu recovery efficiency and operational feasibility with a lower reagent use and lesser waste generation. Nevertheless, multiple issues challenged its practical implementation, including selective recovery of Cu from PLS containing mixed metals and high energy consumption. This review (1) identifies the factors affecting Cu electrowinning from PLS; (2) evaluates the composition of lixiviants influencing Cu electrowinning; (3) appraises various catalysts developed for enhancing Cu electrodeposition; and (4) reviews coupled systems that minimised process energy consumption. From the literature review, electrocatalysts are prospective candidates for improving Cu electrowinning as they reduced the cathodic reduction overpotentials, enhanced surface reaction kinetics and increased current efficiency. Other catalysts, including bioelectrocatalysts and photoelectrocatalysts, are applicable for dilute electrolytes with further investigations required to validate their feasibility. The coupled systems, including slurry electrolysis, bioelectrochemical systems and coupled redox fuel cells, minimise process energy requirements by systematically coupling the cathodic reduction reaction with suitable anodic oxidation reactions having thermodynamically low overpotentials. Among these systems, slurry electrolysis utilising a single-step processing of e-waste is feasible for commericalisation though operational challenges must be addressed to improve its sustainability. The other systems require further studies to improve their scalability. It provides an important direction for energy-efficient Cu electrowinning from PLS, ultimately promoting a circular economy for the scarce metal resources.
... Landfill mining and urban mining involve the recovery of valuable resources from all kinds of deposits and anthropogenic stocks [6]. The concept of using biological, chemical, or mechanical techniques to recover valuable metals from waste electrical and electronic equipment has already proven to be more cost-effective than original mining [7]. Furthermore, an evaluation of the economic potential of landfill mining in Europe has shown that resource recovery can become net profitable [8]. ...
Decreasing ore grades and an increasing consumption of metals has led to a shortage of important primary raw materials. Therefore, the urban mining of different deposits and anthropo-genic stocks is of increasing interest. Basic oxygen furnace (BOF) slag is produced in huge quantities with the so-called Linz-Donawitz process and contains up to 5.2, 0.9, 0.1, and 0.07% of Mn, Al, Cr, and V, respectively. In the present study, sulfur-oxidizing Acidithiobacillus thiooxidans and iron-and sulfur-oxidizing Acidithiobacillus ferridurans were applied in batch and stirred tank experiments to investigate the biological extraction of metals from BOF slag. In the batch experiments, up to 96.6, 52.8, 41.6, and 29.3% of Cr, Al, Mn, and V, respectively, were recovered. The stirred tank experiments , with increasing slag concentrations from 10 to 75 g/L, resulted in higher extraction efficien-cies for A. ferridurans and lower acid consumption. Selective metal precipitation was performed at pH values ranging between 2.5 and 5.0 to study the recovery of Mn, Al, Cr, and V from the biolix-iviant. Selective precipitation of V and Cr was achieved at pH 4.0 from A. thiooxidans biolixiviant, while Fe and V could be selectively recovered from A. ferridurans biolixiviant at pH 3.0. This work revealed the potential of BOF slag as an artificial ore for urban mining and demonstrated that combining bioleaching and selective precipitation is an effective method for sustainable metal recovery.
... In many regions and countries, the retired mobile phones are classified as waste electrical and electronic equipment (WEEE), which is also named electronic waste, e-waste, or e-scrap (Amphalop et al. 2020;Andersen 2022;Andrade et al. 2019;Cai et al. 2020;Song et al. 2017;Yu et al. 2017a). The retired mobile phones are classified as a kind of typical small WEEE for the reasons such as small volume, huge amount, high reuse, and recovery value (Alghazo et al. 2019;Ambaye et al. 2020;Batoo et al. 2022;He et al. 2021b;Li et al. 2021;Sharma et al. 2020;Xie et al. 2021;Yuksekdag et al. 2022;Zeng et al. 2018;Zhu et al. 2022). ...
The generation estimation of retired mobile phones is launched with the sales and new method using the revised sales data and amount of the subscribers. Several assumptions have been made due to the insufficient sources of the data. The sales data of legal mobile phones are calculated with the authoritative and continuous official data. The sales data of smuggled and counterfeit mobile phones in China are also estimated based on the behavior data collected from the questionnaires. The results of generation estimation show that there are 636.52 million mobile phones retired in 2020, compared with 14.44 million in 1999 and several negative values in 2000, 2001, and 2008. The annual total mass of retired mobile phones in China escalated with the contributions of both the increasing generation amount and constant mass of the single unit. There are 50,921.60 ton of mobile phones retired in 2020 compared with 1155.20 ton in 1999, while the peak is 58,131.20 ton in 2019. There are 26,066.80 ton of retired mobile phones are stockpiled in 2020, while 16,152.40 ton and 8702.40 ton of retired mobile phones are reused as a whole unit and recycled, respectively. In the retired mobile phones that are recycled, 4600.50 ton material is recovered and 1216.50 ton components are reused, while 2885.40 ton residues need final disposal. The amount and dynamic characteristics of metals in the retired mobile phones are also calculated. Based on the results, several policy implications are made to improve sustainable management system of retired mobile phones in China.
... Currently, precious metals such as gold (Au), silver (Ag), platinum (Pt), and palladium (Pd) serve as raw materials for many high-tech industry applications, such as catalysts [1,2], electronic products [3], fuel cells [4], and medicine [5], because of their unique physical and chemical properties. The limited availability and high economic value of precious metals have prompted the exploration of the recovery of those metals from secondary sources. ...
This paper presents an up-to-date overview of the various advanced materials as adsorbent used in the recovery of precious metals from wastewater. The precious metals concentrated here include gold, silver, palladium and platinum, whose recovery is interesting mainly due to their vast industrial applications and high market prices. Among various methods, adsorption approach is one of the most efficient techniques for the recovery of precious metal ions from aqueous solutions. There are a number of absorbents such as carbon materials, metal-organic frameworks (MOFs), biopolymers, silicas, resins, and transition-metal sulfides, which have been developed and explored to efficient recovery of precious metal ions from wastewater. Thermodynamics and kinetics were further discussed for exploring the adsorption mechanism of precious metal ions in these advanced materials. It was found that the adsorption process of these metals is mostly spontaneous (ΔG < 0) and endothermic (ΔH > 0) in nature. This review would contribute to the development of advanced materials for recovery of precious metals from secondary sources such as wastewater.
Graphical abstract
... An economic comparison between the recovery option and virgin production is also discussed outlining the efficacy of the proposed recovery process. This tendency is also confirmed by Zeng et al. (2018): the authors proposed a quantitative analysis of the economic feasibility of extracting copper and gold from discharged TV sets in China. Results outline the economic convenience of the UM process compared to pure materials extraction and production. ...
The chapter examines the problem of e-waste movements among countries around the world, particularly from high-income economies with advanced waste management systems towards low and middle-income countries with serious public health and environmental repercussions. Despite the fact that the Basel Convention forbids certain hazardous waste streams to be exported into countries with poor waste management facilities, the environmental pollution associated with e-waste flow reaches alarming levels due to illegally or legally importing large amounts of waste continuing unbated. The chapter investigates the gaps in the e-waste management system which led to the transboundary movements of e-waste items supported by academic literature review. The chapter highlights the main challenges of e-waste exportation and importation issues in some major geographical areas such as Europe, Asia-Pacific, Africa, and North America and how unsound waste management practices feed a new “colonization” form in the twenty-first century. Best policies and practices are revealed to mitigate the illegal traffic of the e-waste flow or “ second hand” electronic goods towards poorer countries. The expansion of urban mining practices and the circular economy paradigm should reduce the global traffic of e-waste flows combined with the improvement of the Basel Convention content and the ratification process
For the conservation and sustainable utilization of metallic resources, recovering precious metals from the vast quantity of waste printed circuit boards is an attractive avenue. Bioleaching has been proved as an environment-friendly and suitable recovery technology. However, the limited cyanogenic capability restricts the industrialization of this technology. To break this bottleneck, in this paper, an innovative bioleaching technology assisted by milliampere-level direct current was developed to enhance cyanogenic capability. Experimental results indicated 10 mA current was the most beneficial for cyanide production. At 10 mA, the cyanide concentration reached 5.05 mg/L, 1.48 times that of without electric current. With the assistance of milliampere-level direct current, the total energy required for the reaction from glycine anion to cyanide was decreased by 101.81 kcal/mol. Meanwhile, the added direct current reduced the relative abundance of Pseudomonadaceae but enriched Enterobacteriaceae. Clusters of orthologous groups function classification revealed that some functions involved in cyanide production such as secondary metabolites biosynthesis, transport and catabolism were more powerful. This work proposes a novel approach to break the bottleneck of low cyanogenic capability in bioleaching technology, providing crucial scientific information for the industrialization of bioleaching.
For the first time, a polyethyleneimine-impregnated alginate capsule (PEIIAC) with a high adsorption capacity is developed for the recovery of monovalent and trivalent gold from an acidic solution. The strategy results in a new type of adsorbent, polyethyleneimine impregnated alginate capsule (PEIIAC) with a core–shell structure having a large number of amine groups as cationic binding site, facilitating maximum uptake of anionic auric chloride. The maximum uptake of PEIIAC was 3078 and 929 mg/g for Au (III) and Au (I), respectively, are recordable compared to other reported adsorbents to date. The as-prepared material was executed to check the sorption efficacy for Au (III) and Au (I) in the pH range of 1–12. With an increment in pH, the uptake capacity for Au (III) increased, while the uptake capacity for Au (I) decreased. The FTIR, XRD, and XPS studies revealed that the gold adsorption mechanism includes ionic interactions and reduction, wherein the amine, hydroxyl, and carboxyl groups are involved. The capsule showed a higher adsorption efficiency than other reported sorbents, making the material applicable in acidic solutions for the recovery of Au (I) and Au (III).
Recycling of waste electrical and electronic equipment (WEEE) is attracting increasing attention, due to the presence of valuable metals and the risk of environmental emissions associated with WEEE disposal. In this study, the distributions of trace elements (Ag, Ni, Co, and Sn) between copper alloy and magnetite/wüstite-saturated
iron silicate slags were investigated at 1200–1300 ◦C and PO2 of 10-10-10-6.5 atm, simulating the conditions of WEEE reprocessing through secondary copper smelting and converting. The high temperature isothermal equilibration experiments were conducted in synthesized magnetite/wüstite crucibles under controlled CO-CO2
atmospheres followed by quenching in an ice-water mixture. The phase compositions and concentrations of the trace elements in copper alloy, magnetite/wüstite, and slag were determined by Electron Probe X-ray Microanalysis and Laser Ablation-High-Resolution Inductively Coupled Plasma-Mass Spectrometry. The distribution
coefficients of all investigated trace elements between copper alloy and slag increased with decreasing oxygen partial pressure and increasing temperature. Ag distributed strongly into the copper alloy at all conditions, whereas Co mainly deported into the slag phase. Ni and Sn were concentrated in the alloy at lower PO2 and in the slag at higher PO2. Varying concentrations of Ni, Co, and Sn were also dissolved into the solid magnetite/wüstite phase.
Depolymerization of polyethylene (PE) is one of the most challenging tasks in the chemical upcycling of PE-based plastic wastes because the disassociation of the stable carbon-carbon bonds in PE is only possible at a very high reaction temperature. The thermal liquefaction of PE cable plastic waste in a stainless-steel batch reactor was thoroughly evaluated in this study. The effect of different liquefaction methods (hydrothermal liquefaction (HTL), ionic liquids catalyzed HTL, and solvothermal liquefaction (STL)) on the yields of product fractions (oil products, solid residue, and gas) and the properties of the oil products were examined. At 350 °C and 90 min reaction duration, the conversion (%) of 75.43%, the oil yield of 39.33%, the energy recovery rate of 39.7%, the higher heating values (HHV) of 43.83 MJ/kg for the oil samples, and the lower boiling range molecular distribution were obtained by the solvothermal liquefaction method with acetone as a solvent. The HHV of the oil samples obtained in the STL method (43.28-43.83 MJ/kg) is comparable to that of gasoline (HHV - 43.4 MJ/kg). The contribution of the solvent to the depolymerization reaction was mainly the dissolution and dispersion of feedstock by solvation, therefore reducing thermal cracking temperature through enhanced mass and thermal energy transfer. In thermal liquefaction, solvent and feedstock had a low level of solvolysis reactions, so the depolymerization reaction mainly follows thermal cracking. The main reaction path is the random scission of PE molecules during heat treatment, with a low level of polymerization, cyclization, and radical recombination reactions, which occurred through the free radical mechanisms. This work has demonstrated the feasibility of a very promising technique for effective chemical upcycling of polyethylene-based plastics.
Precious metal recovery from electronic waste, termed urban mining, is important for a circular economy. Present methods for urban mining, mainly smelting and leaching, suffer from lengthy purification processes and negative environmental impacts. Here, a solvent-free and sustainable process by flash Joule heating is disclosed to recover precious metals and remove hazardous heavy metals in electronic waste within one second. The sample temperature ramps to ~3400 K in milliseconds by the ultrafast electrical thermal process. Such a high temperature enables the evaporative separation of precious metals from the supporting matrices, with the recovery yields >80% for Rh, Pd, Ag, and >60% for Au. The heavy metals in electronic waste, some of which are highly toxic including Cr, As, Cd, Hg, and Pb, are also removed, leaving a final waste with minimal metal content, acceptable even for agriculture soil levels. Urban mining by flash Joule heating would be 80× to 500× less energy consumptive than using traditional smelting furnaces for metal-component recovery and more environmentally friendly.
Resources are essential for human survival and development, and resource security occupies an important position in national security. With the increasing resource shortage problem, ecological stability is facing severe challenges. All countries are actively seeking new sustainable development ways to deal with various issues and shocks caused by the shortage of resources. This study aims to systematically and comprehensively evaluate the knowledge structure, research hotspots, and resource security evolution trends. Based on the number of 6391 articles retrieved from the Web of Science database from 1990 to 2021, this article carried out a visual analysis of global resource security research from the perspectives of scientific output characteristics, keywords, and highly cited literature scientific collaboration networks and hotspot emergence analysis. The research results show that after humans have experienced new public safety incidents, their understanding of resource security and sustainable development has risen to a new height. The number of relevant documents is increasing rapidly. At present, the research on resource security is still dominated by developed countries in Europe and America. This study finds that “food supply chain,” “water availability,” and “soil resources suitability” are the frontiers and hotspots in the field of resource security. Besides, “biodiversity,” “mineral resource security,” “medical and health resources” are important topics and directions of current research. This study provides a theoretical basis for scholars to explore the future research direction and practice of resource security, to achieve ecological stability and sustainable development.
The greening of business is now widely recognized as firms take the lead from reluctant governments in making sustainable operations profitable. The greening of business may be contrasted with the “business of greening” – in the sense that greening may be associated with the emergence of smart green platforms that propagate and expand as they creatively destroy industries that are rooted in a fossil fuelled past. Such considerations bring into focus the evolutionary economic dynamics of greening, involving business concepts like emergence of platforms and networks, the capture of increasing returns, the role of manufacturing, mass production and learning curves, which help to account for green innovation and green growth as drivers of the global green shift. This is a perspective that is distinguished from “zero growth” and “natural capitalism” approaches to greening; and it is one that is as applicable as much to China and emerging industrial powers as to advanced industrial countries. Fundamentally, greening is characterized as the emergence of green business platforms which create new possibilities for green growth as they propagate, driven by supply-side dynamics as much as by demand-side dynamics involving changed consumer behavior, as in the rise of the sharing economy. Fundamentally it is cost reduction (via learning curves) and capture of increasing returns that open up opportunities for new business strategies that creatively destroy the old business models associated with fossil fuels and resource wastage.
Gold is one of the most fascinating resources in the waste mobile phones’ printed circuit boards (WMPPCBs). In this study, a new process for recovering Au from WMPPCBs by the Na2S2O8-KI system was developed. This process comprises a two-stage leaching process to provide a separation of copper and gold from WMPPCBs. 98% Cu and 78% Fe were dissolved by the 1st base metals' leaching (H2SO4-H2O2 leaching) step. The leaching of gold from the solid reside of 2nd leaching step was performed to study the effect of Na2S2O8 concentration, KI concentration, temperature, and solid-liquid ratio in Na2S2O8-KI leaching system. The results showed that removing most of Cu greatly promoted the leaching efficiency of gold in Na2S2O8-KI leaching system. The mechanism of gold leaching was studied by the thermodynamic analysis. Leaching kinetics data showed that gold leaching followed an intermediate-controlled mechanism with Ea, 30.3 kJ mol⁻¹. The best conditions for leaching of gold in Na2S2O8-KI system were determined to be 0.02 M Na2S2O8, 0.15 M KI, 40℃, a solid-liquid ratio of 1: 20 (g/mL), and a stirring speed of 200 rpm. Under the optimal leaching parameters, the efficiency of gold leaching from WMPPCBs attained 96% after 120 min. Due to the non-toxic and low-cost properties of Na2S2O8, the Na2S2O8-KI leaching process is more sustainable than conventional processes (cyanide leaching et al.).
With the rapid development of China's automobile industry, the surge in the number of end-of-life vehicles (ELVs) has put great pressure on the environment. On the other hand, ELVs contain multiple recyclable metal resources and can be regarded as an important source of urban mining. In order to explore the potential of secondary resources supplies from urban mines in the automotive industry, considering different policy conditions, this study not only forecasts China's recyclable metal resources from 2021 to 2030 at the national level, but also introduces two indicators of area and population, focusing on the differences in provincial distribution. Combined with the characteristics of each province, the gap between future demand for vehicle scrap recycling and the current status of China's ELV management is analyzed. The results show that although the extension of vehicle service life in the future will effectively reduce the number of ELVs, there will be an obvious imbalance of ELV between provinces by 2030 due to the different development conditions of provinces. In the future, considering the insufficient landfills and high disposal costs in relatively developed areas, ELV recycling channels should be set up in multiple geographical locations within China, so that the pressure of controlling total domestic ELV recycling can be eased, as well as the governance of dismantling enterprises.
Electronic waste is an indirect and unimaginable waste which make adverse effects on the human, animals and environment by polluting the natural resources like air, soil and water. Accumulation and contamination of e-waste for a longer period may harshly affect the environmental resources. India and China are the largest consumers of electronic gadgets at the same time they are responsible for an increase in the waste electrical and electronic equipment. Therefore, this review article mainly focuses on the detailed explanation of the e-waste management system includes the recycling process and its effects in India. The uniqueness of this review article lies in the discussion of legal instruments and awareness programs in India at various periods of time. Also, it provides sufficient knowledge to the readers in various aspects of increasing e-waste and its controlling methods. As a result, it gives adequate information for reducing the utilization of e-product in consumer-side and control measures on the manufacturer-side. In addition to that, it will be helpful to the policymakers who are involving in framing the future policy of e-waste in India.
As a renewable energy source, hydrogen production from biomass pyrolysis is one of the effective ways to promote global sustainable development. Herein, the inherent Al foils and typical LiCoO2 cathodes in spent lithium ion batteries are jointly employed as the catalyst to reform sawdust pyrolysis gas to produce hydrogen-rich synthesis gas. It is the introduction of Al element that triggers the in-situ atomic replacement reaction to immobilize volatile lithium, thereby inducing the formation of a similar Li-CO2 battery system, which efficiently converts CO2 into CO. Furthermore, a new adsorption-enhanced in-situ-assembled porous structure has been discovered and proved to obtain ~95% surface vacancy oxygen content and various hydrogen evolution sites. Eventually, the yields and volume fractions of H2 are 11.31 mmol/g and 65.79%, respectively, and the purity of syngas (H2+CO) reaches 91.82%, which verify its excellent performance in hydrogen reforming and CO2 conversion.
Alternative mining methods are becoming increasingly important towards sustainable and eco-friendly gold (Au) production. Herein, thiacrown ether (diallyl 15TCE4) with Au³⁺ recognition properties was combined with thermo-responsive N‑isopropylacrylamide (NIPAM) on a silica (SiO2) support via ARGET-ATRP to afford a multi-functional Au³⁺ adsorbent P(NIPAM-co-15TCE4)@SiO2. The adsorbent was successfully prepared as confirmed by FTIR, NMR, TGA, EA, FE-SEM and DLS. The thermo-responsiveness of P(NIPAM-co-15TCE4)@SiO2 was observed at critical temperature Tc ∼34.9 oC. At T = 50 oC (T > Tc) and pH = 2, the maximum Au³⁺ capacity qm = 100.60 mg g⁻¹ was quickly achieved within 2 h. HR-TEM/EDS, WAXD and XPS results indicate that Au³⁺ capture involves complexation, partial reduction to Au⁺ and disproportionation to Au⁰/Au³⁺. It is believed that partial Au³⁺ reduction is coupled with C-S-C oxidation to R2S=O in 15TCE4, which occurred within its cavity and/or between neighboring 15TCE4s that are closely held by the collapsed NIPAM at T > Tc. Meanwhile, desorption occurs at T < Tc through “mechano”-assisted Au release induced by the brush network movement as NIPAM component rehydrates at T = 27 oC. Complete desorption was achieved even in a very mild lixiviant (0.1M HCl/0.1M TU) that eluted tightly-bound Au species and regenerated the adsorbent via S=O reduction to C-S-C. The adsorbent is highly selective with α = 9 – 43,053 for Au³⁺ against Pd²⁺, Pt²⁺, Cu²⁺, Pb²⁺, Zn²⁺ and Ni²⁺ present in a simulated mobile phone leachate. The reversible behavior of P(NIPAM-co-15TCE4)@SiO2 for Au³⁺ capture (T > Tc) and release (T < Tc) highlights the synergy between 15TCE4 and NIPAM, making it a reusable practical adsorbent with consistent performance for Au³⁺ recovery in complex feed wastes.
The extraction of metals from e-waste is currently not well understood. In this regard, a promising method for the extraction of metals was chosen, namely the biotechnological method. E-waste includes various categories of waste. This complicates the search and development of a universal method for disposing of electronic waste. In this regard, one category of e-waste was selected, namely mobile phone screens. The article presents the results of experimental studies on assessing the efficiency of metal sorption from mobile phone screens by microscopic algae at various parameters of biosorption.
The present study evaluates the application of top-down steel demand estimation in developing countries. The anticipated steel demand for the case of Iran is calculated by three methods, including the growth model (GM), the intensity of use hypothesis (IUH), and the fixed stock paradigm (FCP). GM shows a broad range of apparent steel demand based on the assumed growth factor. When the gross domestic product (GDP) per capita reaches 13,000 dollars per person (constant 2010 US$), the IUH method estimates the consumption peak consumption at around 500 kg steel per capita per year, which is being expected between 2040 and 2060 depending on the economic growth assumptions. Since fluctuations in the developing countries minimally affect the FCP, the steel demand based on this model is used to study the potential to satisfying the demand for steel in transportation sector from the scrap generated in the same sector. Iran faces a deficit of almost 8 million tons of steel scrap per year by 2025. Thus, the current examines the potentiality of supplying the required steel demand from the transport sector in two economic scenarios, including “regional rivalry” with restricted economic development and “fossil-fueled development’’ which focuses on the highest economic development using the temporal distribution matrix (TDM) method. Both scenarios demonstrate that the steel consumption peak appears from 2030 to 2040. The maximum steel demand in the transportation sector is 25% lower in the regional rivalry scenario than the fossil-fueled development. Moreover, while this scenario provides a steady trend in steel production and consumption by 2050, the scrap of the transport sector may fulfill the demand for steel in this sector; comparatively, this trend happens with 20 years delay in the fossil-fueled development scenario.
Copper indium gallium diselenide (CIGS), is a promising commercial thin-film solar cell, and its disposal after scrapping and recycling critical metals has attracted tremendous attention since CIGS can be considered an important type of urban mining. The main phase of spent CIGS is selenide, which is a hazardous contaminant that may have a potential impact on the environment and human body. In our previous study, selenium and copper in spent CIGS separated efficiently, while more scarce metals: indium and gallium were obtained in the form of mixed indium gallium oxide (IGO). Therefore, in this study, the separation and purification of indium and gallium was investigated in detail. The solution chemical behavior shows that the dissolution of indium gallium oxide (IGO) in an alkaline environment was significantly different. Selective alkali leaching is feasible to separate indium and gallium effectively. The process realized 97.26% gallium leaching out, while that of indium was 3.37%. Moreover, the mechanism of the leaching process and the removal of copper impurities were explored, with further purification, indium and gallium were obtained in the form of relatively pure indium oxide (96.04%) and gallium oxide (99.83%), respectively. This study will provide guidance for the recycling of critical metals from secondary waste.
The recycling and treatment of plastic waste become an increasingly serious environmental degradation challenge. To promote the recycling of end-of-life vehicles (ELVs), it is essential to estimate the scale of total plastic materials. This paper mainly contributes to a long-term estimation of overall plastic materials from ELVs in China. It focused on the estimation of the plastic materials from ELVs up to year of 2030, and a scenario analysis considering the recycling rate standard and light-weighting technology was performed. The results show that the total ELVs in 2030 will reach 28.54 million, which is 2.7 times the total in 2020. Under the scenario with a high standard of recycling rate (over 90%) and an exponentially growing share of plastic contents in passenger cars, the total plastic materials may reach 4.88 mt (approximately 35.70–36.56 billion yuan) in 2030. The paper provides important insights to vehicle producers by suggesting deploying more plastic materials, especially the re-use of recycled plastics, in the design and production of new products; as well as to recycling policymakers by suggesting enhancing the regulation of vehicle recycling to ensure the potential supply of all recyclable materials from ELVs including plastics.
Urban mining is essential for continued natural resource extraction. The recovery of rare and precious metals (RPMs) from urban mines has attracted increasing attention from both academic and industrial sectors, because of the broad application and high price of RPMs, and their low content in natural ores. This study summarizes the distribution characteristics of various RPMs in urban mines, and the advantages and shortcomings of various technologies for RPM recovery from urban mines, including both conventional (pyrometallurgical, hydrometallurgical, and biometallurgical processing), and emerging (electrochemical, supercritical fluid, mechanochemical, and ionic liquids processing) technologies. Mechanical/physical technologies are commonly employed to separate RPMs from nonmetallic components in a pre-treatment process. A pyrometallurgical process is often used for RPM recovery, although the expensive equipment required has limited its use in small and medium-sized enterprises. Hydrometallurgical processing is effective and easy to operate, with high selectivity of target metals and high recovery efficiency of RPMs, compared to pyrometallurgy. Biometallurgy, though, has shown the most promise for leaching RPMs from urban mines, because of its low cost and environmental friendliness. Newly developed technologies—electrochemical, supercritical fluid, ionic liquid, and mechanochemical—have offered new choices and achieved some success in laboratory experiments, especially as efficient and environmentally friendly methods of recycling RPMs. With continuing advances in science and technology, more technologies will no doubt be developed in this field, and be able to contribute to the sustainability of RPM mining.
Human-made material stocks accumulating in buildings, infrastructure, and machinery play a crucial but underappreciated role in shaping the use of material and energy resources. Building, maintaining, and in particular operating in-use stocks of materials require raw materials and energy. Material stocks create long-term path-dependencies because of their longevity. Fostering a transition toward environmentally sustainable patterns of resource use requires a more complete understanding of stock-flow relations. Here we show that about half of all materials extracted globally by humans each year are used to build up or renew in-use stocks of materials. Based on a dynamic stock-flow model, we analyze stocks, inflows, and outflows of all materials and their relation to economic growth, energy use, and CO2 emissions from 1900 to 2010. Over this period, global material stocks increased 23-fold, reaching 792 Pg (±5%) in 2010. Despite efforts to improve recycling rates, continuous stock growth precludes closing material loops; recycling still only contributes 12% of inflows to stocks. Stocks are likely to continue to grow, driven by large infrastructure and building requirements in emerging economies. A convergence of material stocks at the level of industrial countries would lead to a fourfold increase in global stocks, and CO2 emissions exceeding climate change goals. Reducing expected future increases of material and energy demand and greenhouse gas emissions will require decoupling of services from the stocks and flows of materials through, for example, more intensive utilization of existing stocks, longer service lifetimes, and more efficient design.
The country consumes the most resources in the world and produces the most waste — but it also has the most advanced solutions, say John A.
Background:
Electronic waste (e-waste) is produced in staggering quantities, estimated globally to be 41.8 million tonnes in 2014. Informal e-waste recycling is a source of much-needed income in many low- to middle-income countries. However, its handling and disposal in underdeveloped countries is often unsafe and leads to contaminated environments. Rudimentary and uncontrolled processing methods often result in substantial harmful chemical exposures among vulnerable populations, including women and children. E-waste hazards have not yet received the attention they deserve in research and public health agendas.
Objectives:
We provide an overview of the scale and health risks. We review international efforts concerned with environmental hazards, especially affecting children, as a preface to presenting next steps in addressing health issues stemming from the global e-waste problem.
Discussion:
The e-waste problem has been building for decades. The increasingly observed adverse health effects from e-waste sites calls for protecting human health and the environment from e-waste contamination. Even if e-waste exposure intervention and prevention efforts are implemented, legacy contamination will remain, necessitating increased awareness of e-waste as a major environmental health threat.
Conclusion:
Global, national, and local levels efforts must aim to create safe recycling operations that consider broad security issues for people who rely on e-waste processing for survival. Paramount to these efforts is reducing pregnant women and children's e-waste exposures to mitigate harmful health effects. With human environmental health in mind, novel dismantling methods and remediation technologies, and intervention practices are needed to protect communities.
In-use stock of a product is the amount of the product in active use. In-use product stocks provide various functions or services on which we rely in our daily work and lives, and the concept of in-use product stock for industrial ecologists is similar to the concept of net manufactured capital stock for economists. This study estimates historical physical in-use stocks of 91 products and 9 product groups and uses monetary data on net capital stocks of 56 products to either approximate or compare with in-use stocks of the corresponding products in the United States. Findings include the following: (i) The development of new products and the buildup of their in-use stocks result in the increase in variety of in-use product stocks and of manufactured capital; (ii) substitution among products providing similar or identical functions reflects the improvement in quality of in-use product stocks and of manufactured capital; and (iii) the historical evolution of stocks of the 156 products or product groups in absolute, per capita, or per-household terms shows that stocks of most products have reached or are approaching an upper limit. Because the buildup, renewal, renovation, maintenance, and operation of in-use product stocks drive the anthropogenic cycles of materials that are used to produce products and that originate from natural capital, the determination of in-use product stocks together with modeling of anthropogenic material cycles provides an analytic perspective on the material linkage between manufactured capital and natural capital.
Unique environmental and economic challenges provide a laboratory for developing new indicator systems.
The useful life of electrical and electronic equipment (EEE) has been shortened as a consequence of the advancement in technology and change in consumer patterns. This has resulted in the generation of large quantities of electronic waste (e-waste) that needs to be managed. The handling of e-waste including combustion in incinerators, disposing in landfill or exporting overseas is no longer permitted due to environmental pollution and global legislations. Additionally, the presence of precious metals (PMs) makes e-waste recycling attractive economically. In this paper, current metallurgical processes for the extraction of metals from e-waste, including existing industrial routes, are reviewed. In the first part of this paper, the definition, composition and classifications of e-wastes are described. In the second part, separation of metals from e-waste using mechanical processing, hydrometallurgical and pyrometallurgical routes are critically analyzed. Pyrometallurgical routes are comparatively economical and eco-efficient if the hazardous emissions are controlled. Currently, pyrometallurgical routes are used initially for the segregation and upgrading of PMs (gold and silver) into base metals (BMs) (copper, lead and nickel) and followed by hydrometallurgical and electrometallurgical processing for the recovery of pure base and PMs. For the recycling of e-waste in Australia, challenges such as collection, transportation, liberation of metal fractions, and installation of integrated smelting and refining facilities are identified.
Achievement of sustainability in metal life cycles from mining of virgin ore to consumer and industrial devices to end-of-life products requires greatly increased recycling rates and improved processing of metals using conventional and green chemistry technologies. Electronic and other high-tech products containing precious, toxic, and specialty metals usually have short lifetimes and low recycling rates. Products containing these metals generally are incinerated, discarded as waste in landfills, or dismantled in informal recycling using crude and environmentally irresponsible procedures. Low recycling rates of metals coupled with increasing demand for high-tech products containing them necessitate increased mining with attendant environmental, health, energy, water, and carbon-footprint consequences. In this tutorial review, challenges to achieving metal sustainability, including projected use of urban mining, in present high-tech society are presented; health, environmental, and economic incentives for various government, industry, and public stakeholders to improve metal sustainability are discussed; a case for technical improvements, including use of molecular recognition, in selective metal separation technology, especially for metal recovery from dilute feed stocks is given; and global consequences of continuing on the present path are examined.
It is indisputable that modern life is enabled by the use of materials in its technologies. Those technologies do many things very well, largely because each material is used for purposes to which it is exquisitely fitted. The result over time has been a steady increase in product performance. We show that this materials complexity has markedly increased in the past half-century and that elemental life cycle analyses characterize rates of recycling and loss. A further concern is that of possible scarcity of some of the elements as their use increases. Should materials availability constraints occur, the use of substitute materials comes to mind. We studied substitution potential by generating a comprehensive summary of potential substitutes for 62 different metals in all their major uses and of the performance of the substitutes in those applications. As we show herein, for a dozen different metals, the potential substitutes for their major uses are either inadequate or appear not to exist at all. Further, for not 1 of the 62 metals are exemplary substitutes available for all major uses. This situation largely decouples materials substitution from price, thereby forcing material design changes to be primarily transformative rather than incremental. As wealth and population increase worldwide in the next few decades, scientists will be increasingly challenged to maintain and improve product utility by designing new and better materials, but doing so under potential constraints in resource availability.
Renewable energy requires infrastructures built with metals whose extraction requires more and more energy. More mining is unavoidable, but increased recycling, substitution and careful design of new high-tech devices will help meet the growing demand.
Facing significant natural resource consumption, environmental degradation, and resulting public frustration, China's new administration heightened attention on ecological modernization, green growth, and low carbon development, with a national circular economy (CE) strategy ( 1 ). The 2012 Rio+20 United Nations Conference on Sustainable Development emphasized the need to develop indicators of progress that decouple economic growth and environmental burden ( 2 ). We describe how China presents unique opportunities to develop new environmental indicator systems for measuring and managing CE.
Since the mid-1990s, electronic waste (e-waste) has been recognized as the fastest-growing component of the solid-waste stream,
as small consumer electronic products, such as cellular phones, have become ubiquitous in developed and developing countries
(1). In the absence of adequate recycling policies, the small size, short useful life-span, and high costs of recycling these
products mean they are routinely discarded without much concern for their adverse impacts on the environment and public health.
These impacts occur throughout the product life cycle, from acquisition of raw materials (2) to manufacturing to disposal at the end of products' useful life.
This exploratory paper sketches some of the behavioral processes that give rise to the learning curve. Using data from two manufacturing departments in an electronic equipment company, we construct a model of productivity improvement as a function of cumulative output and two managerial variables---engineering changes and workforce training. Exploration of this model highlights the complex relationship between first-order and second-order learning.
Reuse is always considered superior to materials and energy recovery in the waste hierarchy, a concept that also applies to Waste Electrical and Electronic Equipment (WEEE). In practice, however, reuse has not been a commonly used end-of-life option. We compared policies and practices of reuse of WEEE in China and in the EU. This comparison can help identify knowledge gaps and reuse policy requirements, as well as implementation methods We also discuss potential scientific solutions for reuse of WEEE via analysis of stakeholders' concerns. We found that although there are already reuse-related guidelines and standards in China, the policies need to be made more systematic like those of the EU, and they need to be more suitable for the specific challenges of China. We propose$ policy recommendations for reuse in order to facilitate sustainable management of WEEE, including integration of a reuse strategy into current management policy as well as the promotion of components reuse. Further, we also found that more studies on drivers and barriers to reuse are required to support more effective and efficient management.
In this article, current progress in urban mining related to e-waste recycling is reviewed and associated state-of-the-art recycling technologies are evaluated. As sufficient volume of e-waste is a limiting factor for its recycling economy, the need for the establishment of effective e-waste collection mechanisms, particularly for small sized End-of-Life (EoL) devices, is emphasized in terms of the need for effective government policies, increased public awareness, economic incentives, establishing industry-funded co-regulatory agreements, etc. Feasible options for e-waste recycling through pyro- and hydro-metallurgical process routes are reviewed. Deficiencies in e-waste recycling chains are highlighted, and recommendations to improve the current very low collection rate of small sized EoL devices such as mobile phones are made. Optimization of the recovery of the critical metals and energy through different processing options is discussed.
@ http://www.sciencedirect.com/science/article/pii/S0892687517301644
Successful delivery of the United Nations sustainable development goals and implementation of the Paris Agreement requires technologies that utilize a wide range of minerals in vast quantities. Metal recycling and technological change will contribute to sustaining supply, but mining must continue and grow for the foreseeable future to ensure that such minerals remain available to industry. New links are needed between existing institutional frameworks to oversee responsible sourcing of minerals, trajectories for mineral exploration, environmental practices, and consumer awareness of the effects of consumption. Here we present, through analysis of a comprehensive set of data and demand forecasts, an interdisciplinary perspective on how best to ensure ecologically viable continuity of global mineral supply over the coming decades.
International trade of discarded electronics (e-waste) has become a matter of concern over the last decade because of the actual and potential harms associated with their hazardous materials. An initiative under the aegis of the UN called the Best-of-Two-Worlds (Bo2W) philosophy is one solution to the e-waste problem that has gained some traction. Our dual purpose is to examine the ethical grounds of Bo2W and to propose an alternative program for action. We call this alternative ethical electronics repair, reuse, repurposing, and recycling (EER4). To explore the ethical grounds of Bo2W and to articulate EER4 as an alternative, we draw on notions of ethics, technology, and organization developed in science and technology studies (STS) and diverse economies literatures while empirically we explore a mixed methods case study of a small recycling firm in northern Mexico. Conceptually and empirically, our analysis points to a need for a richer imagination of the possibilities for economic action oriented toward managing discarded electronics. More broadly, our findings may act as a reminder that the space between use and discard proliferates the literal and figurative resources for enriching the imagination and enactment of diverse economic possibilities via the action of repair, reuse, repurposing, and recycling.
Aus der Perspektive des Metallrecyclings werden die Herausforderungen des nachhaltigen Stoffstrom-Managements im Kontext des aktuellen Kreislaufwirtschaftspakets der EU analysiert. Die Untersuchung der Recyclingtreiber zeigt die Schlüsselrolle der gesetzlichen Rahmenbedingungen für die Kreislaufschließung von Edel- und Sondermetallen in Konsumprodukten. Besondere Herausforderungen für ein effizientes und umweltgerechtes Recycling werden am Beispiel von Elektronikschrott herausgearbeitet. Hier ist die Etablierung von verpflichtenden Verfahrensstandards und Zertifizierungssystemen wichtig, um hohe Metallausbeuten im fairen Wettbewerb zu erzielen.
The derived waste from electrical and electronic equipment (WEEE, or e-waste) has become a global issue in the areas of environmental pollution, resource recycling, and sustainable industry. China is not only the largest producer and consumer of EEE, but also the country seriously polluted from illegal e-waste importation and informal recycling. In the past decade, China demonstrated a whole process of e-waste adventure: from serious pollution
in the start to regulation controlling in the present. Here, we specifically examine the past adventure of e-waste
management related to legislation system, and seek to outline the lessons and gaps. The proposed corresponding suggestions of policy could contribute to future China's e-waste management and provide a valuable reference for other countries and regions.
The management of waste electrical and electronic equipment (WEEE) is a well-stressed topic in the scientific literature. However, (i) the amount of cash flows potentially reachable, (ii) the future profitability trends and (iii) the reference mix of treated volumes guaranteeing a certain profitability level are not so clear, and related data are unrecoverable. The purpose of the paper is to fill in this gap by identifying the presence of profitability within the recovery process of waste printed circuit boards (WPCBs) embedded in WEEE. Net present value (NPV) and discounted payback time (DPBT) are used as reference indexes for the evaluation of investments. In addition, a sensitivity analysis of critical variables (plant saturation level, materials content, materials market prices, materials final purity level and WPCBs purchasing and opportunity costs) demonstrates the robustness of the results. Furthermore, the calculation of the national NPV for each of the twenty-eight European nations (in function of both WPCB mix and generated volumes) and the matching of predicted WPCB volumes (within the 2015–2030 period) and NPV quantify potential advantages. The break even point of gold allowing some profits from selected recovery plants goes from 73 to 93 ppm per WPCB ton, for mobile and field plants, respectively. Finally, the overall European values go from 2404 million € (mobile plant) to 4795 million € (field plant) in 2013, with Germany and United Kingdom as reference nations.
End of Life Vehicles (ELVs), together with Waste from Electric and Electronic Equipments (WEEEs), are re-known as an important source of secondary raw materials. Since many years, their recovery allowed the restoring of great amounts of metals for new cars’ production. However, the management of electronic systems embedded into ELVs is yet rarely considered by the scientific literature. The purpose of the paper is trying to fill in this gap through the proposition of an innovative economic model able to identify the presence of profitability within the recovery process of automotive Waste Printed Circuit Boards (WPCBs). Net Present Value (NPV) and Discounted Payback Time (DPBT) will be used to demonstrate the validity of investments in this type of plants. Furthermore, a sensitivity analysis on a set of critical variables (plant saturation level, gold (Au) content, Au market price, Au final purity level, WPCBs purchasing cost and opportunity cost) will be conducted for the evaluation of the impact of significant variations on results. Finally, the matching of predicted European ELVs volumes (during the period 2015-2030) and NPVs coming from the economic model will quantify the potential advantages coming from the implementation of this new kind of circular economy.
Demand for gold and silver has been escalating with increasing usage of electronic equipment globally. Around 267.3 MT of gold and 7275 MT of silver are being consumed annually for manufacturing mobile phones, laptops and other electronic equipment. However, only 15% is recuperated from these equipment; the remainder lies in the storage yards or landfills. The waste comprise glass, plastics, wires, batteries, PCBs, metal casing, etc. The PCB is composed of precious metals, which creates immense purpose for recycling and recovery. This paper characterises and assesses the recoverable metallic fraction of gold and silver from PCBs of mobile phones. The methodology is based on dismantling of the mobile handset and subjecting the PCBs to roasting and acid digestion. The digested samples were analysed by atomic absorption spectroscopy and the content of gold and silver in the PCBs was to be found in the range of 0.009–0.017% and 0.25–0.79% by weight respectively.
Increasing concerns on resource depletion and environmental pollution have largely obliged electrical and electronic waste (e-waste) should be tackled in an environmentally-sound manner. Recycling process development is regarded as the most effective and fundamental to solve the e-waste problem. Based on global achievements related to e-waste recycling in the past 15 years, we firstly propose the theory to design e-waste recycling process, including measuring e-waste recyclability and selection of recycling process. And we summarize the indicators and tools in term of resource dimension, environmental dimension, and economic dimension, to examine e-waste recycling process. Using the sophiscated experience and adequate information of e-waste management, spent lithium-ion batteries and waste printed circuit boards are chosen as case studies to implement and verify the proposed method. All the potential theory and obtained results in this work can contribute to future e-waste management towards best available techniques and best environmental practices.
The transport of discarded electronic and electrical appliances (e-waste) to developing regions has received considerable attention, but it is difficult to assess the significance of this issue without a quantitative understanding of the amounts involved. The main objective of this study is to track the global transport of e-wastes by compiling and constraining existing estimates of the amount of e-waste generated domestically in each country MGEN, exported from countries belonging to the Organization for Economic Cooperation and Development (OECD) MEXP, and imported in countries outside of the OECD MIMP. Reference year is 2005 and all estimates are given with an uncertainty range. Estimates of MGEN obtained by apportioning a global total of ∼35,000 kt (range 20,000-50,000 kt) based on a nation's gross domestic product agree well with independent estimates of MGEN for individual countries. Import estimates MIMP to the countries believed to be the major recipients of e-waste exports from the OECD globally (China, India, and five West African countries) suggests that ∼5,000 kt (3,600 kt-7,300 kt) may have been imported annually to these non-OECD countries alone, which represents ∼23% (17%-34%) of the amounts of e-waste generated domestically within the OECD. MEXP for each OECD country is then estimated by applying this fraction of 23% to its MGEN. By allocating each country's MGEN, MIMP, MEXP and MNET = MGEN + MIMP - MEXP, we can map the global generation and flows of e-waste from OECD to non-OECD countries. While significant uncertainties remain, we note that estimated import into seven non-OECD countries alone are often at the higher end of estimates of exports from OECD countries.
Recycling cannot meet the demand for rare metals used in digital and green technologies, says Andrew Bloodworth. A more holistic approach is needed.
High gold prices are making it worthwhile to look for gold in some
unusual places.
Metals are infinitely recyclable in principle, but in practice, recycling is often inefficient or essentially nonexistent
because of limits imposed by social behavior, product design, recycling technologies, and the thermodynamics of separation.
We review these topics, distinguishing among common, specialty, and precious metals. The most beneficial actions that could
improve recycling rates are increased collection rates of discarded products, improved design for recycling, and the enhanced
deployment of modern recycling methodology. As a global society, we are currently far away from a closed-loop material system.
Much improvement is possible, but limitations of many kinds—not all of them technological—will preclude complete closure of
the materials cycle.
Decisions involve many intangibles that need to be traded off. To do that, they have to be measured along side tangibles whose measurements must also be evaluated as to, how well, they serve the objectives of the decision maker. The Analytic Hierarchy Process (AHP) is a theory of measurement through pairwise comparisons and relies on the judgements of experts to derive priority scales. It is these scales that measure intangibles in relative terms. The comparisons are made using a scale of absolute judgements that represents, how much more, one element dominates another with respect to a given attribute. The judgements may be inconsistent, and how to measure inconsistency and improve the judgements, when possible to obtain better consistency is a concern of the AHP. The derived priority scales are synthesised by multiplying them by the priority of their parent nodes and adding for all such nodes. An illustration is included.. He is internationally recognised for his decision-making process, the Analytic Hierarchy Process (AHP) and its generalisation to network decisions, the Analytic Network Process (ANP). He won the Gold Medal from the International Society for Multicriteria Decision Making for his contributions to this field. His work is in decision making, planning, conflict resolution and in neural synthesis.
The use of the learning curve has been receiving increasing attention in recent years. Much of this increase has been due to learning curve applications other than in the traditional learning curve areas. A comprehensive survey of developments in the learning curve area has never been published. The closest thing to a survey was by Asher in 1956. His study focused exclusively on military applications during and immediately after World War II. This paper summarizes the learning curve literature from World War II to the present, emphasizing developments since the study by Asher. Particular emphasis is given to identifying the new directions into which the learning curve has made recent inroads and identifying fruitful areas for future research.
The increasing growth in generation of electronic waste (e-waste) motivates a variety of waste reduction research. Printed circuit boards (PCBs) are an important sub-set of the overall e-waste stream due to the high value of the materials contained within them and potential toxicity. This work explores several environmental and economic metrics for prioritizing the recovery of materials from end-of-life PCBs. A weighted sum model is used to investigate the trade-offs among economic value, energy saving potentials, and eco-toxicity. Results show that given equal weights for these three sustainability criteria gold has the highest recovery priority, followed by copper, palladium, aluminum, tin, lead, platinum, nickel, zinc, and silver. However, recovery priority will change significantly due to variation in the composition of PCBs, choice of ranking metrics, and weighting factors when scoring multiple metrics. These results can be used by waste management decision-makers to quantify the value and environmental savings potential for recycling technology development and infrastructure. They can also be extended by policy-makers to inform possible penalties for land-filling PCBs or exporting to the informal recycling sector. The importance of weighting factors when examining recovery trade-offs, particularly for policies regarding PCB collection and recycling are explored further.
The digital revolution affects the environment on several levels. Most directly, information and communications technology (ICT) has environmental impacts through the manufacturing, operation and disposal of devices and network equipment, but it also provides ways to mitigate energy use, for example through smart buildings and teleworking. At a broader system level, ICTs influence economic growth and bring about technological and societal change. Managing the direct impacts of ICTs is more complex than just producing efficient devices, owing to the energetically expensive manufacturing process, and the increasing proliferation of devices needs to be taken into account.
We have assembled extensive information on the cycles of seven industrial metals in 49 countries, territories, or groups of countries, drawn from a database of some 200,000 material flows, and have devised analytical approaches to treat the suite of metals as composing an approach to a national "materials metabolism." We demonstrate that in some of the more developed countries, per capita metal use is more than 10 times the global average. Additionally, countries that use more than the per capita world average of any metal do so for all metals, and vice versa, and countries that are above global average rates of use are very likely to be above global average rates at all stages of metal life cycles from fabrication onward. We show that all countries are strongly dependent on international trade to supply the spectrum of nonrenewable resources that modern technology requires, regardless of their level of development. We also find that the rate of use of the spectrum of metals stock is highly correlated to per capita gross domestic product, as well as to the Human Development Index and the Global Competitiveness Innovation Index. The implication is that as wealth and technology increase in developing countries, strong demand will be created not for a few key resources, but across the entire spectrum of the industrial metals. Long-term metal demand can be estimated given gross domestic product projections; the results suggest overall metal flow into use in 2050 of 5-10 times today's level should supplies permit.
Human activity has become a significant geomorphic force in modern times, resulting in unprecedented movements of material around Earth. An essential constituent of this material movement, the major industrial metals aluminium, copper, iron, and zinc in the human-built environment are mapped globally at 1-km nominal resolution for the year 2000 and compared with the locations of present-day in-ground resources. While the maps of in-ground resources generated essentially combine available databases, the mapping methodology of in-use stocks relies on the linear regression between gross domestic product and both in-use stock estimates and the Nighttime Lights of the World dataset. As the first global maps of in-use metal stocks, they reveal that a full 25% of the world's Fe, Al, Cu, and Zn in-use deposits are concentrated in three bands: (i) the Eastern seaboard from Washington, D.C. to Boston in the United States, (ii) England, Benelux into Germany and Northern Italy, and (iii) South Korea and Japan. This pattern is consistent across all metals investigated. In contrast, the global maps of primary metal resources reveal these deposits are more evenly distributed between the developed and developing worlds, with the distribution pattern differing depending on the metal. This analysis highlights the magnitude at which in-ground metal resources have been translocated to in-use stocks, largely from highly concentrated but globally dispersed in-ground deposits to more diffuse in-use stocks located primarily in developed urban regions.