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An assessment of metal supply sustainability as an input to policy: Security of supply extraction rates, stocks-in-use, recycling, and risk of scarcity
Abstract
The integrated model WORLD and Hubbert's model were used for assessment of future supply for different metals: iron, nickel, manganese, chromium, molybdenum, tantalum, niobium, rhenium, zirconium, tungsten, cobalt, copper, zinc, lead, aluminium and the technology metals derived from copper–zinc mining (tellurium, selenium, gallium, indium, antimony, bismuth, tin, germanium, selenium). The connections between their productions were mapped. The literature was reviewed for best estimates of total recoverable amounts, and best estimates were made, considering extraction costs and extractability. Peak years were determined for all the metals studied. Most metals seem to reach peak production during the next 4 decades, suggesting a risk for shortages in the near future. When supplies from mines dwindle, measures such as recycling from society's stock, substitutions to other materials than metals when this is possible, and stopped dissipative uses, will become important mitigation tools, calling for reorganization of resource policies world-wide. Present resource policies at all levels (regional, national, international) are to a large degree inadequate and need thorough review. The relevance of the Hubbert's model as an assessment tool was done. It is useful for all metals taken from independent ore deposits, whereas the method appears to be less suited for extraction of dependent metals unless the curve is derived from the Hubbert's model applied on the parent source. In such times, strategic thinking and strategic leadership based in systems thinking will be required.
... Gallium (Ga) and germanium (Ge) are technologically essential elements listed in the European Union's list of critical raw materials (European Commission, 2020). Gallium is mostly used in gallium arsenide (GaAs) compound semiconductors, which have applications in mobile phones and optoelectrical devices, such as laser emitting diodes (LEDs), solar cells, and military and wireless systems (Moskalyk, 2003;Butcher and Brown, 2014;Filella and Rodríguez-Murillo, 2017;Sverdrup et al., 2017;USGS, 2022a;Zhang et al., 2022). Germanium is mostly used in electronics and solar applications (e.g., fiber-optic systems), infrared optics (with military uses such as thermal imaging devices), in polymerization catalysis, and medical and metallurgical applications (Moskalyk, 2004;Melcher and Buchholz, 2014;Filella and Rodríguez-Murillo, 2017;Sverdrup et al., 2017;USGS, 2022b;Zhang et al., 2022). ...
... Gallium is mostly used in gallium arsenide (GaAs) compound semiconductors, which have applications in mobile phones and optoelectrical devices, such as laser emitting diodes (LEDs), solar cells, and military and wireless systems (Moskalyk, 2003;Butcher and Brown, 2014;Filella and Rodríguez-Murillo, 2017;Sverdrup et al., 2017;USGS, 2022a;Zhang et al., 2022). Germanium is mostly used in electronics and solar applications (e.g., fiber-optic systems), infrared optics (with military uses such as thermal imaging devices), in polymerization catalysis, and medical and metallurgical applications (Moskalyk, 2004;Melcher and Buchholz, 2014;Filella and Rodríguez-Murillo, 2017;Sverdrup et al., 2017;USGS, 2022b;Zhang et al., 2022). ...
... Most Ga is produced as a by-product of processing bauxite and from Zn-processing residues (Sverdrup et al., 2017;USGS, 2022a). The available resources of Ge are primarily associated with Zn and complex Pb-Zn-Cu ores, but significant amounts of Ge are also produced from coal combustion products (Sverdrup et al., 2017;USGS, 2022b). ...
Metallurgical slags enriched in Ga (144-156 mg/kg) and Ge (285-441 mg/kg) were investigated as potential sources of these technologically critical elements. Conventional mineralogical techniques (SEM/EDS, EPMA) were coupled with automated mineralogy using a Tescan Integrated Mineral Analyzer (TIMA) to quantitatively determine the partitioning of Ga and Ge in the slags. Both elements are primarily bound in the slag glass (90.5-95.4% of Ga and 95.9-96.7% of Ge). Extraction experiments conducted in 0.5 M H 2 SO 4 , 1 M HNO 3 , and 1 M HCl were used to simulate the hydrometallurgical recovery in view of the potential recovery of Ga and Ge. The leaching of Ga and Ge (and other valuable metals: Zn, Pb) was investigated as a function of time (2-12 h), temperature (25 and 70 • C), and particle size (original granulated slag and ultrafine-milled slag). Compared to other treatments, the highest Ga and Ge extractability was found in 0.5 M H 2 SO 4. No significant effect of the particle size, temperature, and time was observed on the Ga and Ge leaching. The optimum conditions for the extraction were: sulfuric acid treatment, original granulated slag (to limit the additional cost of crushing/mill-ing), 25 • C, and at least 6 h of extraction. Despite the high extractabilities of Ga and Ge, more tests are needed to validate the economic feasibility of their full-scale recovery, especially due to the highly fluctuating prices of these elements on the global market.
... In recent decades, ultrathin thin-film Cu (In 1-x Ga x ) Se 2 solar cell technologies exhibit high conversion efficiencies for low manufacturing cost, low material usage, material flexibility, and stability over longterm usage Frontier, 2019;Powalla et al., 2018;Sverdrup et al., 2017). The various approaches have been taken to improve efficiencies, such as optimized MgF 2 to be used as an anti-reflective coating, optimized Ga concentration in the CIGS absorber material, optimized the absorber, window, and buffer layer thicknesses (Frontier, 2019;Powalla et al., 2018). ...
... A CIGS thickness ranging between 2 and 3 μm is enough to assure light absorption. (Powalla et al., 2018;Sverdrup et al., 2017). Lightweight and ultra-thin flexible solar cells are particularly attractive to solar researchers and industries as they allow less materials to be used and thus reduce production time and cost. ...
... Lightweight and ultra-thin flexible solar cells are particularly attractive to solar researchers and industries as they allow less materials to be used and thus reduce production time and cost. (Sverdrup et al., 2017;British Geological Survey, Risk list, n.d.;Friedlmeier, 2015;Schleussner et al., 2011;Edoff et al., 2011;. However, lowering the thickness of the absorber layer below the micrometer scale may reduce the light absorption and limit the performance of the cell. ...
We use Silvaco-TCAD tools to optimize ultrathin Cu (In1-xGax) Se2 solar cells with rear surface passivation. First of all, the single CIGS structure was performed and calibrated with the electrical and optical output of the experimental results. Based on the simulation and example results, considering the variety of carrier’s transport mechanism at the heterointerface CdS/CIGS shows a significant impact on cell performance. The proposed rear passivated ultrathin CIGS structure consists the following configuration: MgF2 (120 nm)/ZnO:Al (300 nm)/ZnO(100 nm)/CdS(50 nm)/CIGS(500 nm)/Al2O3/Ag/glass-substrate. The effect of the rear-passivated, absorber thickness (CIGS), and cell pitch on ultrathin CIGS cell performance is analyzed and studied under AM 1.5G, 1 sun illumination. This increases the model’s total implied photocurrent density from 21.1 to 29.1 mA/cm². The simulations show that the ultrathin CIGS cell efficiencies of up to 13% can be obtained. The results from these simulations are compared with the measured characteristics of the fabricated cell.
... Past studies have investigated supply chain risks and solutions at different levels and for different sectors and types of materials. Literature exists on geological scarcity (Achzet and Helbig, 2013;Henckens et al., 2016;Sverdrup et al., 2017), material criticality (Erdmann and Graedel, 2011;Graedel and Reck, 2016;Jin et al., 2016;Schrijvers et al., 2020;Sonnemann et al., 2015), price (Leader et al., 2019), environmental impacts of production (Lee and Wen, 2017;Nuss and Eckelman, 2014;Weng et al., 2016;Zaimes et al., 2015), and geopolitical risks (E. D. Gemechu et al., 2015;Helbig et al., 2016). ...
... Supply risks relate to the physical availability of a material according to both available resources and ability to obtain the material from those resources. Metrics such as reserves (Sonderegger et al., 2017), ore grade (Sverdrup et al., 2017), depletion index (Goe and Gaustad, 2014) and byproduct production (Nassar et al., 2016) are shown by literature to be factors in supply risk. Data described in this section were obtained from the USGS (U.S. Geological Survey, 2020) and from published literature and are summarized in the SI Table S2. ...
... • Ore concentration (OC) is estimated as the mass percentage of material content in its typical ore deposits, where lower concentrations reflect scarcer and/or dispersed materials that require more energy or cost to extract. Data were compiled from literature (Sverdrup et al. (2017) for all elements except REEs. In the case of REEs, data compiled by Vahidi et al. (2016) based on (Schüler et al., 2011) for the Bayan Obo mine in China were used. ...
Electronic products are an essential part of modern society, but their importance has perhaps never been as palpable as when the COVID-19 pandemic forced almost every aspect of human interaction to go online. However, the pandemic also revealed that the supply chains that provide crucial raw materials for manufacturing electronics are increasingly vulnerable to social, geopolitical, and technical disruptions. These vulnerabilities are likely to escalate in the future, due to global health crises, natural disasters, and global political instability, all of which will be magnified by looming climate change impacts. This study investigates potential supply chain disruption risks in the electronics sector by applying metrics that capture supply, demand, socio-political, and environmental risks in a multi-criteria framework to almost 40 metals and minerals that provide critical functionality to electronic products. Results illustrate that the material risks varied with the potential nature of the disruption. For example, in scenarios where disruptions led to price volatility or weakening of environmental regulations, highest risks were observed for precious metals such as gold, rhodium, platinum, and palladium. On the other hand, in scenarios where disruptions led to supply pressures or geopolitical tensions, cobalt, gallium, and key rare earth elements exhibited the highest risks. These metals are characterized by energy-intense manufacturing and highly concentrated geographic production, suggesting that recycling and supply chain diversification may alleviate some of the identified risks. The analysis also considers trade-offs that may occur across social, economic, and environmental dimensions. For example, cobalt, a critical component in lithium-ion batteries, has significant social impacts due to production concentration in the Democratic Republic of the Congo. Shifting production to other regions may alleviate these risks but introduce new concerns about economic and environmental impacts.
... Indium has been a recent target for sustainability due to its physical scarcity, high cost, and widespread use in growing applications of transparent electrodes, which are also in demand for photovoltaic panels and high efficiency windows (Hun et al., 2018). The average concentration of cobalt (0.14%) and indium (0.001%) in e-waste in 2018 is still lower than observed ore concentration (Sverdrup, Ragnarsdottir, & Koca, 2017) (5% and 0.005%, respectively, at the high end), but specific products contain these materials to a greater degree, particularly smartphones and tablets ( Figures S5 and S7 in the Supporting Information). These materials are potential future priorities for recycling, particularly to create domestic supply chains, as geographical concentration and fluctuating global commodity value of these metals may lead to economic uncertainty in the electronics industry. ...
... Gold content in the U.S. e-waste stream (0.005% in 2018, Figure 4) remains over ten times higher than its estimated ore concentration (Sverdrup et al., 2017) (0.0003%). Historically, global e-waste recycling has relied on the economic value of gold, which is typically recovered through PCB smelting. ...
... Department of Energy, 2011), recovery from e-waste may present an opportunity for domestic mineral security or a buffer in commodity price volatility, underscoring the importance of policy instruments, recycling technologies, and infrastructure that can effectively reclaim these resources from end-of-life electronics. (Sverdrup et al., 2017). For most materials except Pd, Ag, and Au, e-waste concentration is lower compared to typical concentration in their respective ores. ...
Technological innovation has transformed the role of electronics in education, work, and society. However, rapid adoption and obsolescence of consumer electronics has also led to new concerns about resource consumption and waste management. Past research to address these sustainability challenges has been constrained by data that do not reflect nascent trends in product evolution and consumer adoption, thereby limiting the ability to create and assess proactive solutions. This study presents a dynamic analysis of electronic waste (e‐waste) in the United States using material flow analysis and highly resolved electronic product sales and material composition data. Findings contradict expectations that e‐waste is growing with mobile device proliferation, instead showing that the total mass of the e‐waste stream is actually declining (10% decrease since the estimated peak in 2015) with phase‐out of large, legacy products like cathode ray tube TVs. The evolving material profile of consumer electronics being purchased and disposed sees reduced risks of e‐waste toxicity from hazards like lead and mercury, but greater risks from reliance on scarce metals and product designs that limit recycling. This study highlights concerns that extended producer responsibility regulations currently implemented in many U.S. states for e‐waste management may become less effective if they continue to rely only on mass‐based collection targets. This article met the requirements for a gold‐gold JIE data openness badge described at http://jie.click/badges.
... In addition, using detailed and global scale mine data, several studies showed that primary production from natural ores could peak during the 21st century. Specifically, the estimated peak years (i.e., years when primary production peaks) are around 2041-91 for iron, 2084-2130 for aluminum, 2030-72 for copper, 2025-61 for zinc, 2018-2128 for lead, and 2030-33 for nickel (Ali et al., 2017;Calvo et al., 2017;Mohr et al., 2018;Northey et al., 2014;Sverdrup et al., 2017;H.U. 2015;Valero et al., 2018). ...
... Hubbert curve model (Calvo et al., 2017;Sverdrup et al., 2017Sverdrup et al., , 2015Valero et al., 2018) Scheduling model (Mohr et al., 2018(Mohr et al., , 2015Northey et al., 2014) System dynamics model (Sverdrup et al., 2017(Sverdrup et al., , 2015Vuuren et al., 1999) Linear programming model (Tokimatsu et al., 2017) Predator-prey model (Ali et al., 2017) T. Watari, et al. Resources, Conservation & Recycling 164 (2021) ...
... Hubbert curve model (Calvo et al., 2017;Sverdrup et al., 2017Sverdrup et al., , 2015Valero et al., 2018) Scheduling model (Mohr et al., 2018(Mohr et al., , 2015Northey et al., 2014) System dynamics model (Sverdrup et al., 2017(Sverdrup et al., , 2015Vuuren et al., 1999) Linear programming model (Tokimatsu et al., 2017) Predator-prey model (Ali et al., 2017) T. Watari, et al. Resources, Conservation & Recycling 164 (2021) ...
Sustainable metal supply requires well-coordinated strategy and policy packages based on a sound scientific understanding of anticipated long-term demand, supply, and associated environmental implications. Such information , however, is highly fragmented among various case studies. Accordingly, this extensive review explores the projected long-term status of six major metals-iron, aluminum, copper, zinc, lead, and nickel-with around 200 data points for global demand through 2030, 2050 and 2100. Our findings showed that global demand for these major metals is likely to increase continuously over the 21st century, increasing approximately 2-6-fold depending on the metal. Although the extraction and processing required to meet this increase in demand must be environmentally sustainable, the existing extraction and processing scenarios have few explicit linkages to the Earth's carrying capacity. We further found that strategy choices are heavily biased towards end-of-life phase analyses, specifically that of end-of-life recycling. Consequently, a full range of opportunities across entire life cycles is being overlooked, including advances in product design, manufacturing and in-use phases. Importantly, despite the emergence of numerous scenarios, few provide science-based targets for major metal flows, stock, circularity, and efficiency. These knowledge gaps need to be addressed urgently in order to ensure that future research directly supports science-based decision and policy making.
... Moreover, global demand for critical material resources has increased ten-fold since 1900 and is expected to double by 2030 Krausmann et al., 2009;Moss et al., 2011b). Keeping in mind this growing demand, Sverdrup et al. (2017) highlighted that many of the most critical materials for human society might be at risk of scarcity in the coming decades. Therefore, reliable and unconstrained access to critical raw materials is a growing concern within the world economy. ...
... This is, however, only a conditional part of what may constitute a solution (Graedel et al., 2011b). We need to look at sustainable recycling because past experiences demonstrate that efficiency gains are typically used to increase the overall quantity rather than save resources (Sverdrup et al., 2017). ...
... Given the rapid increase in primary and secondary niobium production over the last 15 years (Mackay and Simandl, 2014), the production rate will peak in 2025 with around 60% recycling rate (Sverdrup et al., 2017). A detailed review conducted by the United Nations Environmental Program estimated end-of-life recycling rate and recycling content of niobium to be more than 50% between 2000 and 2005 (Graedel et al., 2011b). ...
The world’s supply of critical materials such as phosphorus (P), niobium (Nb), lithium
(Li) and other strategically important elements is under increasing pressure due to the
rapidly growing global demand in the recent years and limited possibilities of
substitution. These materials are used in producing a broad range of products in everyday
life and forming an integral part of many advanced and clean energy technologies. Hence,
such materials are significant for many industrial sectors and essential to societal wellbeing.
Therefore, the steady supply of critical materials starts to be one of the key
economic and environmental questions. Moreover, the analysis of flows of those
materials coming from mining and recycling starts to evoke the growing interest.
A systematic understanding of how such materials flow through the industrial and
residential sectors is required. Such awareness of materials’ inclusion in various products
and their current stocks in the anthroposphere improve the potential of recycling and reuse
of those materials as well as minimize overall waste.
This dissertation presents dynamic models for critical materials such as P, Nb, and Li by
using system dynamicsmethodology. It considers all stages of supply chain by addressing
material and energy flows as well as greenhouse gas emissions. The main finding assists
in optimizing for environmentally sustainable operations in designing and modelling of
the critical materials supply chain.
The findings indicate a clear need to analyse the recycling processes carefully. The
obtained results show that recycling of used products containing critical materials, in
some cases, aims to prevent the shortage of those materials and contributes to developing
a robust circular economy. However, the environmental sustainability of recycling
procedures for all materials could not be taken for granted, because it could differ based
on the type of the waste stream. For some critical materials, recycling can cause more
environmental damage than mining. Therefore, we should not treat critical materials as a
homogeneous group. Recycling carried out using the existing technologies is a partial
solution for some materials. In addition, there are physical limitations to the increasing of
the recycling rate for some materials. The main limiting conditions of recycling can be
economic, environmental, and physical by nature. The lattermost means that even if
recycling is both more profitable and “greener” than mining, it is still impossible to
completely replace primary production with the secondary one.
... 2018;Thiébaud et al., 2018), the overall recycling efficiency of REEs has been estimated at about 1%. Junne et al. and Sverdrup et al. suggest that by 2050 recycling rates of 80% are achievable and reported recycling rates of 15% for REEs in 2017 (Junne et al., 2020), (Sverdrup et al., 2017). This further provides additional evidence that the recycling rates mentioned by Schulze and Buchert (Schulze and Buchert, 2016) are very optimistic. ...
... • Recycling yield is a product of collection, disassembly, and recovery efficiencies. • Recycling yield of 15% is obtained from literature and do not vary by product (Junne et al., 2020), (Sverdrup et al., 2017). • Magnets from one product are recycled to be used in same product (closed loop). ...
... Silver resources are mainly reported in countries such as Peru, Mexico, China, Poland and Chile [5]. Most of the production comes as a sub-product from refining copper, cadmium, and zinc [6]. Various rates of silver recycling can be found in literature between 30 % and up to 80 % [6]. ...
... Most of the production comes as a sub-product from refining copper, cadmium, and zinc [6]. Various rates of silver recycling can be found in literature between 30 % and up to 80 % [6]. The wide dispersion of sources, the recovery of the metal as a by-product from the extraction of lead-zinc, copper, gold, or copper-nickel deposits, and the increasing recycling make the supply risk not critical (6.2/10 according RSC, [5]). ...
Magnetic chitosan microparticles (MC) are successfully functionalized by grafting two pyrimidine derivatives (bearing either trione, MC-PYO, or trithione groups, MC-PYS). The sorbents are characterized using SEM, TEM, BET, TGA, FTIR, titration, and elemental analysis. The study focuses on the comparison of the differential effects of functionalized groups on the sorption of silver. FTIR analysis shows the contributions of N-based, carbonyl, hydroxyl for silver binding onto MC-PYO, completed by sulfur contribution in the case of MC-PYS. Maximum sorption capacities at pH 6 reach 1.9 and 2.3 mmol Ag g⁻¹ for MC-PYO and MC-PYS, respectively. The Langmuir and the Sips equations fit sorption isotherms. The reactive groups affect the thermodynamic characteristics: endothermic for MC-PYS against exothermic for MC-PYO. The affinity of S-based soft ligand in MC-PYS for soft metals makes the sorbent selective for Ag(I). On the opposite hand, for MC-PYO the O-based functional groups readily bind hard metals (HSAB principle), involving less selective for silver recovery (from multi-component solutions). QSAR method (quantitative structure-activity relationships) allows correlating preferentially sorption properties with the covalent index. Nitric acid solutions (0.3 M) are highly efficient for total desorption of silver from metal-loaded sorbents, but soft enough to maintain remarkable sorption and desorption performances for at least five cycles. The sorbents are successfully applied to Ag(I) recovery from acidic leachate of waste photographic films: metal removal is enhanced at pH 5.2; MC-PYS is more efficient and selective than MC-PYO at pH 2.2.
... This law of nature indicates the possibility of a path to be adopted for preservation, since productive processes belonging to a closed system, in which there is no exchange with the external environment, it can achieve sustainability by the transformation of residues in by-products to other industrial processes. Thus, it follows from the law of the conservation of mass that, in identifying the emission of pollutants or residues into the environment, countermeasures must be sought to ensure that the consumption of raw materials does not lead to to depletion; hence, the practices of recycling and reuse are recommended (Sverdrup, Ragnarsdottir, & Koca, 2017). ...
... Usiminas has developed a practical application for one of the residues of its ore transformation process; previously, this residue was discarded as solid residue. The new destination for the material by Usiminas is in line with the approach outlined by Sverdrup et al. (2017), according to which companies must establish recycling and reuse practices in order to mitigate the environmental impacts resulting from their activities. The innovation process developed by Usiminas incorporates the mitigation of social and environmental problems, as proposed by Barbieri et al. (2010). ...
The economic activity of the industry generates benefits, such as economic growth, and harm, such as waste discarded in the environment. The possibility of mitigating the harms of industrial activity, through sustainable innovations, is positioned as a topic of interest to society. In this context, this research analyzes the scope of socioenvironmental innovations that the Brazilian steel industry implements to mitigate the generation of solid waste. This research was based on a case study at Usiminas, one of the largest steelmakers in South America, using document analysis techniques and interviews with company representatives. The data indicate that through the performance of a multidisciplinary group the company developed four products that use the slag from the oxygen steelmaking as input. Although the product is patented, and its value is negotiated, the business model adopted was designed to contribute to the county. As a counterpart, the municipal beneficiary develops projects to protect water sources. In this way, technological innovations can transform the residue of the industry's processes into products that benefit the environment and society. Resumo A atividade econômica da indústria gera benefícios, como crescimento econômico, e malefícios, como resíduos descartados no meio ambiente. A possibilidade de mitigar os malefícios da atividade industrial, por meio de inovações sustentáveis, posiciona-se como tema de interesse para a sociedade. Neste contexto, esta pesquisa analisa o escopo das inovações socioambientais que a siderurgia brasileira implementa para mitigar a geração de resíduos sólidos. O desenvolvimento da pesquisa foi baseado em um estudo de caso na Usiminas, uma das maiores siderúrgicas da América do Sul, utilizando técnicas de análise de documentos e entrevistas com representantes da empresa. Os dados indicam que, por meio de um grupo multidisciplinar, a empresa desenvolveu quatro produtos que utilizam a escória da produção de aço com oxigênio como insumo. Embora o produto seja patenteado e seu valor seja negociado, o modelo de negócios adotado foi projetado para contribuir com o município. Como contrapartida, o beneficiário municipal desenvolve projetos para proteger as fontes de água. Dessa forma, as inovações tecnológicas podem transformar o resíduo dos processos da indústria em produtos que beneficiam o meio ambiente e a sociedade. Palavras-chave: Sustentabilidade, Acidente ambiental em Mariana, Educação ambiental, Inovação social e ambiental
... This law of nature indicates the possibility of a path to be adopted for preservation, since productive processes belonging to a closed system, in which there is no exchange with the external environment, it can achieve sustainability by the transformation of residues in by-products to other industrial processes. Thus, it follows from the law of the conservation of mass that, in identifying the emission of pollutants or residues into the environment, countermeasures must be sought to ensure that the consumption of raw materials does not lead to to depletion; hence, the practices of recycling and reuse are recommended (Sverdrup, Ragnarsdottir, & Koca, 2017). ...
... Usiminas has developed a practical application for one of the residues of its ore transformation process; previously, this residue was discarded as solid residue. The new destination for the material by Usiminas is in line with the approach outlined by Sverdrup et al. (2017), according to which companies must establish recycling and reuse practices in order to mitigate the environmental impacts resulting from their activities. The innovation process developed by Usiminas incorporates the mitigation of social and environmental problems, as proposed by Barbieri et al. (2010). ...
A atividade econômica da indústria gera benefícios, como crescimento econômico, e malefícios, como resíduos descartados no meio ambiente. A possibilidade de mitigar os malefícios da atividade industrial, por meio de inovações sustentáveis, posiciona-se como tema de interesse para a sociedade. Neste contexto, esta pesquisa analisa o escopo das inovações socioambientais que a siderurgia brasileira implementa para mitigar a geração de resíduos sólidos. O desenvolvimento da pesquisa foi baseado em um estudo de caso na Usiminas, uma das maiores siderúrgicas da América do Sul, utilizando técnicas de análise de documentos e entrevistas com representantes da empresa. Os dados indicam que, por meio de um grupo multidisciplinar, a empresa desenvolveu quatro produtos que utilizam a escória da produção de aço com oxigênio como insumo. Embora o produto seja patenteado e seu valor seja negociado, o modelo de negócios adotado foi projetado para contribuir com o município. Como contrapartida, o beneficiário municipal desenvolve projetos para proteger as fontes de água. Dessa forma, as inovações tecnológicas podem transformar o resíduo dos processos da indústria em produtos que beneficiam o meio ambiente e a sociedade.
... This has led to cleaner and more efficient mobility systems than current ones being promoted from various institutions, including electric mobility. However, electrical mobility, a priori more environmentally friendly, has the associated problem that some of the materials present in several of the elements of this technology, such as electric motors and batteries, are critical elements [4], that is, can present problems of exhaustion in the near future [5], [6]. Several authors have pioneered attempts to draw attention to the problem of the depletion of mineral resources needed in the different technologies used to reduce GHG emissions and the use of fossil fuels in modern societies, such as photovoltaic technology or electric vehicles. ...
... Iron copper(kg/km) 10836 Finally, Table 6 lists the current reserves, resources [28], [29] and recycling situation [6], [30], [31] (stating their recycling ratios) of the main metals used in electrical mobility. Recycling ratios come from UNEP [30], except lithium, which come from Melin [31]. ...
Today, we are witnesses to the early days of a change in the mobility technology as oil reserves decline and society's environmental awareness increases. Electric technologies are intended to replace those based on hydrocarbons as they have been initially conceived as more environmentally friendly and energy efficient. However, the problem of the future availability of the materials required for this change has arisen. A large demand for this type of mobility could contribute to the depletion of these resources, leading to major problems for the manufacture of vehicles and all other technologies that use these materials if we do not find alternatives that allow us not to deplete these natural resources. These alternatives may involve not only a change in the materials used in electric vehicles but also the use of different modes of transport. To help us estimate which materials related to the transition in the transport sector might be most critical in the future globally, the MEDEAS system dynamics simulation model will be used. Once the simulations on different scenarios have been run, we observe how aluminium, copper, cobalt, lithium, manganese and nickel have such a high demand that would practically cause the exhaustion of their reserves in several scenarios, so we will propose alternative measures to try to avoid their exhaustion due to the use of this type of mobility. Keywords: Transport modes, mineral resources, system dynamics, lithium-ion batteries.
... These evolutions are increasing the pressure on the global supply chains, which in turn contributes to risks of scarcity for various metals [2,3]. The extraction of metals from primary geological sources as well as recycling from end-of-use consumer goods have to adapt to meet this soaring demand [4,5]. ...
... High leaching rates were obtained (>90% for both metals). The color of the DES turned to blue after the leaching, which was attributed to the formation of the CoCl 4 2anion. Thus, leaching of the metals seems to occur via coordination with chloride from the ChCl HBA. ...
Deep eutectic solvents (DESs) appeared recently as a new class of green designer solvents. The recovery of metals using hydrometallurgy is of major importance with the growth in metal demand. Several authors used these solvents for the hydrometallurgical recovery of metals from primary and secondary resources, and these studies are reviewed in the present work. Hydrophilic DESs can be used for the leaching of metals and have great potential to replace mineral acids, and even to reduce water consumption. Efficient and selective leaching of metals from minerals or wastes is feasible by using DESs. However, the kinetics of leaching as well as the physicochemical properties of DESs are still limiting their large-scale application. Electrochemical recovery from DES is also possible but deserves further investigation. Finally, the recovery of metals from aqueous solutions using hydrophobic DESs was studied in several works. For the solvent extraction of metals, hydrophobic DESs constitute credible alternative ionic liquids.
... Major renewable resources consisting of recyclable metals, including Fe, Al, and Pt [7], occupy 80%. According to the latest estimate by Sverdrup et al. [8], scrap will be the primary source for Fe, Al, and Cu in the next three decades. Nevertheless, enterprises in China's auto recycling and dismantling industry are still operating in a relatively crude manner. ...
Recovering copper foil and crushed aluminum from end-of-life vehicles (ELVs) is a significant issue in the recycling industry. As a key technology for sorting aluminum, copper, and other non-ferrous metals, eddy current separation (ECS) is efficient in isolating the non-ferrous metals according to their different electrical conductivity and density. However, further research is still needed in the separation of large-size copper foil and crushed aluminum from scrapped vehicles. In this study, support vector regression (SVR) and the sparrow search algorithm (SSA) are exploited for the first time to be used in optimizing the Halbach magnetic roller. Firstly, the numerical simulation results are based on the response surface methodology (RSM). Then, the accuracy of four kernel functions employing SVR is compared to select a kernel function. The sparrow search algorithm (SSA) is proposed to optimize the structural parameters of the Halbach magnetic roller, concentrating on the above-selected kernel function. Meanwhile, the parameters are confirmed. Numerical simulation results indicate that machine learning for magnetic roller optimization is feasible.
... Soil pollution is, thus, one of the greatest sustainability challenges that our society faces today [7]. Inorganic pollutants may originate from anthropogenic processes such as applications of impure P fertiliser containing Cd, but geogenic sources such as weathering and volcanic eruptions are often equally important in terms of risks to human health [2][3][4]8]. Metals and metalloids are sometimes naturally present at toxic levels in the soil [9]. ...
Soil pollution is a threat to food security and ecological and human health. Cd is one of the most common pollutants in agricultural soil and, due its human toxicity, one of the most hazardous. Amaranth is a documented hyperaccumulator of Cd and other pollutants, and it is commonly grown in Asia and South America. A considerable amount of amaranth is grown in suboptimal conditions, including nutrient-poor acidic soils. The objective of this experimental study was to examine the capacity of Amaranthus hypochondriacus to extract Cd from a nutrient-poor, acidic substrate that was spiked with different concentrations of Cd (2 and 20 mg kg−1 dw) during a period of 180 days. The plants grown in the substrate that was spiked with 20 mg Cd kg−1 dw did not develop into mature plants, but the plants grown in substrate that was spiked with 2 mg Cd kg−1 dw extracted a significant amount of Cd from the substrate by accumulating it into the above-ground biomass. The Cd levels varied from 113 to 176 mg kg−1 in the stems at the four measuring points, and from 64 to 94 mg kg−1 in the leaves. The concentrations in the plants increased with time and reached a maximal concentration of 176 ± 45 mg kg−1 dw for stems and 94 ± 41 mg kg−1 dw for leaves after 180 days. The mean bioaccumulation factor in the plants was 86 ± 15 after 90 days, 72 ± 12 after 120 days, 105 ± 37 after 150 days, and 99 ± 31 after 180 days, which confirms the previously reported capacity of Amaranthus hypochondriacus to hyperaccumulate Cd. Amaranthus hypochondriacus may, thus, be used to improve ecological and human health by remediating moderately Cd-polluted soils, even in nutrient-poor acidic soils.
... For instance, BEV trucks contain large batteries that can weigh up to five metric tons and requires significant amounts of metals like lithium and cobalt as part of the manufacturing process. By year 2050, these metals are projected to be scarce (Castelvecchi, 2021;Chitre et al., 2020;Sverdrup et al., 2017). Hydrogen powered trucks can either utilize hydrogen fuel cells or directly combust hydrogen. ...
We must move toward electrification of the transportation sector to help mitigate the adverse impacts of climate change. Carbon emission reduction in long-haul freight transport should be developed and administered given it accounts for 22% of transportation related emissions worldwide. Although electrified transport can make tail-pipe vehicle carbon emissions negligible, it does not mean that the entire system that supports electrified transport is carbon-neutral. We address this latter point in the present study by conducting a cradle-to-grave life cycle assessment of long-haul electric trucks that are powered by overhead cable lines (OCL). The environmental impacts were compared with those of battery electric vehicle trucks (BEV), and conventional diesel-powered trucks. The techno-economic analysis of long-haul freight OCL technology was conducted based on data from pilot-scale studies in Germany. The feasibility of implementing this technology in other countries was examined by comparing environmental impacts across respective electricity mixes. Results show that the environmental and economic impacts of OCL technology depends on the adoption percent. After analyzing different adoption rate scenarios, OCL adoption was found to be economically and environmentally beneficial at the 10% adoption rate or higher. We also found that use phase electricity accounts for over 83% of the net greenhouse gas emissions, thereby making the electricity mix powering this technology a determining factor for implementation around the world. Across their life cycles, the carbon footprint of both OCL and BEV was 2.5 times lesser than that of the conventional truck. Other findings reveal adaptable methods, a unique environmental-to-economic ratio measure, and equity considerations that can be leveraged for immediate decision-making activities and future studies alike.
... Depleting reserves poses another risk to the tantalum supply. Estimates see the peak production of tantalum in 2005 (Sverdrup et al., 2017) or in 2039 (Calvo et al., 2017) and a static index of depletion of 50 years (Althaf and Babbitt, 2021). ...
... It is not the pure amount of minerals available in the Earth's crust that limits the exploitation of resources, but the (external) costs for the mitigation of the impacts of mining of the resources on the surrounding environment and the global climate. Calvo et al., Ragnarsdottir et al., and Sverdrup et al. used Hubbert's peak approach for estimating the ultimately available amount of mineral resources, whereas, with the same goal, Rankin extrapolated the results of an extensive assessment of the US Geological Service of the undiscovered deposits of gold, silver, copper, zinc, and lead in the USA to a global scale [5][6][7][8][9][10][11]. Tilton states that it is impossible to provide predictions on the ultimately available amount of mineral resources [12,13]. ...
Much attention is being paid to the short-term supply security of raw materials for the energy transition. However, little attention is being paid to the impact of the energy transition on the long-term availability of a number of specific mineral resources that are needed for the realization of a fossil-free energy infrastructure. The aim of this paper is to examine whether the quantity of raw materials required for the energy transition could encounter limits of geological availability of mineral resources, especially in the case that energy supply and consumption are equitably distributed over all countries of the world in the long term. This study is an ex ante evaluation. The result of the evaluation is that four metals are relatively problematic: cobalt, copper, lithium, and nickel. The in-use stocks of these four metals in energy transition-related technologies may take up between 20% and 30% of the ultimately available resources of these metals in the continental Earth’s crust. Even with an 80% end-of-life recycling rate, the increase in the annual use of primary resources is estimated to be 9% for copper, 29% for nickel, 52% for cobalt, and 86% for lithium, compared to the estimated annual use of these metals without an energy transition. The conclusion of the study is that the question of whether energy equity and the energy transition are a compatible combination cannot be answered unambiguously. After all, it will depend on the extent and the speed with which cobalt, copper, lithium, and nickel can be substituted with other, geologically less scarce metals, and on the achieved end-of-life recycling rates of these metals, not only from energy transition-related products, but also from all other products in which these metals are applied. The novelty of the study is that the availability of raw materials for the energy transition is analyzed from a perspective of global equity at the expected level of the European Union in 2050.
... Given we have already argued for the importance of price feedbacks, we will focus on approaches that incorporate market clearing of both supply and demand (for common supply and demand modeling approaches, see the review by Watari et al., 2021). Broadly speaking, metals markets are studied using (i) econometric models (Fisher et al., 1972;Fu et al., 2017;Watkins & McAleer, 2004), (ii) agent-based models (Bollinger et al., 2012;Cao et al., 2021;Riddle et al., 2015), and (iii) system dynamics models (Elshkaki, 2013;Sprecher et al., 2015a;Sverdrup et al., 2017) or a combination of the three (Ryter et al., 2022). ...
Raw materials costs form an increasingly significant proportion of the total costs of renewable energy technologies that must be adopted at unprecedented rates to combat climate change. As the affordable deployment of these technologies grows vulnerable to materials price changes, effective strategies must be identified to mitigate the risk of higher input costs faced by manufacturers. To better understand potential threats to deployment, a market modeling approach was developed to quantify economic risk factors including material demand, substitutability, recycling, mining productivity, resource quality, and discovery. Results demonstrate that price changes are determined by interactions between demand growth, mining productivity, and resource quality. In the worst cases with high demand and low productivity, development of material substitutes and large recycling rates help reduce the prevalence of price risk from ∼90% to under 10%. Investing in these strategies yields significant benefits for manufacturers and governments concerned about costs of materials critical to decarbonization and other advanced technologies.
... Traditional methods are only able to accomplish the recovery of metals such as iron and aluminum, and high recovery rates exist only for ferrous and base metals primarily (Hagelüken et al., 2016). In economically underdeveloped regions or countries, the recycling of scrap electronics is separated by manual sorting, but it requires enough scrap collection and the ability to recover precious metals such as palladium, platinum, and gold in the scrap to be economically viable (Sverdrup et al., 2017). In automated recycling operations, magnets and sensors will be used to help separate materials. ...
Visual recognition technologies based on deep learning have been gradually playing an important role in various resource recovery fields. However, in the field of metal resource recycling, there is still a lack of intelligent and accurate recognition of metallic products, which seriously hinders the operation of the metal resource recycling industry chain. In this article, a convolutional neural network with dual attention mechanism and multi-branch residual blocks is proposed to realize the recognition of metallic products with a high accuracy. First, a channel-spatial dual attention mechanism is introduced to enhance the model sensitivity on key features. The model can focus on key features even when extracting features of metallic products with too much confusing information. Second, a deep convolutional network with multi-branch residual blocks as the backbone while embedding a dual-attention mechanism module is designed to satisfy deeper and more effective feature extraction for metallic products with complex characteristic features. To evaluate the proposed model, a waste electrical and electronic equipment (WEEE) dataset containing 9266 images in 18 categories and a waste home appliance (WHMA) dataset containing 11757 images in 23 categories are built. The experimental results show that the accuracy reaches 94.31% and 95.88% in WEEE and WHMA, respectively, achieving high accuracy and high quality recycling.
... The main application of Sb is for flame-retardants, but it is also used in the production of lead-acid batteries, in the electronic industry, in pigments, pesticides, medicines, and detonators. Some of the main applications of Bi are the same as those of Sb, in addition to being applied in cosmetics and in the pharmaceutical industry [8,[10][11][12]. Bi-Sb alloys are also valuable materials with good solderability and high corrosion resistance, being often used as semiconductors in electronics [13][14][15][16]. ...
Antimony (Sb) and bismuth (Bi), which have been considered critical raw materials by the European Commission, cause inconveniences to copper production when they are present as impurities in copper electrorefining solutions. Therefore, ion–exchange resins to extract Sb and Bi from copper-containing electrolytes have typically been applied; after the adsorption of the metals, the elution step is conducted with an HCl solution to desorb them. In the present study, a novel membrane electrolysis system with a cation–exchange membrane was proposed to extract Sb and Bi ions from the elution solution, and a cyclic voltammetric study was carried out to evaluate the influence of the most important operating parameters on the process performance, such as Sb, Bi and HCl concentration, dilution factor of the solution, the presence of thiourea as a complexing agent, the presence of iron as an impurity, and temperature. The obtained voltammograms indicated that the simultaneous presence of the metals in solution alters considerably their electrodeposition and oxidation pattern when compared to the solutions with pure metals. The reactions of electrodeposition of both metals are not electrochemically reversible and the diffusion control for bismuth is greater than that for antimony. The increase in the concentration of Sb affects its electrodeposition kinetically, whereas that of Bi is affected both kinetically and thermodynamically. The increase in HCl concentration disfavors the electrodeposition of both metals. Diluting the solution reduces the energy consumption and prolongs the membrane lifespan. Increasing the temperature reduces the cathodic potential to deposit the metals but favors the hydrogen evolution reaction. The presence of iron as an impurity does not affect the electrodeposition of both metals, whereas the use of thiourea as a complexing agent must be avoided because it impairs their electrodeposition.
... While antimony has been analyzed in traditional metal criticality studies (e.g. Hayes et al. 2018, Panousi et al., 2020, Gemechu et al., 2015, Chakhmouradian et al., 2015, Nuss and Blengini, 2018, Sverdrup et al., 2017, Henckens et al., 2016, it has not been studied from a resilience perspective. Traditional criticality studies mainly look at static parameters such as diversity of supply and stability of regimes in source countries. ...
Antimony is considered a critical and strategically important metal and is used in a wide range of products. This study examines major antimony supply chain disruptions from 1913 to 2018 and analyses how resilience mechanisms and price feedback loops contributed to supply chain resilience. We found that the antimony diversity of supply of both mining and refining is low, but is enhanced by recycling, around 25% of global antimony supply is produced via recycling of antimony bearing metal alloys. Based on production volume, almost 70% of antimony was mined as by- or co-product in 2018, indicating a high supply risk. However, the presence of unrecovered by-products can also make the supply more elastic. Substitution is possible for some antimony applications, but for one of the main applications, flame retardants, performance of substitutes is still considered inadequate. Overall, stockpiling played a significant role in both dampening and exacerbating supply disruptions. It is recommended that the mined production and processing capabilities are diversified, stockpiles are explored as a mechanism to absorb sudden shortages, and, most importantly, recycling of antimony (trioxide) should be further improved.
... The demand for these secondary products also depends on government intervention. Even though the government has purchasing power with regards to secondary products, lack of cooperation and communication hinder positive government intervention on the manufacturing of secondary products (Sverdrup et al., 2017;Tennakoon et al., 2021). Likewise, Yu et al. (2017) further stressed that the complexity of the demolition process and the lack of rigorous implementation of regulations in the recycling process have failed to enable effective decision-making. ...
Purpose: Reverse Logistics Supply Chain (RLSC) for demolition waste management is a complex process that inherits significant interdependent risks. However, studies on RLSC have not explicitly identified the risks of its inter-relationships by disentangling their effects on operational performance. Accordingly, this paper aims to identify and assess the inter dependencies of the risks in RLSC, to improve quality-related operational performance.
Design/Methodology/Approach: A sequential exploratory mixed-method research approach, consisting of qualitative and quantitative methods was employed. The qualitative approach involved 25 semi-structured interviews, whereas the 18 subsequent structured interviews were conducted with stakeholders in the entire RLSC as part of the quantitative method. These used to identify the cause-and-effect relationships of the identified risks. The data was analysed using thematic analysis and the Bayesian Belief Network (BBN) technique was used to develop a conceptual risk model.
Findings: 20 risks in four RLSC sub-processes, namely, dismantling, and on-site process, off-site resource recovery process, marketing of secondary products and residue disposal emerged. Among cause-and-effect relationships of identified risk factors, inferior quality of secondary products were found to have the strongest relationship with customer satisfaction. Under-pricing of dismantling job, improper landfill operations, and inadequacy of landfill levy are independent risks that initiate other risks down the supply chain. The aggregate effects of these risks affect customer dissatisfaction of the end-product, as well as health and safety risks in on-site, off-site and residue disposal.
Research Limitations/Implications: This study only identify the cause-and-effect relationships of the identified risks within RLSC for demolition waste management operations for DWM. It has not been targeted a specific construction material or any secondary production, which could be practiced through a case study in future research
Practical Implications: The results encourage the investigation of RLSC process quality by maintaining the relationship between recycler and customer to enable a safe workplace environment. Hence, the role of relevant practitioners and government are inseparable in supporting decision-making. Future research could discuss the impact of those interrelated risks in relation to time- or cost-related operational performance criteria.
Originality/Value: This study contributes to the field through presenting the first major study on the identification and assessment of the inter dependencies of the risks in RLSC in South Australia. The RLSC process mapping had been identified as a tactical and operational management approach. However, the risk management process is a strategic management approach. Therefore, the integration of both process mapping and the risk management approaches in one platform is germane to construction management research.
... Iron, aluminium and copper are not only the main metals required in the electricity sector; they are also considered the most important metals for the infrastructures of modern societies (Sverdrup et al., 2017). Although the global peak production of these metals is estimated to occur within the next two or three decades (ibid.), ...
Transforming and expanding the electricity sector are key for climate change mitigation and alleviation of energy poverty. Future energy systems based on renewable energy sources may reduce greenhouse gas (GHG) emissions but could require more materials during construction. We assess this trade-off by quantifying the requirements of the main bulk materials used in electricity infrastructures for 281 global electricity sector pathways until 2050. We identify main determinants for material requirements and gauge the relevance of socio-economic framework conditions and climate change mitigation regimes. Five selected, highly diverse scenarios are analysed in detail by quantifying their respective annual material stocks and flows, and cumulative GHG emissions to 2050. We find robust evidence that scenarios in line with the 1.5 °C target are associated with significantly higher material requirements than scenarios exceeding a global temperature rise of 2 °C. Material stocks in 2050 differ by up to 30% for copper, 100% for concrete, 150% for iron/steel and 260% for aluminium (3rd quartiles of Monte Carlo simulations), even when the particularly material-intensive “Below 1.5 °C″ scenarios are excluded. Although power plants account for the largest part of the material requirements, grid expansion and reinforcement, necessary to accommodate large shares of volatile power generation and provide universal access to electricity, also cause substantial material demand. In the absence of future GHG mitigation in the processing industries, GHG emissions related to bulk materials (primarily iron/steel and aluminium) could amount to one tenth of the remaining carbon budget for a 50% chance of limiting global warming to 1.5 °C. However, if preference is given to material-efficient technologies, low-carbon processes are applied in the industries and increased material recycling is achieved, GHG emissions related to bulk materials in decarbonisation pathways will not significantly exceed those in largely fossil fuel-based scenarios.
... Lead-antimony alloys have also several applications, such as in corrosion-resistant pumps and pipes, roofing sheets, solder, and cables [33,141,142]. In addition to some above-mentioned applications, bismuth is used in cosmetics and in the pharmaceutical industry [143,144]. Bi-Sb alloys are also used as semiconductors in electronics [145]. The widespread use of antimony and bismuth and the growing concerns regarding their scarcity point to the need to recover these metals in the copper electrorefining stage. ...
The mining industry has faced significant challenges to maintaining copper production technically, economically, and environmentally viable. Some of the major limitations that must be overcome in the coming years are the copper ore grade decline due to its intense exploitation, the increasing requirements for environmental protection, and the need to expand and construct new tailings dams. Furthermore, the risk of a supply crisis of critical metals, such as antimony and bismuth, has prompted efforts to increase their extraction from secondary resources in copper production. Therefore, improving conventional processes and developing new technologies is crucial to satisfying the world’s metal demands, while respecting the policies of environmental organizations. Hence, it is essential that the chemical composition of each copper production stage is known for conducting these studies, which may be challenging due to the huge variability of concentration data concerning the ore extraction region, the process type, and the operational conditions. This paper presents a review of chemical composition data of the main stages of copper production from sulfide minerals, such as (1) copper minerals, (2) flotation tailings, (3) flotation concentrates, (4) slags and (5) flue dust from the smelting/converting stage, (6) copper anodes, (7) anode slimes, (8) contaminated electrolytes from the electrorefining stage, (9) electrolytes cleaned by ion-exchange resins, and (10) elution solutions from the resins. In addition, the main contributions of recent works on copper production are summarized herein. This study is focused on production sites from Chile since it is responsible for almost one-third of the world’s copper production.
... There is a real risk due to metal scarcity and to the impact of exploration of these metals involving geopolitical risk and human rights abuse [29]. Therefore, recycling and the technical loops are strategies to ensure resource availability over time [30]. The social factor analysis considered the improvements to reduce the ergonomic risks. ...
Product-Service System (PSS) is a sustainable strategy that shifts the focus of the business from selling physical products to providing service by using the product. The innovation proposed in the PSS, focused on sustainable production and consumption, is consistent with the sustainable development goals of the United Nations 2030 Agenda. The scientific literature on PSS in machining showed studies that address the economic factor of PSS contract, machine maintenance and logistics and operational process improvement. Then, there is a lack of studies on the assessment of the PSS in machining under a sustainability factors perspective. Thus, the objective of this paper was to evaluate the economic, environmental, and social advantages of PSS cutting tools in machining. Consistent with this aim, the research focused on a case study in a diesel engine parts machining company. From an economic point of view, the results indicated a reduction in operating costs of US$ 1,206,080 per year, which allowed a nine-month return on investment. From an ecological perspective , the recovery of 602 kg of carbide per year mitigated the environmental impact of tungsten and cobalt exploration. These results are even more expressive because it deals with scarce metals. Furthermore, technological advances reduced the risk of injury to operators. This research increased knowledge on PSS in machining by presenting an original study that led the analysis under a sustainability perspective. Moreover, this study contributes to managers by showing the business model's advantages that reduce operating costs and socio-environmental impacts, enhancing sustainable development.
... The main issue of nanotechnology is the handling nanowaste materials after reusing them, since they are particles with extremely small sizes, which make them difficult to monitor and track. Meanwhile, because this technology is a very recent topic, there is not enough knowledge about their waste treatment and the implications for the environment [18,19]. Environmental issues with nanowaste are getting worse compared to bulk materials as a result of various classifications, such as synthetic and natural, inorganic and organic, spheres and clusters, wires, nanofibers, plates, and thin films. ...
This chapter discusses the potential usage of recycled nanomaterials in industrial applications and explains scalable technologies for the recovery of nanomaterials from composite systems. Relevant regulations for waste management are also described to follow the standards and achieve the authorization of recycled nanomaterials. This chapter addresses the approaches to cost-effective material separation, recycling, and recovery and assesses environmental sustainability. In addition, this chapter contributes to the circular economy movement by promoting sustainable development by utilizing sustainable materials (waste nanomaterials) and adopting environmentally friendly production processes. Recovery of nanomaterials from the selected matrix, which can be polymers or biobased systems, can be achieved by developing new protocols and methodologies such as electroplating, thermal treatments, upcycling, and selective recovery processes. Therefore current research developments related to nanomaterials recycling for industrial applications are elaborated by providing specific examples from different fields and considering environmental issues.
... The relative scarcity of literature on this topic is opposed to other more mainstream metals whose ESG coverage is high, e.g., Co (van den Brink et al., 2020, Chen et al., 2020, Fu et al., 2020, Rare earth elements (Weng et al., 2016, Arshi et al., 2018, Fe (Nuss et al., 2014), Au (Andrews andEssah, 2020, Gifford et al., 2010), and Cu, Pb and Zn (Seck et al., 2020, Liu et al., 2020, Mudd et al., 2017, Sverdrup et al., 2017. The lack of studies into Ti and Zr contrasts markedly with minerals related to battery storage and green energy production, where numerous studies exist (Sun et al., 2019, Sterba et al., 2019, Kowasch, 2018, Prior et al., 2013 including a number of commercial enterprises which have launched their own research offerings and commissioned studies (Roskill, 2020, BMW, 2020. ...
The growing focus on environmental responsibility from the community, investors and regulators presents immense challenges and opportunities to mining companies. Titanium and zirconium minerals are vital, unrecyclable, and often irreplaceable components of modern infrastructure and technology. The companies which supply these minerals often have a long-history of sustainability reporting. Such reports have been used here to analyse energy usage, carbon dioxide emissions and water usage from mining and processing these minerals. Mining operations and titanium-slag producers in Australia, Canada, China, Mozambique, Madagascar, Norway, and South Africa were analysed. This paper presents both site-specific data as well as data generalized to heavy mineral sand (HMS) deposits vs igneous hard-rock style deposits, as well as those products which have undergone beneficiation. In terms of averages, energy use was higher for HMS (yearly average of between 0.90 – 2.95 GJ/t valuable heavy mineral (VHM)) compared to ilmenite-dominant hard-rock mining (yearly average of between 0.21 – 0.49 GJ/t ilmenite) and Ti-slag production required between ∼10 – 14 GJ/t of saleable product (including titanium slag and pig-iron). Emissions from ilmenite-dominant hard rock mining produced ∼0.01 t CO2e/t ilmenite concentrate while HMS mining produced 0.07-0.38 t CO2e/t of VHM; emissions from beneficiating ilmenite into Ti-slag add significantly to this (0.62-1.21 t CO2e/t of saleable product, weighted by value). Overall, hard-rock mining operations consumed <5 kL/t ilmenite concentrate while HMS consumed 10-26 kL/t VHM. On the other hand, beneficiating hard-rock ilmenite into slag increases water-use by ∼220 kL/t of saleable product. Finally, in terms of land use, it was determined that an average of 4.3 ha per 1 Mt of ore was disturbed in HMS operations (no data was available for hard-rock operations). While average results comparing HMS, hard-rock and beneficiated products were broadly comparable to existing LCA literature, data used in LCA literature is not consistent with specific sites and using generalized data to infer site-specific data will often lead to erroneous estimates. These observations taken together are particularly important to downstream purchasers, as well as the investment community who do not fund entire industries, but fund and back specific projects; the decision made on which site or company to invest in is increasingly determined by environmental, social and governance (ESG) related factors. This paper not only provides quantitative indications of these factors for Ti/Zr production, but also guidance for improving sustainability reporting in the industry. An improvement in the quality, quantity and consistency in this data, as this paper explains, will allow for greater information to guide investment and ESG outcomes for Ti/Zr industries.
... The mining and smelting of these materials have been fairly well documented and its environmental impacts are generally understood (Kosai and Yamasue, 2019). The environmental effects of mining are substantial and thus recycling materials should be strongly considered during the pre-manufacturing process due to economic and environmental considerations (Sverdrup et al., 2017). The powder formation process is generally referred to as the atomization process. ...
Additive manufacturing (AM), also known as 3D printing is a relatively new concept and promising technology for industrial production. It is important to investigate the environmental impact of the AM process in light of the environmental critical situation of the Earth. The elimination of some costly prefabrication processes such as molding or post-fabrication stages such as machining and welding required in traditional manufacturing methods favor the AM process and provide beneficial economic advantages. Furthermore, the reduction of manufacturing steps contributes to environmental protection through fewer operations, less material, and energy consumption, and reduced transportation. This study is a review for the assessment of environmental impact and life cycle of some well-known AM technologies for manufacturing metallic parts and components. The fabrication of a pump impeller is simulated through a well-known metal production AM technology and casting process for direct comparison. Life Cycle Assessment (LCA) is applied to measure the environmental impact in five different stages of pump impeller lifetime with the two different fabrication processes. AM compared to casting has an environmental impact reduction potential of 15%, 20%, 65%, 20%, and 10% respectively in Global Warming Potential (GWP), Acidifications Potential (AP), Water Aquatic Eco-toxicity Potential (FAETP), Human Toxicity Potential (HTP), and Stratospheric Ozone Depletion (ODP). Using hydroelectricity and renewable electricity mitigate the environmental impact of the AM process in pre-manufacturing and manufacturing stages temporarily until the advancement of AM technology for consuming less energy. Recommendations for future research to enhance the environmental sustainability of the AM process is proposed as outcomes of this study.
... CIGS is a well-known material with good optical properties [3]. Therefore, the CIGS thickness range of 2-3 lm is still being used for sufficient light absorption [3][4][5][6]. Lightweight and ultrathin flexible solar cell devices are particularly attractive in the markets which use fewer materials and hence reduce production time with lower-cost labor [6][7][8][9][10][11][12][13][14][15][16]. ...
This paper presents an investigation of ultrathin Cu (In1−xGax) Se2 solar cell which was calibrated from the fabricated cell using Silvaco-TCAD tools. Carrier transport mechanism and conduction band alignment at the CdS/CIGS interface shows a large influence on PV parameters. The influence of the absorber trap density on the electrical characteristics of the single junction cell was investigated under AM 1.5G one-sun (100 mW/cm2) illumination. Further simulations quantify significant improvements in cell efficiency while using a thin Al2O3 material as a rear passivation layer. In addition, the impact of the backside pitch size, opening width, absorber layer doping, and thickness on cell performance is investigated to enhance the cell efficiency. To evaluate our work, the electrical characteristics of the optimized cell were compared to the fabricated cells.
... While methods for recycling selenium from waste, including from CIGS solar cells [e.g., 88], do exist, there is no widespread recovery of selenium from old scrap [87]. Risk in the supply chain of selenium comes from the nature of the extraction, whereby production is highly dependent on copper production, along with its low geological abundance in Earth's crust [89]. In a comparison of the supply risk of critical metals, Graedel et al. (2015) [34] found that while selenium had low environmental risk, the overall supply risk was very high. ...
The Paris Agreement set a goal of limiting the Earth’s average temperature increase in order to reduce the threat of climate change. Fundamental to achieving this goal will be a large global increase in renewable energy generation and storage capabilities, particularly photovoltaic cells, wind turbines, batteries, and fuel cells. However, an often overlooked aspect of a large scale shift to renewable technologies is the increasing demand this creates for the mineral resources used in their manufacture. Some of these minerals have high-risk supply chains that threaten their production, resulting from various economic, social, geopolitical and geological factors. These important and high risk minerals are known as critical minerals. Many of these critical minerals are abundant in extraterrestrial bodies, and the possibility of extracting resources from in space is now closer to reality than ever. With the potential to avoid many of the risks associated with their supply on Earth, combined with the current push towards renewable energy; an evaluation of extraterrestrial bodies as a resource to meet the demand for critical minerals is timely.
A set of eight critical minerals/mineral groups used in the manufacture of renewable energy technologies were identified in this study through an extensive literature review: lithium, gallium, selenium, silver, indium, tellurium, rare earth elements, and platinum. The potential of extraterrestrial bodies, namely the Moon and near-Earth asteroids, as a source of these critical minerals is investigated. We find that asteroids are likely to provide an important source of platinum, selenium, and gallium, and to a lesser extent, of silver, indium and tellurium. The case for extracting lithium and the rare earth elements from extraterrestrial bodies is less compelling. It is clear from this study that a reduction in the environmental and social impacts of producing these critical minerals is necessary. A strategy to extract minerals from extraterrestrial bodies would be a valuable step in achieving this.
... These large scale increases in final demand for minerals needs to be considered in the context of uncertainty over the scale of unexploited resources for some of these minerals. For example, Sverdrup et al, (2017) use an integrated WORLD and Hubbert's model to assess the future supply for a range of metals, highlighting that demand for most metals is predicted to peak within the next 40 years, especially for copper, zinc and nickel -all crucial to the low-carbon transition. Mudd & Jowitt (2018) on the other hand present a more optimistic picture for reserves, highlighting strong growth in the known mineral resources -discussing that the key factors governing the availability of resources are social, environmental and economic rather than geological or physical resource depletion. ...
The circular economy is a widely discussed topic in the field of Eco-industrial initiatives and environmentally responsive economies. The current economic and industrial model which is termed as the produce-use-dispose model is a linear model in which the resources are lost forever after their utilization; a waste of resources as well as money. In addition to economic impact, it creates immense pressure on the environment while disposing of the waste products. For this reason, scholars are trying to find an effective solution to this problem by ensuring the re-utilization of resources. The economic concept of the circular economy ensures the recycling and utilization of resources and closes the resource loop. In a world of reducing and often scarce natural resources, the recycling and utilization of resources increase the opportunities for economic growth-this is especially important given the rising demand for natural resources in emerging economies-exacerbated by the low-carbon transition. This study encompasses these ideas and explores the barriers, drivers and triggers of the circular economy transition for the mining industry. In this paper, authors review several circular economy initiatives taken by mining industries. The paper aims to demonstrate some common themes across three big mining companies with the help of content analysis; and evaluates the identified barriers, drivers and triggers of these circular economy initiatives. The authors argue that the mining industry might capitalize on the learning of other industries in relation to CE, enabling timely advancement of circular economy initiatives.
... Dasgupta and Heal (1979), Krautkraemer and others (1998), Tilton (2003), Simpson, Toman, and Ayres (2005), and Tilton (2018) are recent economic treatments of resource availability. Largely physical perspectives on resource availability include Ragnarsdottir (2008), Henckens, Driessen, andWorrell (2014), Northey, Mohr, Mudd, Weng, andGiurco (2014), Calvo, Valero, and Valero (2017), and Sverdrup, Ragnarsdottir, and Koca (2017). There is a large and diverse literature in econometrics on metal prices. ...
Scientists typically use physical indicators, such as average crustal abundance, and energy requirements in production, as measures of the availability of mineral resources. Economists, on the other hand, typically rely on measures such as prices, and extraction costs. This study investigates the role of crustal abundance, energy requirements, and other physical indicators in determining relative metal prices. The relationship between prices, and physical indicators is estimated statistically for a sample of 22 chemical elements over the period 1970–2013 using an economic market model. The results suggest that energy requirements in production explain 43% of observed variation in metal prices, crustal abundance 21%, and other physical indicators (toxicity, native metal status, and melting point) combine to explain 12% of the observed differences in metal prices.
... Due to this characteristic, this metal is indispensable in numerous alloys and stainlesssteel manufacturing (Considine, 2005); a usage that reaches more than 80% of its total production (U.S. Geological Survey, 2016). Moreover, studies have projected that there will be future shortage of molybdenum in the future (Marafi and Stanislaus, 2003;UNEP (United Nations Environment Programme), 2008;Rankin, 2011;Sverdrup et al., 2017;Vemic et al., 2017). Thus, there is an ever-growing urgency to recover this metal. ...
Molybdenum, a precious metal with important roles in industries, is projected to experience future shortage. Despite this, there is still no practical recycling process of this metal and around 25 thousand tons of molybdenum are discharged into wastewater annually. Biorecovery is a promising approach to resolve the above problem because of its high selectivity, high sensitivity, low running cost and low environmental burden. A bacterial molybdenum binding protein ModE has been constructed into yeast cells and named as ScBp5. In this study, the potential of genetic engineered yeast for recovering molybdenum from wastewater was further investigated. In order to stabilize the expression of ModE, strain ScBp5 was further modified by replacing promoter upstream of modE to generate ScBp6. The improvement of molybdenum adsorption efficiency by ScBp6 was confirmed especially in low concentration. The molybdenum isotherms parameters of ScBp6 was analyzed. To enable the usage as biorecovery agent in industrial settings, ScBp6 cells were immobilized using calcium alginate matrix, and the optimum immobilization conditions for ScBp6 were determined as 2% matrix density, 4 h of immobilization time, and 10 mg/ml cell density. The investigation of molybdenum adsorption kinetics by immobilized ScBp6 cells showed this adsorption was an efficient chemisorption. Overall, this research demonstrate the efficiency of immobilized yeast cell in molybdenum recovery.
... The assumptions on current recycling rates are taken from Sverdrup et al. [46]. In order to show what effects an ambitious recycling strategy has on the primary material demand, we assume a target EOL-RR of 80% in 2050 for all metals. ...
We assess the requirements for neodymium, dysprosium, lithium, and cobalt in power generation, storage and transport technologies until 2050 under six global energy scenarios. We consider plausible developments in the subtechnology markets for lithium-ion batteries, wind power, and electric motors for road transport. Moreover, we include the uncertainties regarding the specific material content of these subtechnologies and the reserve and resource estimates. Furthermore, we consider the development of the material demand in non-energy sectors. The results show that the material requirements increase with the degree of ambition of the scenarios. The maximum annual primary material demand of the scenarios exceeds current extraction volumes by a factor of 3 to 9 (Nd), 7 to 35 (Dy), 12 to 143 (Li), and 2 to 22 (Co). The ratios of cumulative primary material demand to average reserve estimates range from 0.1 to 0.3 (Nd), 0.3 to 1.1 (Dy), 0.7 to 6.5 (Li), and 0.8 to 5.5 (Co). Average resource estimates of Li and Co are exceeded by up to a factor of 2.1 and 1.7, respectively. We recommend that future scenario studies on the energy system transformation consider the influence of possible material bottlenecks on technology prices and substitution technology options.
Biofuels that are applied using advanced conversion technologies are promoted as green alternative to fossil fuels. The water footprint, the freshwater consumption, linked to current life cycles of such biofuels is much larger than the corresponding consumption associated with fossil fuels. Wind‐ and photovoltaic energy are also characterized by water footprints that are much lower than the corresponding consumption linked to biofuels. Food production and biofuel production increasingly compete for scarce freshwater resources and freshwater stress may increase when biofuel production expands. Availability of freshwater may be a limiting factor in biofuel production. Biofuel life cycles can also be associated with substantial water pollution burdens of nitrate, phosphate, pesticides, and organic substances. On the other hand, it has been proposed to use wastewater for the production of microalgal biofuels. So far, however, no full‐scale production based on this proposal that meets standards achieved by state‐of‐the‐art wastewater treatment facilities has been reported. In many respects relevant to green perspectives, except the consumption of geochemically scarce mineral resources, solar and wind‐based technologies tend to outperform biofuel‐based energy supply technologies. There would seem to be a case for modest expectations as to the share of biofuels that are applied using advanced conversion technologies in future energy supply.
The replacement of internal combustion engines by electric vehicles (EVs) is being promoted towards the decarbonisation of the transportation sector. EVs require important amounts of materials, some of which are...
The growing concern of migration against a linear economy toward a circular economy has raised several political agreements in different nations. Planned obsolescence plays a crucial role from this aspect as it fosters the buyer to own a new product before the actual need. Producers practice different mechanisms to deliberately design their products to become obsolete before the natural product life. In this study, publications concerning planned obsolescence were analyzed by performing bibliometric analysis that extracted various parameters including citation per paper (CPP), total citation (TC), and total papers (TP) to understand the development and structure of this area. The results of the most widely used Web of Science and Scopus databases were compared on factors such as leading ten productive and most cited authors, top journals, and countries. Later on, frequently used keywords were visualized with the help of a VOS viewer.KeywordsPlanned obsolescenceBibliometric analysisReplacement cycleSustainability
Metal resources are unevenly distributed throughout the globe but are crucial for the global economy. Many economies are highly dependent and vulnerable to material supply from other parts of the world. This situation can be alleviated by recycling, as regions devoided of important reserves exploit their own urban mine. In this study, we explored an increased domestic recycling scenario utilizing a stock-flow perspective combined with a hybrid input-output database (EXIOBASE). We applied a mass rebalancing procedure on the production and trade flows of ores and metals. We calculated the supply risk with the GeoPolRisk method for single and two-stage supply chains. Results show that recycling reduce the risk associated with trade for most of countries and materials for the metal supply chain, where recycling effectively takes place. In contrast, such risk decrease is not found in the ore supply chain nor in the combined ore and metal supply chain.
Nanotechnology-based industries are projected to grow from a multimillion-dollar industry to a few billions of dollars in the next few decades. The rate of nanotechnology production is very high as per global market scenario. With increasing penetration of nanomaterials (NMs) in our daily lives through consumer products, nanowastes and nanobyproducts are bound to circulate in the environment and our surroundings. These include the byproducts generated from nanotechnology processed products. This chapter discusses the various NMs or nanostructured byproducts and the nanowaste that is generated by various industries. Nanoparticles that are released into the atmosphere are contemplate as different categories of waste when compared to their bulk counterpart. NMs recycling offers many benefits in both environmental and economic terms. NMs can be recycled from both new and pure products (from nanomanufacturing) and used products (nanowaste from nanointegrated products). This chapter discusses various processes of nanobyproduct generation and utilization that will be part of the evolution toward green technology.
Clean energy technologies are emerging as a major contributor to the total energy supply. Some metals play irreplaceable roles in these technologies. The supply risk of metals used in clean energy technologies is gradually increasing. Hence, it is necessary to investigate the supply risks of these metals worldwide. In this study, a comprehensive assessment is conducted to quantify the supply risks of critical metals. The production of the metals is imbalanced worldwide. China, Russia, the United States, Canada, and Australia dominate the supply of these metals. China has the largest supply risk, and the main risk contribution is linked to mining governance and policy, which suggests that strengthening government regulations is necessary. The supply risks in the United States, Russia, and Canada are moderate, and most risks are associated with geologic availability and recycling restrictions. Al, Cu, Fe, Pb and Ag displayed high risks linked to geologic availability and recycling restrictions. Pd, B, Sb, W, Re, Ge and Ga exhibited high risks related to mining governance and policy and environmental sustainability. Difficult exploration processes and highly sensitivity market supplies increased the supply risk. This study provides an important reference for the strategic application of the metals in clean energy technologies in the future.
The applications of ILs in the preparation and recovery of several inorganic and hybrid
materials are promising. ILs can be generally applied for several materials, such as
metals, nonmetal elements, silicas, metal oxides, chalcogenides, and porous materials.
ILs offer high recyclability and can be cost-effective after optimization, making them
attractive and receiving a growing number of scientists. ILs can be considered green
solvents. The methods that implement ILs are sustainable and could be effective in
comparison to conventional methods. Future research will explore the synthesis of
cheap ILs, making use of cost-effective methods.
The extraction rate of some raw materials is relatively high in comparison with the economically exploitable amounts in the Earth’s crust. Within a period of a century or so, these materials may become difficult to afford for future generations, unless timely measures are taken to keep these materials also available for future generations. The price mechanism of the free market may not react timely enough to future geological scarcity. The free market price mechanism reacts to today’s and tomorrow’s developments but does not necessarily take account of the interests of future generations, which are still at least decades ahead. To overcome this limitation of the market, mineral resources governance and policy need to be designed, agreed upon and implemented at a global scale. We analyze and assess eleven different policy instruments for achieving a more sustainable use of eight scarce raw materials.
A mineral resource is exhausted if further extraction of that resource is no longer profitable due to financial, environmental, energetic, climate change, waste generation, water use, or social impact factors, or a combination of these. This does not mean that the mineral is depleted in an absolute sense, and a large amount may still be available in the Earth's crust.
Based on two different economic growth scenarios, we explore how long 36 elements and groups of elements will remain available for humanity. This depends on the availability of a resource in the Earth's crust and the annual extraction rate. A material may be relatively abundant in an absolute sense, but relatively scarce in an economic sense because the annual extraction rate is high. The opposite can also be true: a raw material may be rare in the Earth's crust but not scarce because the annual extraction rate is low.
In diesem Open-Access-Buch kritisiert Philipp Schäfer die Entwicklung der Circular Economy hin zu einem Selbstzweck. Um den Beitrag der Circular Economy zu einer nachhaltigen Entwicklung zu gewährleisten, muss sie stets Mittel zum Zweck sein und bedarf daher konkreter Zielsetzungen. Anhand eines ausführlichen Exkurses in die Fachliteratur zeigt der Autor, dass das primäre Ziel der Circular Economy keineswegs durch das Narrativ der schwindenden Ressourcen bestimmt werden sollte. Vielmehr sollte das Ziel die Minderung des Energieaufwands der Rohstoffbereitstellung und der damit verbundenen Treibhausgasemissionen sein. Anhand konkreter empirischer Beispiele zeigt der Autor auf, dass diese konzeptionelle Zielausrichtung zwingend notwendig ist, damit der Beitrag der Circular Economy zum Klimaschutz und damit zu einer nachhaltigen Entwicklung sichergestellt werden kann.
Der Autor
Philipp Schäfer hat an der Hochschule Pforzheim Ressourceneffizienzmanagement (B.Sc.) und Life Cycle and Sustainability (M.Sc.) studiert. Von 2017 bis 2020 hat er am Karlsruher Institut für Technologie mit Unterstützung der Landesgraduiertenförderung Baden-Württemberg promoviert. Derzeit ist er als Postdoc am Institut for Industrial Ecology der Hochschule Pforzheim tätig. Seine Forschungs- und Arbeitsschwerpunkte liegen in den Bereichen Life Cycle Assessment, Circular Economy und Ressourceneffizienz.
Hybrid halide perovskites have taken over the world of new generation photovoltaics (PVs) since their first implementation just a decade ago, thanks to their efficiency comparable to commercial solutions, ease of fabrication, flexibility and versatility. Despite their outstanding performances, the presence of lead represents a severe concern for their future commercialisation, due to its toxicity and associated risks to human health and its environmental impact. Lead-free perovskites offer a potential avenue to circumvent the problem. However, parameters such as material abundance, toxicity and environmental impact of potential lead-substituents are too often neglected. In this review, we put forward a different perspective, focusing on concepts such as cost, availability, sustainability and eco-friendliness required to justify the large-scale use of lead alternatives in the PV industry. Furthermore, comparative case studies with technologies based on lead-containing materials such as lead zirconate titanate, Pb(ZrxTi1−x)O3, also known as PZT, and CdTe solar panels are provided. Finally, it is argued that the advantages of using lead in photovoltaic panels – when including proper encapsulation and recycling – outweigh the risks associated with its manufacturing.
This Report is the first in a series of reports on decoupling to be published by the International Panel for Sustainable Resource Management. It aims at scoping the challenges of decoupling. On material flows, the Report gives quantitative assessments at a global scale, at national levels, classified into the four major categories of primary raw materials: construction minerals, ores and industrial minerals, fossil fuel carriers, and biomass. Globally, the extraction of raw materials is estimated to be between 47 and 59 billion metric tons (Gt) per year, with a clear tendency of further massive increases. Over one century, the use of construction materials grew roughly 34 fold, that of ores 27 fold, while biomass use, dominating material flows in the first half of the last century, increased only 3.6 fold.
The Report proceeds to delineate three different trajectories of resource consumption until 2050, assuming in all three cases that the populations of all countries will change according to the UN projections (medium variant). (1) A business-as-usual scenario assumes for developed countries a continuation of the decoupling as observed in the past and rising levels of resource consumption in all other countries to the level of the developed countries by 2050. Not surprisingly, this would lead to a tripling of global annual resource extraction and consumption, as poorer countries catch up with the consumption patterns of the rich. The planetary environmental impacts would be unbearably high. (2) A moderate contraction and convergence scenario assumes absolute reductions for the industrial countries to a consumption per capita of half of the rates for the year 2000 (contraction), while all other countries catch up to this (reduced) level by 2050 (convergence). For developing countries, this implies decoupling. Despite the structural changes in the dominant production and consumption patterns implied by this trajectory, it leads to a roughly 40% increase in annual global resource use and associated impacts. (3) A tough contraction and convergence scenario simulates a pathway towards keeping global primary resource extraction at the current level. This implies even more reduction in resource use for industrial countries and much stronger decoupling for developing countries. It is the only trajectory that in terms of fossil fuel consumption and related CO2 emissions complies with the climate protection targets set by the IPCC.
The process of modelling needs great care and must be followed systematically. A route from mental model, via Causal Loop Diagrams to structural models is suggested. Modelling software is suggested as a useful help. Models are nothing but pictures of our understanding and must be treated as such. Mistakes made in modelling inevitably go back to faulty understanding, and revision of the understanding is more important than calibrating this away. Model choice is highly specific of the questions asked, and as questions are many, so are the models needed to answer them. Therefore no specific biogeochemical model can be recommended before any other. The choice depends on the combination of questions asked and the data available for driving potential models. Most questions have no models ready for them, and the reader is urged to develop his own specific models, and take great care in communicating these. Often an existing bio-geochemical model can be used as point of departure, and either adapted for the new purpose or used as an inspiration for a new model. The best biogeochemical model to use is the one that answers the question in an adequate way with the smallest amount of time and money.
tThe authors have collected data for the silver market, shedding light on market size, stocks in society andsilver flows in society. The world supply from mining, depletion of the remaining reserves, reducing oregrades, market price and turnover of silver was simulated using the SILVER model developed for this study.The model combines mining, trade markets, price mechanisms, populations dynamics, use in society andwaste and recycling into an integrated system. At the same time the degree of sustainability and resourcetime horizon was estimated using different methods such as: 1: burn-off rates, 2: peak discovery earlywarning, 3: Hubbert’s production model, and 4: System dynamic modelling. The Hubbert’s model wasrun for the period of 6000 BC–3000 AD, the SILVER system dynamics model was run for the time range1840–2340. We have estimated that the ultimately recoverable reserves of silver are in the range 2.7–3.1million tonne silver at present, of which approximately 1.35–1.46 million tonne have already been mined.The timing estimate range for peak silver production is narrow, in the range 2027–2038, with the bestestimate in 2034. By 2240, all silver mines will be nearly empty and exhausted. The outputs from allmodels converge to emphasize the importance of consistent recycling and the avoidance of irreversiblelosses to make society more sustainable with respect to silver market supply.
The concept of “peak oil” has been explored and debated extensively within the literature. However there has been comparatively little research examining the concept of “peak minerals”, particularly in-depth analyses for individual metals. This paper presents scenarios for mined copper production based upon a detailed assessment of global copper resources and historic mine production. Scenarios for production from major copper deposit types and from individual countries or regions were developed using the Geologic Resources Supply-Demand Model (GeRS-DeMo). These scenarios were extended using cumulative grade-tonnage data, derived from our resource database, to produce estimates of potential rates of copper ore grade decline.
The scenarios indicate that there are sufficient identified copper resources to grow mined copper production for at least the next twenty years. The future rate of ore grade decline may be less than has historically been the case, as mined grades are approaching the average resource grade and there is still significant copper endowment in high grade ore bodies. Despite increasing demand for copper as the developing world experiences economic growth, the economic and environmental impacts associated with increased production rates and declining ore grades (particularly those relating to energy consumption, water consumption and greenhouse gas emissions) will present barriers to the continued expansion of the industry. For these reasons peak mined copper production may well be realised during this century.
The Limits to Growth standard run scenario produced 40 years ago continues to align well with historical data that has been updated in this paper, following a 30-year comparison by the author. The scenario results in collapse of the global economy and environment, and subsequently the population. Although the modelled fall in population occurs after about 2030 – with death rates reversing contemporary trends and rising from 2020 onward – the general onset of collapse first appears at about 2015 when per capita industrial output begins a sharp decline. Given this imminent timing, a further issue this paper raises is whether the current economic difficulties of the global finan cial crisis are potentially related to mechanisms of breakdown in the Limits to Growth standard run scenario. In particular, contemporary peak oil issues and analysis of net energy, or energy return on (energy) invested, support the Limits to Growth modelling of resource constraints underlying the collapse, despite obvious financial problems associated with debt.
Global aluminum consumption has exhibited significant growth in recent years, due to its useful properties. As this will result in a large amount of aluminum accumulation as urban mines, the exploitation of these urban stocks will be an important issue in the future. To examine the recycling potential of urban stocks, a dynamic material flow analysis on aluminum was conducted focusing on Japan, the United States, Europe and China. The concentrations of the alloying elements were also investigated, since carryover of alloying elements during recycling results in off-specification secondary metals and alloys. The recycling of aluminum scrap was optimized from the results of dynamic material flow analysis using multi-material pinch analysis. It was estimated that Japan, the United States, Europe and China have the potential to reduce their primary aluminum consumption to 60%, 65%, 30% and 85% of their present levels, respectively. In 2050, it is estimated that 11400 kt of primary aluminum will be required among the four countries, while 12400 kt of obsolete scrap will not be able to be recycled due to high concentrations of alloying elements.
Aluminum demand in Japan has grown significantly during the last few decades. For most uses, small amounts of other metals are added to the primary aluminum to make harder alloys, which are classified by the nature and concentrations of their alloying elements. Aluminum scraps from end-of-life products, which are used as raw materials for secondary aluminum, are often mixtures of several alloys. Therefore, not only the amount of scrap but also the concentrations of their alloying elements must be taken into account when assessing the maximum recycle rate of aluminum scraps. This paper reports a dynamic substance flow analysis of aluminum and its alloying elements in Japan, focusing on the alloying elements Si, Fe, Cu and Mn. We devised eight categories of aluminum end uses and 16 types of aluminum alloys. The amount of each alloy in each end-use category was estimated from statistical data. We then estimated future quantities of discarded aluminum in each of the eight categories using the population balance model. At the same time, we calculated the concentrations of the alloying elements in each of the end uses. It was estimated that the amount of aluminum recovered in Japan would be about 1800 kt in 2050, which is 2.12 times that recovered in 1990. Calculated concentrations of alloying elements in aluminum scraps showed good correlation with those of the measured data.
The supply of some natural resources is unlikely to keep pace with the increasing demands of a growing population. New technologies must be based on abundant materials if we are to achieve sustainable development.
Dynamic stocks and flows analysis was applied to the anthropogenic aluminum cycle in Italy in order to detect and quantify metal flows and in-use stocks over the years 1947-2009. The model utilized a top-down approach, including data for production, consumption, loss, and trade flows of aluminum. Seven end-use markets were considered, namely buildings and construction, transportation, consumer durables, machinery and equipment, electrical engineering, containers and packaging, and miscellaneous appliance types. The results of this dynamic stocks and flows analysis model quantified the contemporary anthropogenic reservoirs (or in-use stocks) of aluminum at about 320 kg per capita, mainly embedded within the transportation and building and construction sectors. Cumulative in-use stock represents approximately 11 years of supply at current usage rates (about 20 Mt versus 1.7 Mt/year), implying significant potential for recycling in the future as this stock comes out of use. Flow analysis revealed that Italy imports mainly unwrought aluminum and exports final products, while the main material losses occur during alumina refining and collection of old scrap: specifically, containers and packaging have the highest old scrap generation rate, but for the lowest recovery rate (50%). Increasing support to collection of scrap and initiatives oriented to aluminum recovery specifically would allow Italy to increase its reliance on domestic material, and may also allow a decline of the country import-dependence on primary sources. The dynamic stocks and flows model created here provides a quantitative historical record of the aluminum required by Italian society during important periods of development and provides guidance for future decision-making around the use of domestic secondary resources.
This paper analyses the anthropogenic stocks and flows of aluminum in mainland China from 1950 to 2009 using time-series data for mining, production, fabrication, manufacturing, trade, and loss rates, and applies a dynamic top-down method to model scrap generation. Results show that growth rates of all flows increased from decade to decade, with 75% of most of the flows taking place in the last two decades. Of the 230 Tg aluminum entering China's anthroposphere, only 34% accumulates in in-use stock, and China's per-capita in-use stock (58 kg) in 2009 is 12% of the per-capita in-use stock in 2006 in the United States (490 kg). In addition, the share of secondary aluminum in the production of unwrought aluminum was less than 25% after 2000. These results imply that China's in-use stock of aluminum is still too “young” and small to generate high quantities of aluminum scrap for domestic secondary aluminum production. Because of this, China still depends mainly upon primary aluminum. From the 1980s to the period of 1990 to 2009, China changed from a net exporter of raw materials into a net importer and from a net importer of manufactured products into a net exporter. In 2009, China's static depletion time of bauxite was less than 15 years. Given the potential to increase its in-use stock, a secure supply of bauxite may become a challenge for China in the near future. Three dynamics driving China's rapid increase of primary aluminum production (PAP) were identified, and their impacts from 1991 to 2009 were quantified. The first, demand for aluminum by domestic in-use stock, was the most significant factor driving China's PAP increase. The second dynamic, China's net export of aluminum in the metallic form, became an important factor in stimulating PAP's increase in the 2000s. Lastly, the impact of losses to the environment in the metallic form on PAP is substantial and stays that way throughout time. Minimizing losses represents an opportunity to offset some demand.
The easy mineral resources, the least expensive to extract and process, have been mostly exploited and depleted. There are plenty of minerals left to extract, but at higher costs and with increasing difficulties. The effects of depletion take different forms and one may be the economic crisis that is gripping the world system. And depletion is not the only problem. Mining has a dark side—pollution—that takes many forms and delivers many consequences, including climate change. The world we have been accustomed to, so far, was based on cheap mineral resources and on the ability of the ecosystem to absorb pollution without generating damage to human beings. Both conditions are rapidly disappearing. Having thoroughly plundered planet Earth, we are entering a new world.
Industrial assets or fixed capital stocks are at the core of the transition to a low-carbon economy. They represent substantial accumulations of capital, bulk materials, and critical metals. Their lifetime determines the potential for material recycling and how fast they can be replaced by new, more efficient facilities. Their efficiency determines the coupling between useful output and energy and material throughput. A sound understanding of the economic and physical properties of fixed capital stocks is essential to anticipating the long-term environmental and economic consequences of the new energy future. We identify substantial overlap in the way stocks are modeled in national accounting, dynamic material flow analysis, dynamic input-output (I/O) analysis, and life cycle assessment (LCA) and we merge these concepts into a common framework for modeling fixed capital stocks. We demonstrate the usefulness of the framework for simultaneous accounting of capital and material stocks and for consequential LCA. We apply the framework to design a demand-driven dynamic I/O model with dynamic capital stocks, and we synthesize both the marginal and attributional matrix of technical coefficients (A-matrix) from detailed process inventories of fixed assets of different age cohorts and technologies. The stock modeling framework allows researchers to identify and exploit synergies between different model families under the umbrella of socioeconomic metabolism.
Light-weighting of passenger cars using high-strength steel or aluminum is a common emissions mitigation strategy. We provide a first estimate of the global impact of light-weighting by material substitution on GHG emissions from passenger cars and the steel and aluminum industries until 2050. We develop a dynamic stock model of the global car fleet and combine it with a dynamic MFA of the associated steel, aluminum, and energy supply industries. We propose four scenarios for substitution of conventional steel with high-strength steel and aluminum at different rates over the period 2015-2050. We show that light-weighting of passenger cars can become a 'gigaton solution': Between 2015 and 2050, persistent light-weighting of passenger cars can, under optimal conditions, lead to cumulative GHG emissions savings of 9-18 gigatons CO2-eq. compared to development business-as-usual. Annual savings can be up to 1 gigaton per year. After 2030, enhanced material recycling can lead to further reductions: closed-loop metal recycling in the automotive sector may reduce cumulative emissions by another 4-6 gigatons CO2-eq. The effectiveness of emissions mitigation by material substitution significantly depends on how the recycling system evolves. At present, policies focusing on tailpipe emissions and life cycle assessments of individual cars do not consider this important effect.
The world supply and turnover of copper was modelled using simple empirical estimates and a COPPER systems dynamics model developed for this study. The model combines mining, trade markets, price mechanisms, population dynamics, use in society and waste as well as recycling, into a whole world system. The degree of sustainability and resource time horizon was estimated using four different methods including (1) burn-off rates, (2) peak discovery early warning, (3) Hubbert's production model, and (4) COPPER, a system dynamics model. The ultimately recoverable reserves (URR) have been estimated using different sources that converge around 2800 million tonne, where about 800 million tonne have already been mined, and 2000 million tonne remain. The different methods independently suggest peak copper mine production in the near future. The model was run for a longer period to cover all systems dynamics and delays. The peak production estimates are in a narrow window in time, from 2031 to 2042, with the best model estimate in 2034, or 21 years from the date of writing. In a longer perspective, taking into account price and recycling, the supply of copper to society is estimated to run out sometime after 2400. The outputs from all models put focus on the importance of copper recycling so that society can become more sustainable with respect to copper supply.
Aluminum recycling currently occurs in a cascading fashion, where some alloys, used in a limited number of applications, absorb most of the end-of-life scrap. An expected increase in scrap supply in coming decades necessitates restructuring of the aluminum cycle to open up new recycling paths for alloys and avoid a potential scrap surplus. This paper explores various interventions in end of life management and recycling of automotive aluminum, using a dynamic substance flow analysis model of aluminum and its alloying elements with resolution on component and alloy level (vehicle-component-alloy-element model). It was found that increased component dismantling before vehicle shredding can be an effective, so far underestimated, intervention in the medium term, especially if combined with development of safety-relevant components such as wheels from secondary material. In the long term, automatic alloy sorting technologies are most likely required, but could at the same time reduce the need for magnesium removal in refining. Cooperation between the primary and secondary aluminum industries, the automotive industry and end-of-life vehicle dismantlers is therefore essential to ensure continued recycling of automotive aluminum and its alloying elements.
A dynamic analysis of anthropogenic aluminum stocks and flows in the U.S. from 1900 to 2009 has been conducted. Key findings include (1) historical cumulative aluminum input into the U.S. anthroposphere amounts to 438 Tg, with only about 35% of it accumulating in domestic in-use stock; (2) less than 5% of most flows take place before 1950, while more than 50% of them happen after 1990; (3) flows into fabrication, manufacturing, and use processes, as well as trade flows, are vulnerable to energy crises; basically, after an energy crisis, the U.S. tends to produce less primary aluminum, less semis, as well as less final products, and therefore import less bauxite and alumina but import more unwrought aluminum and final products; (4) the U.S. has been a net importer of aluminum from the life cycle perspective, with its total annual net import increasing from 1945 to 2005; (5) as a result of the continuous increase of net import, total domestic stock of aluminum in the U.S. dramatically increases in the period of 1945–2009 and amounts to 316 Tg in 2009, about nine times of that in 1900; (6) in-use stock comprises about 48% of total domestic stock in 2009 and is dominated by two sectors, Buildings and Construction (32%) and Transportation (35%); (7) total per-capita stock in use of aluminum keeps increasing until 2009 and currently amounts to 490 kg; (8) per-capita stock of aluminum in Transportation sector increases substantially after 1990s because of the light-weighting of automobiles, while that in the Buildings and Construction and Electrical Engineering sectors seems have reached a saturation level after 2005.
Industrialization and urbanization in the developing world have boosted steel demand during the recent two decades. Reliable estimates on how much steel is required for high economic development are necessary to better understand the future challenges for employment, resource management, capacity planning, and climate change mitigation within the steel sector. During their use phase, steel-containing products provide service to people, and the size of the in-use stock of steel can serve as an indicator of the total service level. We apply dynamic material flow analysis to estimate in-use stocks of steel in about 200 countries and identify patterns of how stocks evolve over time. Three different models of the steel cycle are applied and a full uncertainty analysis is conducted to obtain reliable stock estimates for the period 1700–2008.Per capita in-use stocks in countries with a long industrial history, e.g., the U.S, the UK, or Germany, are between 11 and 16 tons, and stock accumulation is slowing down or has come to a halt. Stocks in countries that industrialized rather recently, such as South Korea or Portugal, are between 6 and 10 tons per capita and grow fast. In several countries, per capita in-use stocks of steel have saturated or are close to saturation. We identify the range of saturation to be 13 ± 2 tons for the total per capita stock, which includes 10 ± 2 tons for construction, 1.3 ± 0.5 tons for machinery, 1.5 ± 0.7 tons for transportation, and 0.6 ± 0.2 tons for appliances and containers. The time series for the stocks and the saturation levels can be used to estimate future steel production and scrap supply.
Material cycles have become increasingly coupled and interconnected in a globalizing era. While material flow analysis (MFA) has been widely used to characterize stocks and flows along technological life cycle within a specific geographical area, trade networks among individual cycles have remained largely unexplored. Here we developed a trade-linked multilevel MFA model to map the contemporary global journey of anthropogenic aluminum. We demonstrate that the anthropogenic aluminum cycle depends substantially on international trade of aluminum in all forms and becomes highly interconnected in nature. While the Southern hemisphere is the main primary resource supplier, aluminum production and consumption concentrate in the Northern hemisphere, where we also find the largest potential for recycling. The more developed countries tend to have a substantial and increasing presence throughout the stages after bauxite refining and possess highly consumption-based cycles, thus maintaining advantages both economically and environmentally. A small group of countries play a key role in the global redistribution of aluminum and in the connectivity of the network, which may render some countries vulnerable to supply disruption. The model provides potential insights to inform government and industry policies in resource criticality, supply chain security, value chain management, and cross-boundary environmental impacts mitigation.
According to industry statistics, the U.S. passed the peak in its rate of oil discovery about 1956, and the peak in its proved reserves at about the end of 1960. During the post-war period from 1945 to 1956, the number of new- field wildcat wells required to make one profitable oil or gas discovery increased from 26 to 52--a 50% reduction in the effectiveness of exploration efforts. The history of petroleum geology began with formulations of the anticlinal accumulation of oil by 3 different geologists as early as 1861--within 18 mo. after the Drake discovery. During the next half century this basic idea underwent many vicissitudes, because oil was found in a great variety of structural positions. The period of 1910-1935, which can be regarded as the ''Golden Age'' of petroleum geology, was a period of fundamental and provocative inquiry into basic questions of origin, migration, and entrapment of oil and gas. Then followed a period of stagnation based on the illusion that the answers to fundamental problems were known. As a consequence, the practice of petroleum geology degenerated into deadening routines of putting rock geometry on maps, and drilling the geometric highs. (45 refs.)
A systems dynamics model was developed to assess the planetary boundary for P supply in relation to use by human society. It is concluded that present day use rates and poor recycling rates of P are unsustainable at timescales beyond 100+a. The predictions made suggest that P will become a scarce and expensive material in the future. The study shows clearly that market mechanisms alone will not be able to secure an efficient use before a large part of the resource will have been allowed to dissipate into the natural environment. It is suggested that population size management and effective recycling measures must be planned long term to avoid unpleasant consequences of hunger and necessary corrections imposed on society by mass balance and thermodynamics.
Forecasts up to 2050 are made of consumption of the following metals: Fe, At, Cu, Mn, Zn, Cr, Ph, Ni, Si, Sn, rare earths, Me, Li, Sb, W, Ag, Co, In, An, Ga, Pt and Pd. The forecasts are based on the linear decoupling model of the relation between per capita metal consumption and per capita GDP. The models of each metal are applied to the economic development model of BRICs and G6 countries. According to these forecasts, the overall consumption of metals in 2050 will be five times greater than the current levels, and demand for metals, such as Au, Ag, Cu, Ni, Sn, Zn, Ph and Sb, is expected to be several times greater than the amount of their respective reserves. Demand for Fe and Pt, which is considered to be optimistic about the resource exhaustion, will also exceed the current reserves. Urgent measures are needed to find alternatives from common resources and to shift into sound materials circulation society.
A comprehensive annual cycle for stocks and flows of zinc, based on data from circa 1994 and incorporating information on extraction, processing, fabrication, use, discard, recycling, and landfilling, was carried out at three discrete governmental unit levels—54 countries and 1 country group (which together comprise essentially all global anthropogenic zinc stocks and flows), nine world regions, and the planet as a whole. All of these cycles are available in an electronic supplement to this article, which thus provides a metadata set on zinc flows for the use of industrial ecology researchers. A “best estimate” global zinc cycle was constructed to resolve aggregation discrepancies. Among the most interesting results are the following: (1) The accumulation ratio, that is, addition to in-use stock as a function of zinc entering use, is positive and large (2/3 of zinc entering use is added to stock) (country, regional, and global levels); (2) secondary input ratios (fractions of input to fabrication that are from recycled zinc) and domestic recycling percentages (fractions of discarded zinc that are recycled) differ among regions by as much as a factor of six (regional level); (3) worldwide, about 40% of the zinc that was discarded in various forms was recovered and reused or recycled (global level); (4) zinc cycles can usefully be characterized by a set of ratios, including, notably, the utilization efficiency (the ratio of manufacturing waste to manufacturing output: 0.090) and the prompt scrap ratio (new scrap as a fraction of manufacturing input: 0.070) (global level). Because capturable discards are a significant fraction of primary zinc inputs, if a larger proportion of discards were recaptured, extraction requirements would decrease significantly (global level). The results provide a framework for complementary studies in resource stocks, industrial resource utilization, energy consumption, waste management, industrial economics, and environmental impacts.
This paper dynamically analyzes the Japanese material flow of stainless steel. The substance flow analysis of Cr and Ni associated with stainless steel was conducted by classifying the material flow of stainless steel into two main alloy types: ferritic and austenitic. The substance flow covered more than 80% of Cr and Ni consumption in Japan. In mass balances of Cr and Ni, the production of not only stainless steel but also other alloying steels containing Cr and/or Ni was taken into account. The mass balances of three elements (Fe, Cr, and Ni) provided complementary information for confirmation of our estimations. As a result of dynamic analysis, the in-use stock of ferritics and austenitics at the end of the year 2005 was 4Tg and 14Tg, respectively, which converts to 3Tg of Cr and 1Tg of Ni. In addition, the recycling flow was closely analyzed. From the result for the year 2005, the recycling rates as stainless steel scrap were estimated as 21–38% for ferritics and 94–100% for austenitics. The amount of ferritics scrap to be recycled as carbon steel was quantified as well. By comparing our results with those in previous studies, we found that applying parameters obtained in other countries may be misleading, especially in recycling flows.
The rise of China to become world largest iron and steel producer and consumer since the late 1990s can be largely attributed to urbanization, with about 20% of China's steel output used by residential buildings, and about 50% for the construction sector as a whole. Previously, a dynamic material flow analysis (MFA) model was developed to analyze the dynamics of the rural and the urban housing systems in China. This model is expanded here to specifically analyze iron and steel demand and scrap availability from the housing sector. The evolution of China's housing stock and related steel is simulated from 1900 through 2100. For almost all scenarios, the simulation results indicate a strong drop in steel demand for new housing construction over the next decades, due to the expected lengthening of the – presently extremely short – life span of residential buildings. From an environmental as well as a resource conservation point of view, this is a reassuring conclusion. Calculations for the farther future indicate that the demand for steel will not just decrease but will rather oscillate: the longer the life spans of buildings, the stronger the oscillation. The downside of this development would be the overcapacities in steel production. A scenario with slightly lower life spans but a strong emphasis on secondary steel production might reduce the oscillation at moderate environmental costs.
An ``anthrobiogeochemical'' copper cycle, from Earth's core to the Moon,
combining natural biogeochemical and human anthropogenic stocks and
flows is derived for the mid-1990s. Although some aspects of the
quantification have moderate to high uncertainty, the anthropogenic
mining, manufacturing, and use flows (on the order of 104 Gg
Cu/yr) clearly dominate the cycle. In contrast, the natural repositories
of Earth's core, mantle, and crust, and of the Moon, hold much higher
stocks of copper (>1010 Gg) than do anthropogenic
repositories (<106 Gg). The results indicate that the
present anthropogenic rate of copper extraction exceeds the natural rate
of renewal by ~106.
We present a dynamic model of global copper stocks and flows which allows a detailed analysis of recycling efficiencies, copper stocks in use, and dissipated and landfilled copper. The model is based on historical mining and refined copper production data (1910-2010) enhanced by a unique data set of recent global semifinished goods production and copper end-use sectors provided by the copper industry. To enable the consistency of the simulated copper life cycle in terms of a closed mass balance, particularly the matching of recycled metal flows to reported historical annual production data, a method was developed to estimate the yearly global collection rates of end-of-life (postconsumer) scrap. Based on this method, we provide estimates of 8 different recycling indicators over time. The main indicator for the efficiency of global copper recycling from end-of-life (EoL) scrap-the EoL recycling rate-was estimated to be 45% on average, ± 5% (one standard deviation) due to uncertainty and variability over time in the period 2000-2010. As uncertainties of specific input data-mainly concerning assumptions on end-use lifetimes and their distribution-are high, a sensitivity analysis with regard to the effect of uncertainties in the input data on the calculated recycling indicators was performed. The sensitivity analysis included a stochastic (Monte Carlo) uncertainty evaluation with 10(5) simulation runs.
A dynamic material flow model was developed to simulate the evolution of global aluminum stocks in geological reserve and anthropogenic reservoir from 1900 to 2010 on a country level. The contemporary global aluminum stock in use (0.6 Gt or 90 kg/capita) has reached about 10% of that in known bauxite reserves and represents an embodied energy amount that is equivalent to three quarters of the present global annual electricity consumption. The largest proportions of in-use stock are located in the U.S. (28%), China (15%), Japan (7%), and Germany (6%) and in sectors of building and construction (40%) and transportation (27%). Industrialized countries have shown similar patterns of aluminum in-use stock growth: once the per-capita stocks have reached a threshold level of 50 kg, they kept a near linear annual growth of 5-10 kg/capita; no clear signs of saturation can be observed yet. The present aluminum in-use stocks vary widely across countries: approximately 100-600 kg/capita in industrialized countries and below 100 kg/capita in developing countries. The growing global aluminum in-use stock has significant implications on future aluminum demand and provides important recycling opportunities that will be critical for greenhouse gas emissions mitigation in the aluminum industry in the coming decades.
The stocks and flows of the global silver, aluminum, chromium, copper,
iron, nickel, lead, and zinc cycles quantify over 98% of the total mass
of metal mobilized by human activity at the turn of the 21st century.
Iron and aluminum, representing >95% by mass of all metals mined, are
for the first time assessed for global anthropogenic emissions to air,
water, and land. Anthropogenic activity has significantly perturbed
Earth's natural biogeochemical cycles, attested by the "grand nutrient"
cycles of carbon, nitrogen, phosphorous, and sulfur and further revealed
here by the "anthrobiogeochemical" cycles of metals. We demonstrate that
humans today mobilize about half the metal mass of these global
elemental metal cycles.
