Global Rare Earth In‐Use Stocks in NdFeB Permanent Magnets

The rare earth elements are indispensible in modern technology, especially in the applications of permanent magnets. Very little quantitative information is available on rare earth elements used in permanent magnets, however. This study looks back to 1983, when neodymium‐iron‐boron (NdFeB) permanent magnets were first manufactured, and reaches to 2007, when the market of permanent magnets was well developed. We draw on the historical data on permanent magnets from China, Japan, the United States, and Europe to provide the first estimates of global in‐use stocks for four rare earth elements—praseodymium (Pr), neodymium (Nd), terbium (Tb), and dysprosium (Dy)—in NdFeB permanent magnets. In‐use stocks amount to 62.6 gigagrams (Gg) Nd, 15.7 Gg Pr, 15.7 Gg Dy, and 3.1 Gg Tb; these stocks, if efficiently recycled, could provide a valuable supplement to geological stocks as they are almost four times the 2007 annual extraction rate of the individual elements.     

Static material flow analysis of neodymium in China

Neodymium is one of the most important enabling materials for next‐generation clean technologies, especially electric vehicles and wind turbines. As the world's largest producer of rare earth minerals, China dominates the global neodymium supply and a considerable amount of primary neodymium resources are from illegal mining. Many studies have been conducted on the material flow of neodymium in different regions, but few studies focus on China. In this study, a static material flow analysis of neodymium is conducted to quantitatively analyze the industrial chain structure of neodymium in China and to calculate the neodymium output from illegal mining. The results quantitatively depict the neodymium material flow of each stage of China's neodymium industrial chain in 2016, which indicates that 12.3–17.0 kt of primary neodymium resources were from illegal mining. On the basis of the results, reasonable conclusions can be drawn that the recycling of neodymium from end‐of‐life products provides an important opportunity to both reduce illegal rare earth mining and cope with increasing neodymium demand.     

Original Equipment Manufacturers’ Participation in Take‐Back Initiatives in Brazil

Lax legislation and increasing demand for electronics are driving relentless growth in electronic waste (e‐waste) in the developing world. To reduce the damage caused by e‐waste and recover value from end‐of‐life (EoL) electronics, original equipment manufacturers (OEMs) have created, over the past decades, programs to divert e‐waste from landfills to recycling and reuse. Although the subject of intense debate, little is known about such initiatives in terms of levels of participation by OEMs or the extent to which they have succeeded in reducing e‐waste in developing economies. To broaden our understanding of these issues, we investigate take‐back initiatives in the thriving market of personal computers (i.e., desktop and laptop computers) in Brazil. Using a multimethod approach (electronic archival data collection and semistructured interviews with manufacturers), we find evidence that large multinational manufacturers are at the forefront of take‐back programs. However, these initiatives in many ways lag behind those implemented in the United States, a more developed market as far as product take‐back is concerned. We find the main reasons for the low levels of participation by OEMs in take‐back programs to be high collection costs, low residual values, and lax, unclear, and conflicting legislation. Moreover, we propose new avenues of research, in light of our scant knowledge of country‐specific, company‐specific, and product‐specific determinants that moderate participation.     

Evaluation of Modeling Approaches to Determine End‐of‐Life Flows Associated with Buildings: A Viennese Case Study on Wood and Contaminants

Dynamic material flow analysis enables the forecasting of secondary raw material potential for waste volumes in future periods, by assessing past, present, and future stocks and flows of materials in the anthroposphere. Analyses of waste streams of buildings stocks are uncertain with respect to data and model structure. Wood construction in Viennese buildings serve as a case study to compare different modeling approaches for determining end‐of‐life (EoL) wood and corresponding contaminant flows (lead, chlorine, and polycyclic aromatic hydrocarbons). A delayed input and a leaching stock modeling approach are used to determine wood stocks and flows from 1950 until 2100. Cross‐checking with independent estimates and sensitivity analyses are used to evaluate the results’ plausibility. In the situation of the given data in the present case study, the delay approach is a better choice for historical observations of EoL wood and for analyses at a substance level. It has some major drawbacks for future predictions at the goods level, though, as the durability of a large number of historical buildings with considerably higher wood content is not reflected in the model. The wood content parameter differs strongly for the building periods and has therefore the highest influence on the results. Based on this knowledge, general recommendations can be derived for analyses on waste flows of buildings at a goods and substance level.     

End-of-life modelling in life cycle assessment—material or product-centred perspective?

Purpose

End-of-life (EoL) modelling in life cycle assessment has already been broadly discussed within several studies. However, no consensus has been achieved on how to model recycling in LCA, even though several approaches have been developed. Within this paper, results arising from the application of two new EoL formulas, the product environmental footprint (PEF) and the multi-recycling-approach (MRA) ones, are compared and discussed. Both formulas consider multiple EoL scenarios such as recycling, incineration and landfill.

Methods

The PEF formula has been developed within the PEF programme whose intent is to define a harmonized methodology to evaluate the environmental performance of products. The formula is based on a 50:50 allocation approach, as burdens and benefits associated with recycling are accounted for a 50% rate. The MRA formula has been developed to change focus from products to materials. Recycling cycles and material losses over time are considered with reference to material pools. Allocation between systems is no longer needed, as the actual number of potential life cycles for a certain material is included in the calculation. Both the approaches have been tested within two case studies.

Results and discussion

Methodological differences could thereof be determined, as well as applicability concerns, due to the type of data required for each formula. As far as the environmental performance is concerned, impacts delivered by MRA are lower than those delivered by PEF for aluminium, while the opposite happens for plastic and rubber due to the higher share of energy recovery accounted in PEF formula. Stainless steel impacts are almost the same.

Conclusions and recommendations

The application of the two formulas provides some inputs for the EoL dilemma in LCA. The use of a wider perspective, better reflecting material properties all over the material life cycle, is of substantial importance to properly represent recycling situations. In MRA, such properties are treated and less data are required compared to the PEF formula. On the contrary, the PEF model better accommodates the modelling of products whose materials, at end of life, can undertake the route of recycling or recovery (or landfill), depending on country-specific EoL management practices. However, its application requires more data.

     

Mapping first to final uses for rare earth elements,globally and in the United States

Estimating the material flows of rare earth elements (REEs) is essential to understanding which industries are most vulnerable to potential REE supply disruptions which, in turn, may inform policy recommendations aimed at reducing the supply risk. However, the REEs are a group of mineral commodities characterized by highly uncertain estimates of supply and demand due to the REE market's complexity, opacity, and small size. In this study, a streamlined methodology was applied to map mineral commodity first-use to final-use applications and to estimate total requirements at the national level based on available industrial data for final-use finished goods. This analysis examines REEs both as a group and individually, showing that total US requirements are between 15% and 16.5% of world requirements for the year 2015, the latest year with the most complete information available. The findings shed light on US industrial capabilities by revealing the discrepancy between the types of REEs that go into US raw material consumption and those that are contained in embedded consumption. For instance, given the United States’ large oil refining industry, US raw material consumption of lanthanum is quite high. In contrast, US raw material consumption of neodymium is relatively low, whereas embedded demand is comparatively high. This reflects the lack of industrial capacity to process REE concentrates into magnet material combined with the US's high imports of products that contain rare earth permanent magnets.     

Decomposition of Toxic Chemical Substance Management in Three U.S. Manufacturing Sectors from 1991 to 2008

This study analyzes toxic chemical substance management in three U.S. manufacturing sectors from 1991 to 2008. Decomposition analysis applying the logarithmic mean Divisia index is used to analyze changes in toxic chemical substance emissions by the following five factors: cleaner production, end‐of‐pipe treatment, transfer for further management, mixing of intermediate materials, and production scale. Based on our results, the chemical manufacturing sector reduced toxic chemical substance emissions mainly via end‐of‐pipe treatment. In the meantime, transfer for further management contributed to the reduction of toxic chemical substance emissions in the metal fabrication industry. This occurred because the environmental business market expanded in the 1990s, and the infrastructure for the recycling of metal and other wastes became more efficient. Cleaner production is the main contributor to toxic chemical reduction in the electrical product industry. This implies that the electrical product industry is successful in developing a more environmentally friendly product design and production process.     

Unintentional Flow of Alloying Elements in Steel during Recycling of End‐of‐Life Vehicles

Alloying elements in steel add a wide range of valuable properties to steel materials that are indispensable for the global economy. However, they are likely to be effectively irretrievably blended into the steel when recycled because of (among other issues) the lack of information about the composition of the scrap. This results in the alloying elements dissipating in slag during steelmaking and/or becoming contaminants in secondary steel. We used the waste input‐output material flow analysis model to quantify the unintentional flows of alloying elements (i.e., chromium, nickel, and molybdenum) that occur in steel materials and that result from mixing during end‐of‐life (EOL) processes. The model can be used to predict in detail the flows of ferrous materials in various phases, including the recycling phase by extending steel, alloying element source, and iron and steel scrap sectors. Application of the model to Japanese data indicates the critical importance of the recycling of EOL vehicles (ELVs) in Japan because passenger cars are the final destination of the largest share of these alloying elements. However, the contents of alloying elements are rarely considered in current ELV recycling. Consequently, the present study demonstrates that considerable amounts of alloying elements, which correspond to 7% to 8% of the annual consumption in electric arc furnace (EAF) steelmaking, are unintentionally introduced into EAFs. This result suggests the importance of quality‐based scrap recycling for efficient management of alloying elements.     

Life Cycle Assessment of Novel Aircraft Interior Panels Made from Renewable or Recyclable Polymers with Natural Fiber Reinforcements and Non‐Halogenated Flame Retardants

A comprehensive life cycle assessment of panels for aircraft interiors was conducted, including both a conventional glass fiber‐reinforced panel and different novel sustainable panels. The conventional panel is made of a glass fiber‐reinforced thermoset composite with halogenated flame retardant, whereas the sustainable panels are made of renewable or recyclable polymers, natural fiber reinforcements, and nonhalogenated flame retardants. Four different sustainable panels were investigated: a geopolymer‐based panel; a linseed‐oil–based biopolymer panel; and two thermoplastic panels, one with polypropylene (PP) and another with polylactic acid (PLA). All of the sustainable panels were developed to fulfil fire resistance requirements and to be lighter than the conventional panels in order to reduce fuel consumption and air pollutant emissions from the aircraft. The environmental impacts associated with energy consumption and air emissions were assessed, as well as other environmental impacts resulting from the extraction and processing of materials, transportation of materials and waste, panel manufacturing, use, maintenance, and end of life (EoL). All the sustainable panels showed better environmental performance than the conventional panel. The overall impacts of the sustainable panels were offset by the environmental benefits in the use stage attributed to weight reduction. One square meter of the novel panels could save to 6,000 kilograms of carbon dioxide equivalents. The break‐even point (in months) at which the use of sustainable panels would yield an environmental benefit relative to the impacts arising in production and EoL was as follows: 1.2 for the geopolymer panel; 1.7 for the biopolymer panel; 10.4 for the PLA panel; and 54.5 for the PP panel.     

What Do We Know About Metal Recycling Rates?

The recycling of metals is widely viewed as a fruitful sustainability strategy, but little information is available on the degree to which recycling is actually taking place. This article provides an overview on the current knowledge of recycling rates for 60 metals. We propose various recycling metrics, discuss relevant aspects of recycling processes, and present current estimates on global end‐of‐life recycling rates (EOL‐RR; i.e., the percentage of a metal in discards that is actually recycled), recycled content (RC), and old scrap ratios (OSRs; i.e., the share of old scrap in the total scrap flow). Because of increases in metal use over time and long metal in‐use lifetimes, many RC values are low and will remain so for the foreseeable future. Because of relatively low efficiencies in the collection and processing of most discarded products, inherent limitations in recycling processes, and the fact that primary material is often relatively abundant and low‐cost (which thereby keeps down the price of scrap), many EOL‐RRs are very low: Only for 18 metals (silver, aluminum, gold, cobalt, chromium, copper, iron, manganese, niobium, nickel, lead, palladium, platinum, rhenium, rhodium, tin, titanium, and zinc) is the EOL‐RR above 50% at present. Only for niobium, lead, and ruthenium is the RC above 50%, although 16 metals are in the 25% to 50% range. Thirteen metals have an OSR greater than 50%. These estimates may be used in considerations of whether recycling efficiencies can be improved; which metric could best encourage improved effectiveness in recycling; and an improved understanding of the dependence of recycling on economics, technology, and other factors.     

Prospective Impacts of Electronic Textiles on Recycling and Disposal

Electronic textiles are a vanguard of an emerging generation of smart products. They consist of small electronic devices that are seamlessly embedded into clothing and technical textiles. E‐textiles provide enhanced functions in a variety of unobtrusive and convenient ways. Like many high‐tech products, e‐textiles may evolve to become a mass market in the future. In this case, large amounts of difficult‐to‐recycle products will be discarded. That can result in new waste problems. This article examines the possible end‐of‐life implications of textile‐integrated electronic waste. As a basis for assessment, the innovation trends of e‐textiles are reviewed, and an overview of their material composition is provided. Next, scenarios are developed to estimate the magnitude of future e‐textile waste streams. On that base, established disposal and recycling routes for e‐waste and old textiles are assessed in regard to their capabilities to process a blended feedstock of electronic and textile materials. The results suggest that recycling old e‐textiles will be difficult because valuable materials are dispersed in large amounts of heterogeneous textile waste. Moreover, the electronic components can act as contaminants in the recycling of textile materials. We recommend scrutinizing the innovation trend of technological convergence from the life cycle perspective. Technology developers and product designers should implement waste preventative measures at the early phases in the development process of the emerging technology.     

Biosynthesis of chain‐specific alkanes by metabolic engineering in Escherichia coli

Renewable energy is one of the key issues for sustainable development. Compared with alcohols and esters, alkanes—with the highest energy density—are a better liquid fuel. In this study, we focused on medium‐chain alkanes, the main compounds of jet fuels. To control the chain length of alkanes, a chain length specific thioesterase from Umbellularia californica, a fatty acyl‐CoA reductase Acinetobacter sp. M‐1 that prefers lauroyl‐CoA and myristoyl‐CoA, and a decarbonylase from Nostoc punctiforme were engineering into Escherichia coli cells. The combination of genes, which determines the chain length of products, was carefully designed to control the product spectrum. Undecane and tridecane were produced with a concentration of 2.21 ± 0.18 and 1.83 ± 0.12 mg?g^?1, respectively. A total of 4.01 ± 0.43 mg?g^?1 pentadecane was also detected in the final products. The results showed the feasibility to use microorganisms as cell factories for alkane production. The product spectrum revealed that the chosen genes played a key role in the production of chain length specific alkanes.     

Life cycle assessment of construction materials: the influence of assumptions in end-of-life modelling

Purpose

The nature of end-of-life (EoL) processes is highly uncertain for constructions built today. This uncertainty is often neglected in life cycle assessments (LCAs) of construction materials. This paper tests how EoL assumptions influence LCA comparisons of two alternative roof construction elements: glue-laminated wooden beams and steel frames. The assumptions tested include the type of technology and the use of attributional or consequential modelling approaches.

Methods

The study covers impact categories often considered in the construction industry: total and non-renewable primary energy demand, water depletion, global warming, eutrophication and photo-chemical oxidant creation. The following elements of the EoL processes are tested: energy source used in demolition, fuel type used for transportation to the disposal site, means of disposal and method for handling allocation problems of the EoL modelling. Two assumptions regarding technology development are tested: no development from today’s technologies and that today’s low-impact technologies have become representative for the average future technologies. For allocating environmental impacts of the waste handling to by-products (heat or recycled material), an attributional cut-off approach is compared with a consequential substitution approach. A scenario excluding all EoL processes is also considered.

Results and discussion

In all comparable scenarios, glulam beams have clear environmental benefits compared to steel frames, except for in a scenario in which steel frames are recycled and today’s average steel production is substituted, in which impacts are similar. The choice of methodological approach (attributional, consequential or fully disregarding EoL processes) does not seem to influence the relative performance of the compared construction elements. In absolute terms, four factors are shown to be critical for the results: whether EoL phases are considered at all, whether recycling or incineration is assumed in the disposal of glulam beams, whether a consequential or attributional approach is used in modelling the disposal processes and whether today’s average technology or a low-impact technology is assumed for the substituted technology.

Conclusions

The results suggest that EoL assumptions can be highly important for LCA comparisons of construction materials, particularly in absolute terms. Therefore, we recommend that EoL uncertainties are taken into consideration in any LCA of long-lived products. For the studied product type, LCA practitioners should particularly consider EoL assumptions regarding the means of disposal, the expected technology development of disposal processes and any substituted technology and the choice between attributional and consequential approaches.     

An Urban Metabolism and Carbon Footprint Analysis of the Jing–Jin–Ji Regional Agglomeration

Urban energy metabolism includes processes for exploiting, transforming, and consuming energy, as well as processes for recycling by‐products and wastes. Embodied energy is the energy consumed during all of these activities, both directly and indirectly. Multiregional input‐output (MRIO) analysis can calculate the energy consumption embodied in flows among sectors for multiple cities or regions. Our goal was to address a problem apparent in previous research, which was insufficient attention to indirect energy flows. We combined MRIO analysis with ecological network analysis to calculate the embodied energy consumption and the energy‐related carbon footprints of five sectors in three regions that comprise the Jing‐Jin‐Ji agglomeration, using data from 2002 and 2007. Our analysis traced metabolic processes of sectors from the perspective of final consumption. Based on the embodied energy analysis, we quantified the indirect energy consumption implied in exchanges of sectors and its distribution and identified the relationships formed through the indirect consumption to analyze the roles of providers and receivers in the system. Results showed that the embodied energy consumption for the Jing‐Jin‐Ji region increased from 2002 to 2007 as a result of increased energy consumption in Tianjin and Hebei. Overall, consumption of Beijing decreased likely attributable to the fact that government policies relocated industries during this time in anticipation of the Olympic Games. The relationships among sectors changed: Beijing changed from a net exporter to an importer, whereas Hebei changed from a net importer of energy from Beijing to an exporter to Beijing, and Tianjin served as an importer in both years.     

Economic Feasibility of Recycling Photovoltaic Modules

The market for photovoltaic (PV) electricity generation has boomed over the last decade, and its expansion is expected to continue with the development of new technologies. Taking into consideration the usage of valuable resources and the generation of emissions in the life cycle of photovoltaic technologies dictates proactive planning for a sound PV recycling infrastructure to ensure its sustainability. PV is expected to be a “green” technology, and properly planning for recycling will offer the opportunity to make it a “double‐green” technology—that is, enhancing life cycle environmental quality. In addition, economic feasibility and a sufficient level of value‐added opportunity must be ensured, to stimulate a recycling industry. In this article, we survey mathematical models of the infrastructure of recycling processes of other products and identify the challenges for setting up an efficient one for PV. Then we present an operational model for an actual recycling process of a thin‐film PV technology. We found that for the case examined with our model, some of the scenarios indicate profitable recycling, whereas in other scenarios it is unprofitable. Scenario SC4, which represents the most favorable scenario by considering the lower bounds of all costs and the upper bound of all revenues, produces a monthly profit of $107,000, whereas the least favorable scenario incurs a monthly loss of $151,000. Our intent is to extend the model as a foundation for developing a framework for building a generalized model for current‐PV and future‐PV technologies.     

Effects of neodymium magneto-priming on seed germination and salinity tolerance in tomato

Earth's biosphere is surrounded by magnetic fields that affect all living organisms. A plant's response to magnetic fields is displayed in terms of its seed's vigor, growth, and yield. Examining seed germination in such magnetic fields is the first step in the investigation of how magnetic fields might be used to enhance plant growth and maximize crop performance. In this study, salinity-sensitive Super Strain-B tomato seeds were primed with the northern and southern poles of neodymium magnets of 150, 200, and 250 mT. The magneto-primed seeds showed a significant increase in germination rate and speed, where the orientation of the magnet was identified as being crucial for germination rate and the orientation of seeds towards the magnet was shown to affect the germination speed. The primed plants exhibited enhanced growth characteristics, including longer shoots and roots, larger leaf area, more root hairs, higher water content, and more tolerance to salinity levels, up to 200 mM NaCl. All magneto-primed plants showed a significant decrease in chlorophyll content, continuous chlorophyll fluorescence yield (Ft), and quantum yield (QY). The salinity treatments decreased all chlorophyll parameters in control plants, significantly, but did not lower such parameters in magneto-primed tomatoes. The results of this study illustrate the positive effects of neodymium magnet on the growth and development of tomato plants in terms of their germination, growth, and salinity tolerance, and negatively affected the chlorophyll content in tomato leaves. © 2023 Bioelectromagnetics Society.     

Assessing the Greenhouse Gas Savings Potential of Extended Producer Responsibility for Mattresses and Boxsprings in the United States

Extended producer responsibility (EPR) legislation in the United States, which currently only exists on the state level, now includes three mattress EPR acts, which intend to shift the financial and operational burden of mattress end‐of‐life (EOL) management away from local and state government. It is important to keep in mind, however, that the original objective behind EPR is to reduce the environmental life cycle impacts of products. This article therefore quantifies the greenhouse gas (GHG) savings potential of mattress and boxspring recycling and reuse in the United States and also discusses labor implications and mattress design issues. We find that all three acts are unlikely to generate redesign incentives, but are expected to dramatically increase mattress collection and recycling. The collection and recycling of all 35 million EOL mattress and boxspring units estimated to reach the end of their lives in the United States every year would generate in the order of 10,000 jobs and GHG savings between 1 and 1.5 million metric tonnes.