Virgin Production Research Articles

Comparative Life Cycle Assessment and Life Cycle Cost Analysis of Bonded Nd-Fe-B Magnets: Virgin Production versus Recycling

Comparative Life Cycle Assessment and Life Cycle Cost Analysis of Bonded Nd-Fe-B Magnets: Virgin Production versus Recycling

Measurement of thermal conductivity of thermally reactive materials for use in pyrolysis models

AbstractPyrolysis models are used in the fire science field to simulate the thermal decomposition of materials. These models require knowledge of the kinetic and thermodynamic parameters of an assumed reaction mechanism, and the thermophysical properties of the virgin material and product species. Standard test methods exist for measuring the thermal conductivity of nonreactive materials, but to date no suitable method exists that is compatible with contemporary pyrolysis models and is applicable to thermally reactive materials. In the present study, a modified methodology was presented and evaluated to address this need. The methodology involves a preliminary assessment of thermal stability, followed by a series of tests including: thermogravimetric analysis, differential scanning calorimetry, and laser flash analysis. Once a reaction mechanism has been identified, gram‐scale samples of the virgin and stable product species are isolated and independent measurements of thermal conductivity of those species are obtained. The methodology was applied to eucalyptus fiber hardboard, for which a complete set of property data for pyrolysis modeling was obtained. A pyrolysis experiment was then conducted, and that experiment was simulated using a pyrolysis model parameterized with the measured property data. Model predictions of the mass loss rate and temperature rise of a hardboard sample exposed to radiant heat flux of 35 and 60 kW m−2 were found to be a good match to measurements. These results demonstrate the suitability of the property data, the pyrolysis model, and the utility of this approach. This work will serve as a basis for property determination in future pyrolysis studies.

Life cycle assessment of alternatives for industrial textile recycling

The $882 billion textile trade in 2021 poses environmental concerns, highlighting the importance of encouraging a circular economy to attain sustainable textiles. Therefore, policies must prioritize textile recycling, particularly in developing countries, and sharing information throughout the value chain. This research aims to explore the potential environmental benefits of two industrial recycling processes for textile residues versus the traditional waste management and production process through a life cycle assessment applying the ReCiPe method at midpoint and endpoint levels focusing on generating significant data availability and broader assessment than existing literature to support decision making related to recycling systems for textile residues. Results related to the textile residues recycling process to obtain stripes (R1) and replace sawdust, to fill pushing balls, show that it would produce environmental benefits regardless of location in several midpoint categories. Furthermore, regarding the endpoint results, the DALY savings are mainly due to avoiding landfill, while the savings in ecosystem impacts are generated by avoiding landfill and sawdust production. Regarding the recycling process to obtain recycled yarn and fill (R2) net savings in global warming potential are generated if landfill avoidance is considered. Nevertheless, endpoint results show that DALYs of all the avoided processes correspond to 1.5 times the impacts of all the R2 recycling processes, mainly due to avoiding virgin yarn production. Therefore, both recycling processes are recommended. However, some strategies are required to generate greater benefits, such as applying the R2 recycling process as the first option for stretchable textile waste, and after being used, going through the R1 recycling process. In addition, the strategic placement of the R1 recycling facility should be distant from areas of sawdust production. A sensitivity analysis was carried out due to the variability of virgin products to replace in the market.

The Circularity of Materials from the Perspective of the Product Life Cycle: A Case Study of Secondary Fence Board, Part 2 (Scenario Analysis)

Recycling strategies demonstrate different life cycle environmental performance. In order to assess this performance, a life cycle assessment may be used. In such studies, the recycling should be linked with multifunctionality and allocation. This requires it to be modelled accordingly, especially in terms of environmental burdens and credits. The paper presents a case study of open-loop recycling. A flow of mixed post-consumer multi-material waste was reprocessed into another product with a new application—a fence board made of recycled material (secondary fence board). Although many allocation-related case studies are provided in the literature, no example of a comparison between different substitution scenarios for open-loop recycling has been found. In order to fill the gap, various hypothetical market-mix-based alternatives related to the virgin production and durability of products have been examined. The goal of the study is to assess the potential environmental impact of 1 m2 of secondary fence board modelled in different substitution scenarios. The paper is the second part of a two-part study. In Part 1, life cycle assessment results were presented for a baseline scenario (1A). Part 2 focuses strongly on allocation considerations. In order to ensure a consistency between the results of Part 1 and Part 2, the entire life cycle of the fence board has been taken into account in both calculations. The case study has shown that the results may be highly sensitive to the choice of substitutes and the choice of quality attributes impacting the reference flows (in our example, the durability of products).

Process simulation and life cycle assessment of hydrometallurgical recycling routes of waste printed circuit boards

Electronic waste remains a pressing global environmental concern. Addressing the proper treatment and recycling of waste printed circuit boards (WPCBs) is imperative to mitigate environmental pollution and prevent the loss of valuable resources. In this study, a comparative analysis of acidic and alkaline leaching processes for recovering base metals (Cu, Sn, Zn, and Ni) from WPCBs was conducted by process simulation (using HSC software). Life cycle inventories were compiled accordingly. Furthermore, by incorporating an alternative method for precious metal recovery, the life cycles (using openLCA software) of both processes for recovering all metals were examined. The results revealed that while the acidic leaching process showed higher recoveries for base metals and advantages in terms of lower electricity consumption and wastewater generation, it also exhibited a more pronounced environmental impact due to the chemical input in the HNO3 leaching process. Conversely, the alkaline leaching process utilized fewer chemicals, generated less solid waste and off-gases, resulting in a lower overall environmental impact. For recycling 1 t of WPCBs, the acidic leaching process achieved recoveries of 92% for tin, 99% for copper, 79% for zinc, and 94% for nickel, whereas the alkaline leaching process yielded recoveries of 96%, 93%, 78%, and 74% for the corresponding metals. Notably, the alkaline leaching process demonstrated a lower global warming potential of 11,395 kg CO2 eq, compared to the 12,459 kg CO2 eq associated with the acidic leaching process. In the evaluation of the alkaline leaching process, most environmental impacts were found to be lower than for virgin production. As a result, while the acidic leaching process is indeed more efficient in metal recycling, the alkaline leaching process emerges as a stronger contender in terms of environmental sustainability, with great potential for further technical improvements.

Direct recycling of spent nickel-rich cathodes in reciprocal ternary molten salts

Lithium-ion batteries (LIBs) have revolutionized portable electronics and electric vehicles (EVs), but the growing accumulation of end-of-life (EOL) batteries poses environmental challenges. Recycling high-value cathodes from EOL LIBs can minimize waste and reduce the need for mining critical minerals. This study focuses on the direct recycling of Ni-rich cathodes, particularly lithium-manganese-cobalt-oxide (NMC) 622 in a “reciprocal ternary molten salts (RTMS)" system. The ionothermal relithiation in the RTMS system successfully restores the layered structure, lithium content, and electrochemical performance of the NMC 622 cathode, comparable to the pristine material. The cost analysis reveals that cathode regeneration through ionothermal relithiation is more economical than virgin production or conventional recycling methods.

Material recycling in a circular economy—A systems view

AbstractA circular economy is expected to reduce the use of primary resources through the reuse of products, components, and materials. Material recycling, though advantageous in many cases for saving primary resources by diverting them away from the landfill, may have perverse effects when analyzed from a systems perspective considering the entire material life cycle as well as economy‐wide effects of recycling. Using the case of metals, glass, and plastics recycling, the advantages of a systems view including the entire material life cycle in analyzing material recycling are illustrated. The advantages of recycling as compared to virgin production may vary significantly depending of the energy and resource requirements during the recycling process, logistics, and alloying of materials. Expanding the systems view further to analyze the economy‐wide effects of material recycling reveal the possibility of rebound effects which may reduce or even negate its advantages. Sustainable consumption is absolutely essential along with any technological advances to counter the rebound effects that may lead to overshoot. The article demonstrates the importance of considering a systems view incorporating a life cycle perspective and economy‐wide effects in analyzing and trying to maintain the advantages of material recycling.This article is categorized under: Climate and Environment > Circular Economy Emerging Technologies > Materials Climate and Environment > Pollution Prevention

Environmental Impact Assessment of the Dismantled Battery: Case Study of a Power Lead–Acid Battery Factory in China

With the increase in battery usage and the decommissioning of waste power batteries (WPBs), WPB treatment has become increasingly important. However, there is little knowledge of systems and norms regarding the performance of WPB dismantling treatments, although such facilities and factories are being built across the globe. In this paper, environmental performance is investigated quantitively using life cycle assessment (LCA) methodology for a dismantled WPB manufacturing process in Tongliao city of Inner Mongolia Province, China. The functional unit was selected to be one metric ton of processed WPB, and the average data of 2021 were used. The results indicated that WPB dismantling treatments are generally sustainable in their environmental impacts, because the life cycle environmental effects can be neutralized by the substitution of virgin products with recycled counterparts. Of all the processes of dismantlement, Crude Lead Making, Refining, and Preliminary Desulfurization, were the top three contributors to the total environmental burden. The results of the sensitivity analysis showed that increasing photovoltaic power, wind power, and natural gas usage may significantly reduce the burden on the environment. On the basis of our findings, some suggestions are put forward for a policy to promote environmental green growth of WPB treatment. Although this paper is aimed at the power lead–acid battery, the research method is also of significance for the power lithium-ion battery, and we will conduct relevant research on the disassembly process of the power lithium-ion battery in the future.

Effect of the multiple injection process on the structural and mechanical properties of PP impact copolymers focusing on the deformation of ethylene-propylene copolymer

The influence of multiple injection on the structural and mechanical properties of PP impact copolymers (ICP) has been investigated, mainly focusing on the deformation of dispersed ethylene-propylene copolymer (EPC) particles in ICPs. Various properties of recycled ICPs throughout repetitive injection processes have been compared. The thermo-mechanical degradation by heat and shear stress imposed on ICPs several times via multiple injection triggered chemical changes, such as the generation of CC and CO bonds and chain scission in ICPs. These changes alter the crystallinity of the ICPs by shortening the chain length and narrowing the molecular weight distribution. To determine the effect of multiple injection on the deformation of EPC particles, the intrinsic viscosities (IV) of the polypropylene (PP) matrix and dispersed EPC were measured. Degradation by multiple injection was greater for PP than for EPC, thereby increasing the viscosity ratio (IVEPC/IVPP). At a high viscosity ratio, the PP matrix could not effectively transfer shear stress to the dispersed EPC particles, causing the EPC particles to agglomerate and become larger with poor dispersity. Regarding the mechanical properties, the agglomeration of EPC exerted a significant negative effect on the Izod impact strength. Finally, numerical calculations in the injection mold flow region confirmed that the re-injected product required a higher shear stress than the virgin product.

When does upcycling mitigate climate change? The case of wet spent grains and fruit and vegetable residues in Canada

AbstractWe investigate when upcycling—defined as treating food by‐products for human consumption—mitigates climate change. Earlier research only modeled pilot‐scale upcycling experiments, which discount its real‐world complexity. To tackle this important limitation, our research involved 130 interviews, life cycle assessment, and a simulation to assess what operational structures made upcycling environmentally sustainable and superior to alternatives such as animal feeding, anaerobic digestion, composting, and landfilling. We considered wet spent grains and fruit and vegetable residues in Canada, two important streams of unavoidable residuals in Western food systems. First, we found that the simulated range of greenhouse gas impacts, +938 to −465 kg of CO2 eq. emissions per tonne of upcycled material, was more optimistic than the ranges available in the literature. No previous estimates existed for the range of impacts for real cases, −18 and −300 kg of CO2 eq. emissions per tonne of upcycled material. Second, net‐negative carbon impacts were achieved only by operational structures with a technological configuration characterized by a total energy consumption lower than 1500 kWh per tonne of upcycled materials and a geographical scale inferior to 260 km (from point of collection to point of sale). Most of the real cases identified during our fieldwork matched these operational prescriptions and achieved a carbon footprint up to 25% smaller than the carbon footprint of the substituted virgin products. Third, our analysis of both best‐case simulated performance and real performance suggested that the positive carbon impact of upcycling was roughly comparable with that produced by animal feeding and anaerobic digestion, but superior to composting and landfilling. Our study illuminates the anatomy of environmentally sustainable upcycling operations and problematizes emergent food recovery hierarchies.

Molten salt electrolysis and room temperature ionic liquid electrochemical processes for refining rare earth metals: Environmental and economic performance comparison

Circularizing end of life products such as electronic waste can open a new source for rare earth elements (REEs) that will decrease the demand pressure on conventional virgin production. The last step to produce REEs consists of a refining process to convert rare earth oxide (REO) to REE metal. One promising technology is processing REO via a room temperature ionic liquid, which is characterized by low energy requirements in contrast to existing REEs extraction processes. In this work, life cycle and techno-economic assessments are performed and compared against molten salt electrolysis. The results show that both processes have advantages and disadvantages in terms of environmental performance, and that they are similarly competitive in terms of economic performance. A breakeven analysis suggests that future research should focus on coupling the production of REOs with the refining processes to attempt to lower REO cost and make them economically feasible in the U.S.

Evaluating ‘reuse’ in the current LCA framework – Impact of reuse and reusability in different life cycle stages

In the context of circular construction, the (potential) reuse of construction materials and building products is set forward as a general concept to reduce the environmental impact of buildings. But does this really lead to reduced impacts? A standardised framework to calculate the environmental impact of buildings over their life cycle is available through the European standards EN15804+A2 and EN15978 for life cycle analysis (LCA) in construction. The concept of reuse does however intrinsically focus on multiple use or life cycles. A correct quantification of the environmental impacts of reuse in buildings, requires a better understanding of the different mechanisms and issues at play. By means of critical assessment of the LCA methodology, in combination with a simplified case study, this paper provides insights in how different reuse options for products are valorised (or not) when calculating the environmental impact. It is shown that the LCA standard EN15804+A2 allows to quantify the impact related to different concepts of reuse at the beginning or the end of the considered life cycle. In general reused products will lead to larger environmental gains as the production stage (A1-A3) can be avoided. The environmental benefit related to the reusability of a product is typically reflected in a smaller difference in the end-of-life (EOL) stage (C1-C4). Also the relevance of existing concepts, such as module D, is discussed for each of the considered reuse options. Results show that module D can provide insights in the future potential of reuse (at EOL) for virgin products, but that the numbers are difficult to interpret and even misleading for reuse products. The results and discussion show the limitations of the current LCA framework for these types of products and identify the need for the integration of additional concepts to correctly valorise the potential of reusable products using LCA.

Prospective environmental assessment of reprocessing and valorization alternatives for sulfidic copper tailings

Waste from primary mining operations, especially mine tailings, receive much attention as potential secondary resources that can transform liabilities into resources. The primary intention is to minimize mine tailings disposal problems through volume reduction while recovering secondary resources for industrial materials. However, the environmental benefits and tradeoffs behind these objectives remain unclear. This study conducts a process-based life cycle assessment (LCA) study to investigate multiple reprocessing pathways of copper tailings to co-produce secondary metals and building materials. Four design options representing different value-recovery routes are constructed to assess the environmental burdens of reprocessing chains and the associated benefits from displaced virgin products. This study assesses emerging technologies in a prospective LCA, with projections of bottom-up foreground process modeling and background data like energy supply scenarios. Our analysis reveals that the assessed technologies can only be beneficial when all co-products are utilized. Results indicate that reprocessing may save from 25 up to 930 kg CO2-eq per tonne of treated copper tailings. Potential environmental benefits depend on the reprocessing routes, technology upscaling parameters, and quality of secondary products. We propose recommendations to enhance the environmental performances of mine tailings reprocessing strategies, such as switching to low-impact chemical alternatives and optimizing energy use. Our findings can support the sustainable development of the metal industry in terms of waste management and secondary resource use.

Safety assessment of antimicrobials in food packaging paper based on LC-MS method

Many difficulties relating to food safety have been solved thanks to the employment of strong mass spectrometric detectors in conjunction with liquid chromatography. In this study, samples were fractionated using gel permeation chromatography and liquid/liquid extraction, and liquid chromatography/mass spectrometry (LC/MS) and gas chromatography/mass spectrometry were used to detect possible genotoxicant(s) in recycled paperboard. As a genotoxicity indicator, the rec-assay was utilized. Abietic acid (AA) and dehydroabietic acid (DHA) and were discovered in the recycled paperboard to be genotoxic. AA and DHA were found in 2 of 5 virgin products and all seven recycled food-contact products. AA and DHA total levels in virgin goods were 990 and 240 mg/g, respectively, whereas recycled products had 200990 mg/g. The total quantity of AA and DHA content in DNA-damaging activity and paper products were shown to have a strong connection. Furthermore, genotoxic effects in paper products matched standard chemicals well, showing that AA and DHA were primarily responsible for the genotoxic effects of these paper products.

Chemical Characterization of Recycled Consumer Products Using Suspect Screening Analysis.

Recycled materials are found in many consumer products as part of a circular economy; however, the chemical content of recycled products is generally uncharacterized. A suspect screening analysis using two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS) was applied to 210 products (154 recycled, 56 virgin) across seven categories. Chemicals in products were tentatively identified using a standard spectral library or confirmed using chemical standards. A total of 918 probable chemical structures identified (112 of which were confirmed) in recycled materials versus 587 (110 confirmed) in virgin materials. Identified chemicals were characterized in terms of their functional use and structural class. Recycled paper products and construction materials contained greater numbers of chemicals than virgin products; 733 identified chemicals had greater occurrence in recycled compared to virgin materials. Products made from recycled materials contained greater numbers of fragrances, flame retardants, solvents, biocides, and dyes. The results were clustered to identify groups of chemicals potentially associated with unique chemical sources, and identified chemicals were prioritized for further study using high-throughput hazard and exposure information. While occurrence is not necessarily indicative of risk, these results can be used to inform the expansion of existing models or identify exposure pathways currently neglected in exposure assessments.

Environmental impact assessment of zero waste approach for carbon fiber prepreg scraps

In the present paper, the environmental impact of an innovative technology, based on a zero-waste approach, for reclaiming carbon fiber prepreg scraps is assessed. The innovative process, proposed within the European project CIRCE, aims at reclaiming scraps produced during the cutting operation of virgin prepreg, avoiding the waste materials landfilling or incineration. The prepreg scraps were transformed into a ready-to-use raw secondary material by using two specifically developed automated systems for cutting and peeling of the scraps. By exploiting the prepared scraps in a compression molding process, recycled composite parts were produced. The evaluation of the environmental impact was carried out by means of the Life Cycle Assessment (LCA) approach, using the different impact assessment methodologies based on the Cumulative Energy Demand, Global Warming Potential and ReCiPe methods. Furthermore, tensile tests were performed at room temperature to investigate the mechanical properties of the recovered scraps products. In order to evaluate the environmental benefits of the innovative compression molding production with recovered prepreg scraps, the LCA analysis was also performed on two different traditional virgin production scenarios, i.e. the compression molding production with virgin prepreg and the autoclave processing with virgin prepregs, both used for the production of CFRP parts. The results show that the reclaim process leads to a strong reduction of the environmental impacts with respect to traditional composite production processes, demonstrating that such process can represent a valid alternative for a more sustainable manufacturing of composite products.

Stochastic consequential Life Cycle Assessment of technology substitution in the case of a novel PET chemical recycling technology

The current traditional mechanical recycling of Polyethylene Terephthalate (PET) grinds the waste into granulate, yet the resulting secondary material quality is strongly dependent on the efficiency of the selection processes, leading to the requirement of an integration of fossil PET to assure the bottle-grade quality is reached. Instead, the novel chemical recycling gr3n technology depolymerizes the waste PET back into the constituent monomers with a resulting quality that is comparable to the virgin product, due to a more efficient separation of impurities. In order to estimate the environmental impacts related to the introduction of this technology in the related market, Consequential Life Cycle Assessment (CLCA) is particularly indicated. Among the consequential approaches, we adopt the Stochastic Technology Choice Model, as it is able to model the technological mixes typical of markets based on costs and production capacities, while its stochasticity suits the need to manage the uncertainty of future market conditions. Indeed, the assessment of the expected technological mixes contributing to the same function and the quality of the recycled material are key to evaluate the variation in marginal LCA impacts due to the introduction of the gr3n technology. We assess the marginal LCA impacts of the European bottle-grade PET market in two scenarios: one in which the gr3n technology is not available and one in which this technology is present. To correctly evaluate the difference between these two scenarios, we perform a paired simulation. Here we show that the populations related to this difference show more than 50% negative results in 12 out of 16 impact indicators and more than 75% of negative results in 9 out of 16 impact indicators. In particular, a median 0.13 kg CO2-eq per kg bottle-grade PET could be saved by the introduction of gr3n, equivalent to a 5% reduction. We show that the 5–95 percentiles range of the difference between the two scenarios is only 17.7% of the average range defined by the two separate scenarios distributions, confirming previous findings from the literature. The robustness of the results is tested through three sensitivity analyses. Therefore, policy makers should focus on limiting the increase in marginal demand of PET and on creating fair conditions for this chemical recycling technology to be deployed to complement mechanical recycling in reducing virgin PET production, thus decreasing potential environmental impacts and fostering a more circular economy. The positive performance of the novel technology is strongly related to the increased substitution of waste treatment processes, such as incineration and landfill, and to the increased quality of the recycled product: this environmental profile could further improve as the novel technology will scale up industrially.

Combining Life Cycle Assessment and Circularity Assessment to Analyze Environmental Impacts of the Medical Remanufacturing of Electrophysiology Catheters

Sustaining value after the end-of-life to improve products’ circularity and sustainability has attracted an increasing number of industrial actors, policymakers, and researchers. Medical products are considered to have great remanufacturing potential because they are often designated as single-use products and consist of various complex materials that cannot be reused and are not significant in municipal recycling infrastructure. The remanufacturing of electrophysiology catheters is a well-established process guaranteeing equivalent quality compared to virgin-produced catheters. In order to measure if using a remanufactured product is environmentally beneficial compared to using a virgin product, life cycle assessment (LCA) is often used. However, focusing on one life cycle to inform on the environmental-beneficial use fails to guide policymakers from a system perspective. This study analyzes the environmental consequences of electrophysiology catheters considering two modeling perspectives, the implementation of LCA, including a cut-off approach and combining LCA and a circularity indicator measuring multiple life cycles. Investigating the LCA results of using a remanufactured as an alternative to a newly-manufactured catheter shows that the global warming impact is reduced by 50.4% and the abiotic resource use by 28.8%. The findings from the system perspective suggest that the environmental savings increase with increasing collection rates of catheters.

Environmental impact of discarded apparel landfilling and recycling

ABSTRACT Globally, around 87% of discarded textiles ended up in landfill, of which more than 90% are reusable and recyclable. Recycling textile waste to other value-added products is economically feasible. To integrate recycling into the apparel waste stream, it is important to know the environmental benefit and impact of the different recycling options. This study presents the environmental performance of apparel recycling and landfill using the life cycle assessment methodology in terms of climate change, acidification, agricultural land occupation and water depletion. Landfill scenarios and recycling scenarios of post-consumer household discarded apparel waste have been developed in the context of Australia. This study finds that the landfill process of natural apparel waste contributes more environmental impact credit compared to synthetic apparel, and this is mainly credited from the power generation from landfill methane gas captured. This study also specifies that the environmental benefit from the landfill process of discarded apparel depends on the ratio of natural fibre and synthetic fibre in discarded apparel. Integration of recycling into the apparel waste stream can potentially generate environmental benefits. A recycling scenario of cleaning wipes shows the highest impact benefits, followed by cotton fibre, insulation material and polyester raw material recycling. Net impact savings of recycling depend on the avoided landfill impact and avoided virgin production impact. The results generated from this study can be useful for future policy recommendations on apparel waste management through recycling. It is clear that increased collection of apparel by recyclers can significantly reduce environmental impact.

Environmental life cycle assessment of the recycling processes of waste plastics recovered by landfill mining

Enhanced Landfill Mining (ELFM) is a powerful tool for the sustainable management of landfill sites, aiming at both land reclamation and material recovery/reuse. To enhance the recovery and recycling rate of excavated plastic fractions, in most cases destined to energy recovery, new convenient, effective and sustainable strategies are needed. In this study, a recovery and valorization process of ELFM excavated plastics has been validated through an integrated experimental and Life Cycle Assessment (LCA) approach, demonstrating the environmental sustainability of the secondary raw material generated, in terms of use of resources and emissions generated. In particular, the secondary granulate from ELFM was compared with a virgin product and the last one resulted to have a higher impact (more than 4.46 times greater than the first one), in particular for the use of the resource crude oil as raw material in the production of primary LDPE. The valorization process of the excavated plastic made the mechanical properties of the secondary raw material comparable to that of a primary material.