Pub Date : 2023-11-19DOI: 10.3390/recycling8060093
Domenico Asprone, Dariusz Mierzwi´nski, Kritish Thoudam, N. Hossiney, Srinidhi Lakshmish Kumar, Jacob Alex, Sanoop Prakasan, Sarath Chandra, Yogeshraj Urs, A. S. Arunkumar
With the advent of the COVID-19 pandemic, the global consumption of single-use surgical masks has risen immensely, and it is expected to grow in the coming years. Simultaneously, the disposal of surgical masks in the environment has caused plastic pollution, and therefore, it is exigent to find innovative ways to handle this problem. In this study, surgical masks were processed in a laboratory using the mechanical grinding method to obtain recycled surgical masks (RSM). The RSM was added in doses of 0%, 1%, 2%, 3%, and 4% by volume of geopolymer bricks, which were synthesized with ground granulated blast furnace slag (GGBS), rice husk ash (RHA), sand, and sodium silicate (Na2SiO3) at ambient conditions for a duration of 28 days. The developed bricks were tested for compressive strength, flexural strength, density, water absorption, efflorescence, and drying shrinkage. The results of the study reveal that compressive strength and flexural strength improved with the inclusion of RSM in the bricks. The highest values of compressive strength and flexural strength were 5.97 MPa and 1.62 MPa for bricks with 4% RSM, respectively. Further, a reduction in the self-weight of the bricks was noticed with an increase in RSM. There was no pronounced effect of RSM on the water absorption and efflorescence properties. However, the RSM played a role in reducing the drying shrinkage of the bricks. The sustainability analysis divulges the catalytic role of RSM in improving material performance, thereby proving to be a potential candidate for low-carbon material in the construction industry.
{"title":"Recycled Surgical Mask Waste as a Resource Material in Sustainable Geopolymer Bricks","authors":"Domenico Asprone, Dariusz Mierzwi´nski, Kritish Thoudam, N. Hossiney, Srinidhi Lakshmish Kumar, Jacob Alex, Sanoop Prakasan, Sarath Chandra, Yogeshraj Urs, A. S. Arunkumar","doi":"10.3390/recycling8060093","DOIUrl":"https://doi.org/10.3390/recycling8060093","url":null,"abstract":"With the advent of the COVID-19 pandemic, the global consumption of single-use surgical masks has risen immensely, and it is expected to grow in the coming years. Simultaneously, the disposal of surgical masks in the environment has caused plastic pollution, and therefore, it is exigent to find innovative ways to handle this problem. In this study, surgical masks were processed in a laboratory using the mechanical grinding method to obtain recycled surgical masks (RSM). The RSM was added in doses of 0%, 1%, 2%, 3%, and 4% by volume of geopolymer bricks, which were synthesized with ground granulated blast furnace slag (GGBS), rice husk ash (RHA), sand, and sodium silicate (Na2SiO3) at ambient conditions for a duration of 28 days. The developed bricks were tested for compressive strength, flexural strength, density, water absorption, efflorescence, and drying shrinkage. The results of the study reveal that compressive strength and flexural strength improved with the inclusion of RSM in the bricks. The highest values of compressive strength and flexural strength were 5.97 MPa and 1.62 MPa for bricks with 4% RSM, respectively. Further, a reduction in the self-weight of the bricks was noticed with an increase in RSM. There was no pronounced effect of RSM on the water absorption and efflorescence properties. However, the RSM played a role in reducing the drying shrinkage of the bricks. The sustainability analysis divulges the catalytic role of RSM in improving material performance, thereby proving to be a potential candidate for low-carbon material in the construction industry.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2023-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139259800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-18DOI: 10.3390/recycling8060092
Yingtong Chen, Wei-Ping Chiang, Ping-Yu Hsieh
Steelmaking processes inevitably generate large amounts of byproducts, including slags, specks of dust, etc., and their treatment has been a critical issue for the steelmaking industry. Kish graphite is a valuable substance existing in steelmaking byproducts, and the recovery of Kish graphite has attracted more attention in recent years. The purpose of this study was to use a multi-stage froth flotation process for the beneficiation of Kish graphite and to investigate the influence of flotation conditions on the mass distribution of graphite and impurities. The results showed that the dust D2 contained ~34 wt.% of graphite and thus had the highest potential for the recovery of Kish graphite. The dosages of frother (methyl isobutyl carbinol, MIBC) at 0.005 kg/t and collector (kerosene) at 1 kg/t were optimal for the flotation of Kish graphite. After three-stage froth flotation, the graphite content of the concentrate was progressively increased to 84.09 wt.%, and the entire recovery rate was 93.05%. During the multi-stage froth flotation process, most of the impurities were separated in stage I, but the Fe-containing impurities were mainly separated in stage II. Some Ca2+, Na+, and K+ were leached out, and there were barely any heavy metals in the liquid phases.
{"title":"Recovery of Kish Graphite from Steelmaking Byproducts with a Multi-Stage Froth Flotation Process","authors":"Yingtong Chen, Wei-Ping Chiang, Ping-Yu Hsieh","doi":"10.3390/recycling8060092","DOIUrl":"https://doi.org/10.3390/recycling8060092","url":null,"abstract":"Steelmaking processes inevitably generate large amounts of byproducts, including slags, specks of dust, etc., and their treatment has been a critical issue for the steelmaking industry. Kish graphite is a valuable substance existing in steelmaking byproducts, and the recovery of Kish graphite has attracted more attention in recent years. The purpose of this study was to use a multi-stage froth flotation process for the beneficiation of Kish graphite and to investigate the influence of flotation conditions on the mass distribution of graphite and impurities. The results showed that the dust D2 contained ~34 wt.% of graphite and thus had the highest potential for the recovery of Kish graphite. The dosages of frother (methyl isobutyl carbinol, MIBC) at 0.005 kg/t and collector (kerosene) at 1 kg/t were optimal for the flotation of Kish graphite. After three-stage froth flotation, the graphite content of the concentrate was progressively increased to 84.09 wt.%, and the entire recovery rate was 93.05%. During the multi-stage froth flotation process, most of the impurities were separated in stage I, but the Fe-containing impurities were mainly separated in stage II. Some Ca2+, Na+, and K+ were leached out, and there were barely any heavy metals in the liquid phases.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2023-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139262148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-11DOI: 10.3390/recycling8060091
Abu Elnasr E. Sobaih, Ahmed E. Abu Elnasr
Background: The proportion of food waste in the Kingdom of Saudi Arabia, particularly in food service outlets, sends an important and urgent call for a holistic model to either prevent or at least properly manage this high level of food waste. This study draws on the European Union Waste Hierarchy Framework and the United States Environmental Protection Agency Food Recovery Framework to develop a holistic model to manage the high rate of food waste in Saudi food service outlets. Methods: This study adopted the Standards for Reporting Qualitative Research using one-to-one interviews with food service experts to explore the current and appropriate practices for food waste prevention. The in-depth interviews discussed the implementation of the 5Rs hierarchy, which includes reducing food surplus and waste at the source, redistributing food surplus to needy people, reusing food surplus/waste, recycling food waste, and recovering food waste benefits, i.e., bioenergy production. Results: The successful implementation of the 5Rs hierarchy depends on effective collaboration between the key stakeholders, i.e., policy makers, food industry administrators, non-governmental organizations, and customers. The effective management of the food supply chain is also vital to avoid food surplus and prevent waste in food service outlets. Additionally, sustainable production by staff and responsible consumption by consumers contribute effectively to the implementation of the 5Rs model, which contributes to the achievement of zero food waste and, ultimately, to sustainable development. Conclusions: This study provided a novel hierarchy model, which has five tiers, aiming to avoid food waste. The successful implementation of this model will lead to several significant positive impacts on the economy, community, and environment.
{"title":"Exploring the 5Rs Holistic Model for Zero Food Waste in Saudi Arabian Food Service Outlets","authors":"Abu Elnasr E. Sobaih, Ahmed E. Abu Elnasr","doi":"10.3390/recycling8060091","DOIUrl":"https://doi.org/10.3390/recycling8060091","url":null,"abstract":"Background: The proportion of food waste in the Kingdom of Saudi Arabia, particularly in food service outlets, sends an important and urgent call for a holistic model to either prevent or at least properly manage this high level of food waste. This study draws on the European Union Waste Hierarchy Framework and the United States Environmental Protection Agency Food Recovery Framework to develop a holistic model to manage the high rate of food waste in Saudi food service outlets. Methods: This study adopted the Standards for Reporting Qualitative Research using one-to-one interviews with food service experts to explore the current and appropriate practices for food waste prevention. The in-depth interviews discussed the implementation of the 5Rs hierarchy, which includes reducing food surplus and waste at the source, redistributing food surplus to needy people, reusing food surplus/waste, recycling food waste, and recovering food waste benefits, i.e., bioenergy production. Results: The successful implementation of the 5Rs hierarchy depends on effective collaboration between the key stakeholders, i.e., policy makers, food industry administrators, non-governmental organizations, and customers. The effective management of the food supply chain is also vital to avoid food surplus and prevent waste in food service outlets. Additionally, sustainable production by staff and responsible consumption by consumers contribute effectively to the implementation of the 5Rs model, which contributes to the achievement of zero food waste and, ultimately, to sustainable development. Conclusions: This study provided a novel hierarchy model, which has five tiers, aiming to avoid food waste. The successful implementation of this model will lead to several significant positive impacts on the economy, community, and environment.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135086635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-11DOI: 10.3390/recycling8060090
Chaojie Yu, Diyi Jin, Xichao Hu, Wenzhi He, Guangming Li
Given their exceptional performance, plastic packaging products are widely used in daily life, and the dramatic expansion in plastic packaging waste (PPW) has exacerbated environmental problems. Many countries have enacted laws and developed recycling technologies to manage plastic packaging waste in consideration of the nature of PPW as both garbage and a resource. As the world’s largest producer and consumer of plastics, China has also taken measures to address this issue. This paper presents the latest management regulations and recycling strategies for PPW in China. Based on an analysis of the current management status of PPW and recycling technologies and their carbon emission impacts, some management suggestions and a comprehensive full-chain recycling process were put forward. We supposed that management challenges that need to be overcome in the future can be solved through the improvement of green designs for plastic packaging, manufacturing technology updates, consumption concept changes, and the high-value utilization of PPW. This paper aims to provide valuable references for government decisions on PPW management and, furthermore, to set up an economically sensible and industrially feasible PPW solution and boost the development of PPW recycling.
{"title":"An Overview of Management Status and Recycling Strategies for Plastic Packaging Waste in China","authors":"Chaojie Yu, Diyi Jin, Xichao Hu, Wenzhi He, Guangming Li","doi":"10.3390/recycling8060090","DOIUrl":"https://doi.org/10.3390/recycling8060090","url":null,"abstract":"Given their exceptional performance, plastic packaging products are widely used in daily life, and the dramatic expansion in plastic packaging waste (PPW) has exacerbated environmental problems. Many countries have enacted laws and developed recycling technologies to manage plastic packaging waste in consideration of the nature of PPW as both garbage and a resource. As the world’s largest producer and consumer of plastics, China has also taken measures to address this issue. This paper presents the latest management regulations and recycling strategies for PPW in China. Based on an analysis of the current management status of PPW and recycling technologies and their carbon emission impacts, some management suggestions and a comprehensive full-chain recycling process were put forward. We supposed that management challenges that need to be overcome in the future can be solved through the improvement of green designs for plastic packaging, manufacturing technology updates, consumption concept changes, and the high-value utilization of PPW. This paper aims to provide valuable references for government decisions on PPW management and, furthermore, to set up an economically sensible and industrially feasible PPW solution and boost the development of PPW recycling.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135086598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-08DOI: 10.3390/recycling8060089
Domenic Klohs, Christian Offermanns, Heiner Heimes, Achim Kampker
As the market share of electric vehicles continues to rise, the number of battery systems that are retired after their service life in the vehicle will also increase. This large growth in battery returns will also have a noticeable impact on processes such as battery disassembly. The purpose of this paper is, therefore, to examine the challenges of the battery disassembly process in relation to the required increase in the degree of automation. For this purpose, a survey of various experts along the battery value chain was conducted, and product-side hurdles, such as the wide range of variants, and process-side challenges, such as the opening of the housing cover or the removal of cables and connectors, were identified. Together with an assessment of the potential degree of automation in the context of downstream processes (reuse, repair, remanufacturing, and recycling), this results in a variety of streams for future research in the field of automated battery disassembly. The core aspect in this context is data availability consisting of product and component data as well as process-relevant parameters.
{"title":"Automated Battery Disassembly—Examination of the Product- and Process-Related Challenges for Automotive Traction Batteries","authors":"Domenic Klohs, Christian Offermanns, Heiner Heimes, Achim Kampker","doi":"10.3390/recycling8060089","DOIUrl":"https://doi.org/10.3390/recycling8060089","url":null,"abstract":"As the market share of electric vehicles continues to rise, the number of battery systems that are retired after their service life in the vehicle will also increase. This large growth in battery returns will also have a noticeable impact on processes such as battery disassembly. The purpose of this paper is, therefore, to examine the challenges of the battery disassembly process in relation to the required increase in the degree of automation. For this purpose, a survey of various experts along the battery value chain was conducted, and product-side hurdles, such as the wide range of variants, and process-side challenges, such as the opening of the housing cover or the removal of cables and connectors, were identified. Together with an assessment of the potential degree of automation in the context of downstream processes (reuse, repair, remanufacturing, and recycling), this results in a variety of streams for future research in the field of automated battery disassembly. The core aspect in this context is data availability consisting of product and component data as well as process-relevant parameters.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135393275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-07DOI: 10.3390/recycling8060088
Idowu D. Ibrahim, Emmanuel R. Sadiku, Yskandar Hamam, Williams K. Kupolati, Julius M. Ndambuki, Tamba Jamiru, Azunna A. Eze, Jacques Snyman
Packaging materials play a significant role in the meat, fish, and seafood, pharmaceutical, beverages, and electronics industries. These materials protect the contents during handling and transportation from damage, contamination, and loss of quality, thus enhancing the shelf life of the products being packaged. Several materials, like paper and cardboard, plastics, metals, and glass, have been widely used. However, the vast consumption of these materials leads to high waste generation due to increasing demands globally. This article considers some aspects of recycling waste packaging materials, the need for recycling in terms of environmental impacts, and the energy-saving and economic benefits. It also provides some highlights on the sustainability of the processes of recycling and how the government and public can influence recycling operations. The impact of the COVID-19 pandemic on packaging systems and solid waste management is also highlighted. This study also provides a short note on the possible future methods to be adopted in the recycling process of waste packaging materials.
{"title":"Recent Recycling Innovations to Facilitate Sustainable Packaging Materials: A Review","authors":"Idowu D. Ibrahim, Emmanuel R. Sadiku, Yskandar Hamam, Williams K. Kupolati, Julius M. Ndambuki, Tamba Jamiru, Azunna A. Eze, Jacques Snyman","doi":"10.3390/recycling8060088","DOIUrl":"https://doi.org/10.3390/recycling8060088","url":null,"abstract":"Packaging materials play a significant role in the meat, fish, and seafood, pharmaceutical, beverages, and electronics industries. These materials protect the contents during handling and transportation from damage, contamination, and loss of quality, thus enhancing the shelf life of the products being packaged. Several materials, like paper and cardboard, plastics, metals, and glass, have been widely used. However, the vast consumption of these materials leads to high waste generation due to increasing demands globally. This article considers some aspects of recycling waste packaging materials, the need for recycling in terms of environmental impacts, and the energy-saving and economic benefits. It also provides some highlights on the sustainability of the processes of recycling and how the government and public can influence recycling operations. The impact of the COVID-19 pandemic on packaging systems and solid waste management is also highlighted. This study also provides a short note on the possible future methods to be adopted in the recycling process of waste packaging materials.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135433117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-04DOI: 10.3390/recycling8060087
Elisa Mayrhofer, Lukas Prielinger, Victor Sharp, Bernhard Rainer, Christian Kirchnawy, Christian Rung, Anita Gruner, Mladen Juric, Arielle Springer
European circular economy goals require the use of recycled polymers in sensitive applications such as food packaging. As plastic recyclates can contain unknown post-consumer substances, the European Food Safety Authority evaluates recycling processes using a worst-case assumption: all contaminants are DNA-reactive mutagens/carcinogens with extremely low safety thresholds. The current data are insufficient to estimate whether this assumption is justified. To provide scientific evidence on the presence of DNA-reactive mutagens in recycled plastics, 119 input and output samples from plastic recycling were tested with a miniaturized Ames test. DNA-reactive mutagens were not detected in recycled polyethylene terephthalate, which is already approved for food contact. However, other types of recycled plastics (polyethylene, polypropylene and polystyrene), which are currently unauthorized for food contact, showed DNA-reactive, mutagenic effects in a total of 51 samples. The DNA-reactive substances that are responsible for the detected mutagenic activity could not be identified by comparison of the bioassay data with analytical results from a chromatographical screening. The data from the Ames test analysis of different independent batches and a comparison of input and output material indicate that the DNA-reactive contaminants are not randomly introduced through the misuse of recycled packaging by consumers, but are systematically formed during the recycling process from precursors in the input. This publication highlights the need to identify the source for this critical contaminant to enable the future use of polyethylene, polypropylene and polystyrene in sensitive applications.
{"title":"Safety Assessment of Recycled Plastics from Post-Consumer Waste with a Combination of a Miniaturized Ames Test and Chromatographic Analysis","authors":"Elisa Mayrhofer, Lukas Prielinger, Victor Sharp, Bernhard Rainer, Christian Kirchnawy, Christian Rung, Anita Gruner, Mladen Juric, Arielle Springer","doi":"10.3390/recycling8060087","DOIUrl":"https://doi.org/10.3390/recycling8060087","url":null,"abstract":"European circular economy goals require the use of recycled polymers in sensitive applications such as food packaging. As plastic recyclates can contain unknown post-consumer substances, the European Food Safety Authority evaluates recycling processes using a worst-case assumption: all contaminants are DNA-reactive mutagens/carcinogens with extremely low safety thresholds. The current data are insufficient to estimate whether this assumption is justified. To provide scientific evidence on the presence of DNA-reactive mutagens in recycled plastics, 119 input and output samples from plastic recycling were tested with a miniaturized Ames test. DNA-reactive mutagens were not detected in recycled polyethylene terephthalate, which is already approved for food contact. However, other types of recycled plastics (polyethylene, polypropylene and polystyrene), which are currently unauthorized for food contact, showed DNA-reactive, mutagenic effects in a total of 51 samples. The DNA-reactive substances that are responsible for the detected mutagenic activity could not be identified by comparison of the bioassay data with analytical results from a chromatographical screening. The data from the Ames test analysis of different independent batches and a comparison of input and output material indicate that the DNA-reactive contaminants are not randomly introduced through the misuse of recycled packaging by consumers, but are systematically formed during the recycling process from precursors in the input. This publication highlights the need to identify the source for this critical contaminant to enable the future use of polyethylene, polypropylene and polystyrene in sensitive applications.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135775622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-02DOI: 10.3390/recycling8060086
Juan Carlos Arbeláez-Estrada, Paola Vallejo, Jose Aguilar, Marta Silvia Tabares-Betancur, David Ríos-Zapata, Santiago Ruiz-Arenas, Elizabeth Rendón-Vélez
Proper waste separation is essential for recycling. However, it can be challenging to identify waste materials accurately, especially in real-world settings. In this study, a systematic literature review (SLR) was carried out to identify the physical enablers (sensors and computing devices), datasets, and machine learning (ML) algorithms used for waste identification in indirect separation systems. This review analyzed 55 studies, following the Kitchenham guidelines. The SLR identified three levels of autonomy in waste segregation systems: full, moderate, and low. Edge computing devices are the most widely used for data processing (9 of 17 studies). Five types of sensors are used for waste identification: inductive, capacitive, image-based, sound-based, and weight-based sensors. Visible-image-based sensors are the most common in the literature. Single classification is the most popular dataset type (65%), followed by bounding box detection (22.5%). Convolutional neural networks (CNNs) are the most commonly used ML technique for waste identification (24 out of 26 articles). One of the main conclusions is that waste identification faces challenges with real-world complexity, limited data in datasets, and a lack of detailed waste categorization. Future work in waste identification should focus on deployment and testing in non-controlled environments, expanding system functionalities, and exploring sensor fusion.
{"title":"A Systematic Literature Review of Waste Identification in Automatic Separation Systems","authors":"Juan Carlos Arbeláez-Estrada, Paola Vallejo, Jose Aguilar, Marta Silvia Tabares-Betancur, David Ríos-Zapata, Santiago Ruiz-Arenas, Elizabeth Rendón-Vélez","doi":"10.3390/recycling8060086","DOIUrl":"https://doi.org/10.3390/recycling8060086","url":null,"abstract":"Proper waste separation is essential for recycling. However, it can be challenging to identify waste materials accurately, especially in real-world settings. In this study, a systematic literature review (SLR) was carried out to identify the physical enablers (sensors and computing devices), datasets, and machine learning (ML) algorithms used for waste identification in indirect separation systems. This review analyzed 55 studies, following the Kitchenham guidelines. The SLR identified three levels of autonomy in waste segregation systems: full, moderate, and low. Edge computing devices are the most widely used for data processing (9 of 17 studies). Five types of sensors are used for waste identification: inductive, capacitive, image-based, sound-based, and weight-based sensors. Visible-image-based sensors are the most common in the literature. Single classification is the most popular dataset type (65%), followed by bounding box detection (22.5%). Convolutional neural networks (CNNs) are the most commonly used ML technique for waste identification (24 out of 26 articles). One of the main conclusions is that waste identification faces challenges with real-world complexity, limited data in datasets, and a lack of detailed waste categorization. Future work in waste identification should focus on deployment and testing in non-controlled environments, expanding system functionalities, and exploring sensor fusion.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135934858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Determination of the chemical composition of waste Sm-Co magnets is required for their efficient recycling. The non-stereotypical composition of said magnets makes an analysis extremely challenging. X-ray fluorescence spectrometry is a promising analytical tool for this task. It offers high accuracy and simplicity of sample preparation as it does not require sample dissolution. However, a serious limitation of X-ray fluorescence analysis is the spectral interference of matrix elements and impurities. In this work, a two-stage technique has been developed for the determination of the main components (Sm, Co) and impurities (Fe, Cu, Zr, Hf, Ti, Ni, Mn, Cr) in samples of spent samarium–cobalt magnets using wavelength dispersive X-ray fluorescence spectrometry. In order to overcome the main limitation of the chosen method and to maximize its capabilities of qualitative and quantitative analysis, we propose an approach to the selection of analytical lines and experimental conditions, as well as a preparation method for the calibration standards. The obtained results have been shown to have a good correlation with ICP-OES. The limits of detection are in the range of 0.001–0.02 wt%, and the limits of quantification are 0.003–0.08 wt%.
{"title":"X-ray Fluorescence Analysis of Waste Sm-Co Magnets: A Rational Approach","authors":"Alexandra Alexandrovna Arkhipenko, Galina Evgenievna Marina, Marina Sergeevna Doronina, Natalya Alexandrovna Korotkova, Vasilisa Borisovna Baranovskaya","doi":"10.3390/recycling8060084","DOIUrl":"https://doi.org/10.3390/recycling8060084","url":null,"abstract":"Determination of the chemical composition of waste Sm-Co magnets is required for their efficient recycling. The non-stereotypical composition of said magnets makes an analysis extremely challenging. X-ray fluorescence spectrometry is a promising analytical tool for this task. It offers high accuracy and simplicity of sample preparation as it does not require sample dissolution. However, a serious limitation of X-ray fluorescence analysis is the spectral interference of matrix elements and impurities. In this work, a two-stage technique has been developed for the determination of the main components (Sm, Co) and impurities (Fe, Cu, Zr, Hf, Ti, Ni, Mn, Cr) in samples of spent samarium–cobalt magnets using wavelength dispersive X-ray fluorescence spectrometry. In order to overcome the main limitation of the chosen method and to maximize its capabilities of qualitative and quantitative analysis, we propose an approach to the selection of analytical lines and experimental conditions, as well as a preparation method for the calibration standards. The obtained results have been shown to have a good correlation with ICP-OES. The limits of detection are in the range of 0.001–0.02 wt%, and the limits of quantification are 0.003–0.08 wt%.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135220821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.3390/recycling8060085
Weslei M. Ambrós
Urban mining has emerged as a concept that goes beyond conventional recycling, as it aims to tackle both the challenges of solid waste generation and management, as well as the scarcity of primary resources. Gravity concentration has gained increasing attention as a promising method for addressing crucial challenges in urban mining applications. In this sense, this review provides a comprehensive and up-to-date overview of gravity concentration in urban mining processes, covering principles, techniques, current applications, recent advancements, challenges, and opportunities. Emphasis was placed on shifting from the commonly found literature focus on ore processing to solid waste processing. Three types of solid waste, namely plastics, construction and demolition waste (CDW), and waste from electrical and electronic equipment (WEEE), were chosen for a more in-depth examination due to their massive production and widespread generation. Discussions also considered the potential of gravity concentration to address the unique challenges in their processing and explored possibilities for future developments.
{"title":"Gravity Concentration in Urban Mining Applications—A Review","authors":"Weslei M. Ambrós","doi":"10.3390/recycling8060085","DOIUrl":"https://doi.org/10.3390/recycling8060085","url":null,"abstract":"Urban mining has emerged as a concept that goes beyond conventional recycling, as it aims to tackle both the challenges of solid waste generation and management, as well as the scarcity of primary resources. Gravity concentration has gained increasing attention as a promising method for addressing crucial challenges in urban mining applications. In this sense, this review provides a comprehensive and up-to-date overview of gravity concentration in urban mining processes, covering principles, techniques, current applications, recent advancements, challenges, and opportunities. Emphasis was placed on shifting from the commonly found literature focus on ore processing to solid waste processing. Three types of solid waste, namely plastics, construction and demolition waste (CDW), and waste from electrical and electronic equipment (WEEE), were chosen for a more in-depth examination due to their massive production and widespread generation. Discussions also considered the potential of gravity concentration to address the unique challenges in their processing and explored possibilities for future developments.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135221730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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