Quality Of Recycled Materials Research Articles

Assessing performance in lithium-ion batteries recycling processes: A quantitative modeling perspective

In the shift toward sustainable energy solutions, the efficiency of lithium-ion battery (LIB) recycling within the supply chain is of paramount importance. This study evaluates the performance of LIB recycling processes by advancing a quantitative modeling approach. Through process simulations, a comprehensive assessment of pyrometallurgical and hydrometallurgical LIB recycling processes is presented by focusing on the key parameters that influence material recoveries and yields. Recycling efficiency indicators, accounting for the quantity and quality of recycled materials, are introduced and their dependence on the share of different battery chemistries and formats in the spent batteries feed is assessed via numerical simulations. A sensitivity analysis of process parameters identifies the unit operations mostly affecting the recycling performance, highlighting process criticalities. The model presented and its outcomes provide a valuable guide for stakeholders in the LIB industry, aiding informed decision-making to enhance sustainability and resource recovery in the ecosystem of electrochemical energy storage.

Towards closed-loop material flow in additive manufacturing: Recyclability analysis of thermoplastic waste

Thermoplastic is one of the most popular materials used in additive manufacturing (AM). As the adoption of AM technologies has been rapidly increasing, the feasibility of recycling AM waste and the quality of recycled materials need to be investigated to facilitate closed-loop material flow and cleaner production. In current literature, studies have been performed to compare material property changes before and after recycling, and a certain level of mechanical degradation has been observed. Some material properties such as molecular weight distribution have not yet been investigated in AM recycling. In addition, the recyclability of waste materials under multiple rounds of recycling has not yet been well studied. These knowledge gaps indicate a research need for AM material recyclability evaluation and improvement. In this research, an assessment framework is proposed and implemented to evaluate the recyclability of acrylonitrile butadiene styrene in extrusion-based AM, providing guidelines for quantifying variations of molecular weight distribution, material density, fabrication quality, and mechanical properties under multiple rounds of recycling. Different process parameters and their impact on material recyclability in each round are also studied. Experimental results indicate that the ultimate tensile strength degradation after each recycling round varies from 27% to over 50%; surface roughness increases 29.54% after three rounds of recycling; molecular weight distribution of recycled materials demonstrates obvious shifts, and the polydispersity is decreased by 13.16% after three rounds of recycling. The results of this research will help AM users better understand and implement waste recycling, which will positively impact the AM community by contributing towards achieving cleaner production and enhancing the material efficiency and environmental sustainability of AM.

Sustainability Evaluation of Pyrolysis of Waste Mattresses: A Comparison with Alternative End-of-Life Treatments

There is a major push by governments and value chain partners to move towards circular options for difficult-to-recycle post-consumer products such as waste mattresses.[1] In the Netherlands alone ~1.5 million mattresses are discarded yearly, of which majority (>60%) is incinerated.[2] A sustainable solution to recycle waste mattresses is required to enable the Dutch industry meet the circular economy goals set by the Dutch government.[3] This paper shares major findings from the screening level life cycle assessment (LCA) of four End-of-Life (EoL) options for post-consumer mattresses: landfill, incineration with energy recovery, pyrolysis and mechanical recycling using powdering. The LCA was an important work package of a technology development project with the objective to quantify potential sustainability benefits of the pyrolysis of waste mattresses.[4] The emphasis of the pyrolysis process is on product recovery as chemical feedstock. The study showed that pyrolysis is a better option than incineration in terms of greenhouse gases ( GHG) and cumulative energy demand (CED) for all the studied cases. Base case analysis showed that pyrolysis of waste mattresses can save approximately 526 kg CO2-eq. and approximately 5.1 GJ (24% savings) CED per ton waste mattresses compared to incineration. Finally, the study concluded that mechanical recycling can either be better or worse than pyrolysis depending on the processes and quality of recycled material.

A qualitative assessment of lithium ion battery recycling processes

With the widespread adoption of e-mobility, there are high numbers of lithium Ion batteries (LIB) entering the waste stream. It is imperative that disposal and recycling strategies are developed and implemented. There is an urgent need for safe, environmentally friendly and economically affordable disposal routes for End of Life (EoL) LIBs. This study has looked at 44 commercial recyclers and assessed their recycling and reclamation processes. A novel qualitative assessment matrix termed “Strategic materials Weighting And Value Evaluation" (SWAVE) is proposed and used to compare the strategic importance and value of various materials in EoL LIBs. The sustainability and quality of recycled material are assessed by comparing the final form or composition after the recycling processes, the industrial processes and the industry type (primary sector, manufacturer or recycler). SWAVE is applied to each company, producing a score out of 20, with a higher number indicating that more materials can be recycled. The separation processes and resources from six of the prominent recycling companies are discussed further. The majority of recyclers use one or more of mechanical treatment, pyrometallurgy, or hydrometallurgy, concentrating upon high value metal extraction rather than closed-loop recycling of the metals or component materials, highlighting an environmental and technological gap. To improve the current circular economy of batteries reuse and repurposing of materials (closed-loop recycling), instead of purely recycling or recovery of metals should be considered for further development. Further studies of environmental trade-offs from recycling or recovering one material in preference to another is required.

Households' behavior and social-environmental aspects of using bag dustbin for waste recovery in Tehran.

The suitable dustbin can cause a significant increase in household participation in separated dry waste at production source and recycling rate. This study was conducted on 100 households in Tehran for two weeks for households' wastes without any intervention. After two weeks, the tough-flexible bag dustbins were delivered to the families. At the next stage, by analysing the separated dry wastes by households, comparing the cost of new bag dustbin with plastic garbage bags, and completing some questionnaires, it was concluded that about 92% of households believed that waste bag dustbin was much more accessible and hygienic. The use of plastic garbage bags was decreased an average by 2, after using new bag dustbins. Moreover, the use of bag dustbins has more cost-effectiveness rather than plastic bags (about 54%). Before and after the intervention, the source separation and recovery rate was 0.19 and 0.18, respectively. The amount of wet waste in the waste bag dustbin was decreased to 62.26% after the intervention. The decrease of wet waste in the separated dry waste enhanced the quality of recycled materials.

EXPERIENCE ON IMPLEMENTATION OF HOT IN-PLACE RECYCLING OF ASPHALT CONCRETE IN UKRAINE

Rehabilitation of asphalt concrete layers of road pavements using HIR technologies enables effective elimination of surface defects (rutting, cracking, raveling, bleeding (flushing)) including defects caused by the non-conformity of asphalt concrete to the standard specifications. Due to the economical and ecological advantages, HIR technologies belong to the present-day effective alternative methods of rehabilitation of asphalt concrete pavements. In Ukraine, HIR technologies were first applied on intermediate repair works on an area of the international road I-01 “Kyiv-Chernihiv-Novyye Yarylovichi” in the 2013. Now, HIR technologies have been applied on repair works on numerical objects including areas on such state motor roads as I-01, I-06, N-09, R-10, R-67. The presented paper analyzes the results of monitoring of materials and technologies which was aimed on HIR performance investigation supported by State Road Agency of Ukraine (Ukravtodor) throughout 2014-2018. The results of monitoring of HIR technologies including laboratory evaluation of materials and also field testing of the rehabilitated pavements led to the conclusions fitted by the world-wide experience on implementation of HIR technologies. 1. Being applied to the structurally sound pavements, HIR provides effective elimination of surface defects of flexible pavement to a depth of (50-60) mm including defects caused by the non-conformity of asphalt concrete to the standard specifications. However, HIR is not suitable for existing asphalt pavements which have too much variation in asphalt concrete composition and thickness within the project limits. 2. The efficiency of asphalt pavement rehabilitation using HIR technologies largely depends on precise engineering consideration which determines the efficiency of preparatory (repair) works including some special works such as: – correction of cracks in case of cracking that extends below the depth of hot recycling; – re-compaction of an unbound base layer(s) in case of the insufficient compaction causing “alligatored” network-like cracking of asphalt pavement. 3. Proper technical and working conditions of the rehabilitated pavement during the nominal life cycle could be maintained by overlaying the surface treatment using bituminous emulsion materials or by single-pass overlaying a new hot-mixed asphalt concrete layer. Investigations accomplished during the implementation of HIR technologies allow enhance quality of recycled materials and also promote the entire adaptation of HIR technologies to the Ukrainian standards. Keywords: asphalt pavement rehabilitation, hot in-place recycling, recycled asphalt concrete, field testing, road pavement strength measurement, rutting measurement.

PARTICULARITIES OF HOT-IN-PLACE RECYCLING WITH CHANGING THE ASPHALT CONCRETE MIXTURE AGGREGATE GRADATION

The hot in-place recycling (HIR) belongs to the successful strategies of asphalt concrete pavements rehabilitation that provides effective elimination of such surface defects as cracking, rutting, stripping, raveling, and bleeding including defects caused by the non-conformity of asphalt concrete to the standard specifications. The HIR technologies are divided into four methods: «Reshape», «Repave», «Remix», and «Remix Plus». Among those methods, «Remix» and «Remix Plus» are more complicated technologically and are connected with changing the composition of existed (old) asphalt concrete. The composition of existed asphalt concrete should be corrected through the addition some of new components (aggregates, asphalt binder, rejuvenating agent, or new hot-mixed asphalt concrete mixture) to the hot-milled old asphalt layer. This article is dedicated to the methods of calculation of new and recycled aggregate mixture gradation regarding to the Ukrainian standards. The proposed methods of calculation consider such main peculiarities of HIR-recycled materials and layer design as: 1) old asphalt concrete, particularly its aggregate parts, can used in a non-fractioned form only; 2) HIR-recycled asphalt concrete layer should be designed with or without the maximal layer thickness restriction. The proposed methods also give the possibility to correct the technological process if the calculated amount of new material necessitated to the correction of old asphalt concrete aggregate grading does not allow to maintain the projected layer thickness. The implementation of the proposed technique of calculation of aggregate grading with and without restriction of the maximal thickness of recycled asphalt concrete layer allows enhance quality of recycled materials and promotes the entire adaptation of HIR technologies to the Ukrainian standards. Keywords: hot in-place recycling of asphalt concrete, «Remix», «Remix Plus», recycled asphalt concrete mixture, correction of aggregate gradation.

Cycles and sinks: two key elements of a circular economy

Modern products contain a wide range of substances. Some of them are hazardous, cause risks for human and environmental health, and impair the quality of future secondary resources produced by recycling. Ways must be explored to extract detrimental substances during recycling and direct them to safe final sinks. Final sinks can be end-of-pipe technologies (man-made sinks) or environmental media (natural sinks). The latter are limited in capacity and need to be protected against overloading. The paper presents a rationale for sinks in a circular economy, and supports decision-making regarding recycling materials with detrimental constituents. It is based on two case studies of regional flows of polycyclic aromatic hydrocarbons in spent asphalt pavements, and copper in waste flows. Applying a scenario approach, effective measures are discussed for circulating safe and high-quality materials while observing sink limitations. The results demonstrate the link between mass flows, quality of recycled material, and the need for final sinks. The optimization challenge of keeping cycles clean by costly measures for safe disposal of hazardous materials in sinks is discussed. Man-made sinks such as waste to energy plants and sanitary landfills are key for designing a circular economy that meets environmental and resource-oriented goals.

Towards a Sustainable Disassembly/Dismantling in Aerospace Industry

The quality of recycled material in a recycling process is actively influenced by an appropriate disassembly/dismantling strategy. In recycling the carcass of the aircraft, it is suitable to separate and classify different aluminum grades into their main alloys family before sending them to recycling center. However, due to complexity in the aircraft structure, fully disassembly/dismantling or fully shredding the aircraft is not economically or environmentally viable, respectively. For this reason, this work discusses eight different disassembly/dismantling strategies that have been done on a real Bombardier Regional Jet aircraft. The study proposes an approach to assess the sustainability influence of these strategies, as an important parameter that should be considered to select the most suitable strategy. This concept can be improved in order to be used in aerospace industry as an accurate method that allows to take the best decision depending on the concurrent situation.

Sustainability assessment of dismantling strategies for end-of-life aircraft recycling

With the current increase of environmental concerns, conventional methods practiced at end-of-life would not be capable to sustain the growing amount of retired aircrafts waiting for final disposal in the scrap yards each year. Material recycling is known as an important environmentally friendly activity. The quality of recycled material in a recycling process is actively influenced by an appropriate disassembly/dismantling strategy. In recycling the carcass of the aircraft, it is suitable to separate and classify different aluminum grades into their main alloys family before sending them to recycling center (i.e. 2xxx and 7xxx). However, due to complexity in the aircraft structure, fully disassembly/dismantling or fully shredding the aircraft is not economically or environmentally viable, respectively. For this reason, this work discusses eight different disassembly/dismantling strategies that have been done on a real Bombardier Regional Jet aircraft. The study narrows the gap in sustainability evaluation of these strategies by using an efficient fuzzy assessment method. Ten different risk scenarios were considered to have a robust understanding about the sustainability performance of each strategy. The methodology used in this work allowed to select the best strategy in terms of sustainable disassembly/dismantling.

종이팩의 재질ㆍ구조 개선을 위한 연구 - EPR 대상 품목을 중심으로 -

The carton for liquid products are divided into ‘gable top carton’ and ‘aseptic carton’. Currently, these packages are being recycled in the toilet tissue manufacturing process. The recycling of the carton aluminium laminate is the most important problem facing the recycling procedure of the carton packages due to the reduction in quality of recycled materials. The polymer structure with synthetic resins being used mainly in beverage packaging is also one of the important factors for the procedure for its recycling. The objective of this study was to investigate the package material and structure of the carton for liquid products through marketing research and suggest the supplementation in the work processes of production, use, and recycling. The results represent to improve the recycling profit and the quality of recycled materials when a laminated aluminium of carton for liquid products is replaced to the transparent polymer film. The improvement of the sorting and recycling process may help their recycling efficiencies. In addition, the limited use of synthetic resin molded packaging and increase of wood-pulp collection rate will provide the improvement of the recycling profit and the quality of recycled materials.

Fuzzy Assessment of Material Recyclability and Its Applications

A method to assess material recyclability using fuzzy logic is presented. Recyclability of materials is defined as a function of several variables, called basic indicators, which influence the technology and economics of the recycling processes, policies related to recycling, quality of recycled materials, and environmental impact of waste. Using a hierarchical network of fuzzy inference engines, the basic indicators are aggregated into more composite components of recyclability from which an overall recyclability measure is computed. A sensitivity analysis with respect to indicators identifies those components affecting the overall recyclability the most. Recyclabilities of three metals and three non-metals of high economic and industrial importance are assessed using this method.