Thermodynamic Principles in Materials Recycling

… for the materials recycling process. The focus will be on the separation of materials from a mixture. This problem can be modeled using the principles of thermodynamics, particularly the …

… recycling of the recovered material streams from end-of-life vehicles (ELVs) were described. From the thermodynamics … This article proposes a thermodynamics-based model for the …

… thermodynamics associated with the manufacture of automobiles, both from new raw materials and from recycled … " raw materials, the amounts of thermodynamic potential consumed in …

… One may apply the concepts of thermodynamics to the recycling problem. The First Law is concerned with the conservation of energy and relates to the environmental goal of …

… of thermodynamics and … recycling rates from a large range of primary concentrates and recyclates. However, the 2nd Law of Thermodynamics teaches us the practical limits of recycling …

Abstract Current metal recycling techniques for end-of-life vehicles (ELV) are based on mechanical treatments to mainly recover steel, aluminum, copper, and zinc alloys. Such techniques facilitate compliance with the ELV European Directive (2000/53/EC) target of achieving recyclability quotes of up to 85%. However, a vehicle can use more than 60 metals, some of them considered critical by international institutions, which end up downcycled as part of alloys or ultimately in landfills. This paper undertakes an assessment of the downcycling degree of minor metals in conventional vehicles using a SEAT Leon III model as a case study. Downcycling is assessed from a thermodynamic point of view using thermodynamic rarity, an indicator that is used as a weighting factor for the metals used in the car. The thermodynamic rarity of metals is a function of the quality of the minerals from which they stem, considering their relative abundance in Nature and the energy intensity required to extract and process them. The results demonstrated that, even if the quantity of downcycled metals only represents 4.5% of the total metal weight of the vehicle, in rarity terms, this figure increases to approximately 27%. This indicates that an important portion of high-quality metals becomes functionally lost. The most downcycled vehicle subsystems are in order: (1) accessories, (2) electrical and electronic equipment, (3) exhaust system, and (4) engine. Further, the most downcycled parts are: speed sensor, control unit, antenna amplifier, airbag circuit, temperature and rain sensors, front pipe, particle filter, and turbo parts.

… At this same level of thinking about the chemical thermodynamics, one recognizes that the final … Both the thermodynamics and kinetics of the chemical system determine the boundary …

… (EPR) have made recycling an important responsibility. … material, which is hard to leach in the recovery process, hence, needs a chemical pretreatment. In this study, thermodynamics …

… 5 —Material and product-centric recycling and design for recycling rules and digital methods, Design for Recycling (DfR) demands the use of tools that can quantify a product’s recycling …

This paper presents a thermodynamic vision of the depletion of mineral resources. It demonstrates how raw materials can be better assessed using exergy, based on thermodynamic rarity, which considers scarcity in the crust and energy requirements for extracting and refining minerals. An exergy analysis of the energy transition reveals that, to approach a decarbonized economy by 2050, mineral exergy must be greater than that of fossil fuels, nuclear energy, and even all renewables. This is because clean technologies require huge amounts of many different raw materials. The rapid exhaustion of mines necessitates an increase in recycling and reuse, that is, a “circular economy”. As seen in the automobile industry, society is far removed from closing even the first cycle, and absolute circularity does not exist. The Second Law dictates that, in each cycle, some quantity and quality of materials is unavoidably lost (there are no circles, but spirals). For a rigorous recyclability analysis, we elaborate the exergy indicators to be used in the assessment of the true circularity of recycling processes. We aim to strive toward an advanced economy focused on separating techniques and promoting circularity audits, an economy that inspires new solutions: an in-spiral economy.

… On the basis of chemical thermodynamics, this study quantitatively demonstrated the limit of removal of impurity elements during the aluminum remelting process. It also suggests that …

… With the increasing demand of Mg alloys, their recycling will become an important issue in the near future. In the current study, the chemical reactions involved during the recycling …

This paper makes a review of current raw material criticality assessment methodologies and proposes a new approach based on the second law of thermodynamics. This is because conventional methods mostly focus on supply risk and economic importance leaving behind relevant factors, such as the physical quality of substances. The new approach is proposed as an additional dimension for the criticality assessment of raw materials through a variable denoted “thermodynamic rarity,” which accounts for the exergy cost required to obtain a mineral commodity from bare rock, using prevailing technology. Accordingly, a given raw material will be thermodynamically rare if it is: (1) currently energy intensive to obtain and (2) scarce in nature. If a given commodity presents a high risk in two of the three dimensions (economic importance, supply risk, and thermodynamic rarity), it is proposed to be critical. As a result, a new critical material list is presented, adding to the 2014 criticality list of the European Commission (EC) Li, Ta, Te, V, and Mo. With this new list and using Sankey diagrams, a material flow analysis has been carried out for Europe (EU‐28) for 2014, comparing the results when using tonnage and thermodynamic rarity as units of measure. Through the latter, one can put emphasis on the quality and not only on the quantity of minerals traded and domestically produced in the region, thereby providing a tool for improving resource management.

… Furthermore, it is often the case that certain “scaling effects” suggested by thermodynamics … what Thermodynamics says about four important recycling questions: 1) What gets recycled?, …

… The minimum work required for a prescribed separation in a reversible process is easily … For binary component systems which form ideal solutions, this minimum work requirement …

… The copper can be recycled with minimal contamination, and the … separation is generally preferable to microscopic separation. … the need for separation at the atomic or molecular level. …

This paper explores the limits of recycling on a fundamental basis. This fundamental basis suggests that the high recycling quotas for end-of-life vehicles (ELVs) as required by EU …

… We analyse the individual local entropies in definitions of the entropy of mixing. … entropy of mixing by considering an alternative “total entropy” that is based on the “per-species entropies…

PurposeThe paper attempts to address both resource consumption and recycling effectiveness, using concepts from thermodynamics: entropy production for evaluating the costs (resource consumption) and statistical entropy for evaluating the benefits (separation of materials) of recycling processes.Design/methodology/approachResource consumption, in this context, is to be understood as the overall thermodynamic devaluation of matter and energy flows. The recycling effectiveness, on the other hand, can be measured by the process's ability to reduce the “mixedness” of the material flows, using statistical entropy (entropy of mixing) as an indicator. Statistical entropy has been used by others as an indicator for the performance of waste separation processes, and its application to metal recycling seems straightforward. Entropy production has been applied as a measure for resource consumption in copper production. Here, the two concepts are combined to reach an expression describing the resource efficiency of recycling.FindingsThe theoretical description of the approach is supported by an example calculation for copper recycling. The findings suggest a near perfect effectiveness of the copper separation when processing medium grade copper scrap in a primary copper smelter. The resource consumption, on the other hand, is quite large when compared to the service of the process, giving rise to a rather small thermodynamic efficiency (in terms of the definition of efficiency as applied in this paper).Research limitations/implicationsBoth measures used here, recycling efficiency and recycling effectiveness, are very demanding concerning the data basis, making applications time consuming. These drawbacks can be overcome by linking material flow tools (e.g. LCA software) with thermodynamic databases. More examples have to be considered to show the practical relevance of the approach.Originality/valueThe paper addresses effectiveness and efficiency using a common denominator, thermodynamic entropy. This unification helps in ranking different recycling options regarding their performance in terms of technical effectiveness and resource consumption.

… applied to quantify changes in statistical entropy (SE). … entropy reductions (ΔH METALS =−16.3% and ΔH METALS =−23.8% in two optimised cases), reflecting enhanced metal recovery …

… -solvent mixing, but (3) as it now stands, does not take this into account [8]. Finally, in as much as (3) represents a normalized entropy measure of mixing, any energy barriers for mixing …

… associated with the recovery of complex, multicomponent, waste mixtures. Moreover, the definition of entropy used in the present work is strictly physical (the entropy of mixing), not …

Abstract The second law of thermodynamics, through exergy analysis, is commonly applied to quantify process inefficiencies in metallurgical reactors, however, it has not yet been used to understand physical processes and changes in particle-based systems. Correlating the state of mixing of particle texture and homogeneous liquid mixtures is of importance. This paper applies the exergy analysis and excess entropy method to two sets of experiments highlighting the differential breakage as microwave pre-treatment is applied to a gold-copper ore. Grinding kinetic properties were measured following the top-size fraction method and calculated using the population balance model. The approach combines the mixing entropy on the system level (streams) and the entropy for multicomponent particle systems, using automated mineralogy data to quantify the effects of intergrowth and improvements in grinding performance. This is a first step towards understanding mineral processing not only in terms of energy conservation (first law of thermodynamics) but also in terms of the quality of energy available at multicomponent systems (second law of thermodynamics). When applied to comminution processes, this methodology enables us to understand the change in particle composition (its degree of liberation) as well as changes in particle size, being an important measure of process efficiency and selectivity.

Abstract In a circular economy (CE), materials, components and products should be kept at the highest level of functionality, while phenomena like dilution, mixing and contamination, often referred to as the loss of resources, should be avoided. One method that can assess the performance of systems to concentrate or avoid dilution of resources is Statistical Entropy Analysis (SEA). Up till now, the method has been applied on the substance level (elements and compounds) only, but showed its applicability to various scales and a variety of systems. Further development of the method allowed to consider information on the product, component and material levels, which makes the method applicable to different combinations of CE strategies, both destructive (e.g. recycling) and non-destructive (e.g. reuse). The method is demonstrated on a simplified vehicle life-cycle, which is modeled through four component groups and six materials. It shows that the method allows to evaluate different CE strategies and identify critical stages which lead to the most severe resource and functionality losses. Based on the method's results, it is possible to determine a perfect circularity reference level, representing a system state that preserves functionality and avoids resource losses. The introduction of a circularity reference level enables the establishment of a framework for resource effectiveness in which diluting and concentrating effects of activities (e.g. sorting) are quantified. The distance of a system to an ideal circular state determines the deviation from a resource-effective system that maintains the original product functionality over a maximum period of time, with minimal efforts.

… phase destruction, thereby generating high-entropy mixed phases that are difficult to separate and recover. Guided by the minimum entropy production principle, 25 this work pioneers a …

… material mixtures from divergent origins or with very different make-up. This work develops an approach using statistical entropy with a multi-level material … , material mixing complexity is …

… results of chemical thermodynamic analysis on the distribution … This study results in thermodynamic features of various … efficiency should be expected, except for lead and tin in …

… suitably optimized for the efficient recovery of desired elements … In this study, a thermodynamic analysis was performed to … of the method by applying it to study the recycling of end-of-life …

… the sustainability of technological options is thermodynamic life-cycle approach. Whereas, the … The thermodynamic analysis of a life cycle shows a cumulative loss of exergy due to the …

… calculations were then carried out to analyze the sulfuration … Thermodynamic analysis showed that the products of tin and … verify the reliability of the thermodynamic analysis, with good …

… In the Kroll process, the low efficiency and high energy consumption of the batch operations make the thermochemical processes … Therefore, the recycling of titanium metal is crucial. …

Waste plastics contribute to serious environmental and social problems, such as the loss of natural resources, environmental pollution, and depletion of landfill space, but they also create demands on the environmentally-oriented part of the society. Feedstock recycling of scrap polymers by thermal and chemical methods is well known and environmentally accepted. The paper presents the results of thermodynamic analysis of the conversion of polyolefins in a fuel-like mixture of hydrocarbons using thermal cracking in a new type of tubular reactor with molten metal. Evaluation of the efficiency of the process was based on exergy calculations. Calculated exergy efficiency was ca. 79.5 %. It means that feedstock recycling of waste is better from an energetic and environmental point of view than other processes, particularly incineration.

… Exergy is used to describe recycling efficiency of complex … thermodynamics to be able to estimate this in real-time during design. Hence, all material properties and thermodynamics are …

… thermodynamic analysis of processing of electronic waste (e-waste), particularly printed circuit boards (PCB), through secondary copper recycling (… of secondary copper recycling with (…

The removability of impurities during the aluminum remelting process by oxidation was previously investigated by our research group. In the present work, alternative impurity removal with chlorination has been evaluated by thermodynamic analysis. For 43 different elements, equilibrium distribution ratios among metal, chloride flux and oxide slag phases in the aluminum remelting process were calculated by assuming the binary systems of aluminum and an impurity element. It was found that the removability of impurities isn’t significantly affected by process parameters such as chloride partial pressure, temperature and flux composition. It was shown that Ho, Dy, Li, La, Mg, Gd, Ce, Yb, Ca and Sr can be potentially eliminated into flux by chlorination from the remelted aluminum. Chlorination and oxidation are not effective to remove other impurities from the melting aluminum, due to the limited parameters which can be controlled during the remelting process. It follows that a proper management of aluminum scrap such as sorting based on the composition of the products is important for sustainable aluminum recycling.

… efficiency as an indicator for the resource efficiency of the recycling chain. In this paper exergy analysis is added as a metric to the fundamental recycling system optimisation model …

… In this study, exergy analysis was applied to four residual household waste management … exergy flow analysis (higher efficiencies were associated with high levels of material recycling), …

… A practical difficulty of exergy analysis is that it requires the definition of a reference state. A characteristic of the natural systems is that the reference state is particularly difficult to define …

… For this purpose exergy analysis is used. This tool incorporates changes in both mass and quality of materials during recycling. Exergy analysis requires thermodynamical knowledge …

… Recycling n times results in PE with an exergy content: with RF as the recycled fraction (kg of recycled … In conclusion, we have shown that exergy analysis of industrial metabolisms can …

Decision‐makers should strive for an efficient employment of resources for the whole industrial ecological system. The metabolization of resources should be optimized in thermodynamic terms. This contribution presents an effort to use exergy analysis as a quantitative tool in the thermodynamic optimization of the life cycle of plastics. Quantitative results on overall exergetic efficiencies of different industrial metabolic options are presented. Therefore, different waste treatment options of plastics will be considered, taking into account interacting industrial activities, such as virgin plastics production and heat and electricity production starting from natural resources. Copyright © 2004 John Wiley & Sons, Ltd.

… an exergy analysis can be used to evaluate an IWM. … , exergy analysis provides information on how the energy of UCO upgraded to biodiesel throughout the IWM and identifies material …

… to quaternary recycling. This research suggests that the application of exergy analysis into the … procedures in the automotive sector, this study uses a thorough exergy analysis. Based on …

In the last century, the economic growth has been accompanied by a worldwide diffusion of polymers for multiple applications. However, there is a growing attention to the environmental pollution and energy consumption linked to the unconditional use of plastic. In the present work, exergy is used as a measure of the resource consumption during the life cycle of polymers. Nine commercially diffused polymers are chosen, and their production chains are identified according to the “grave to cradle” approach. The global Embodied Exergy (EE) is calculated as the sum of the contribution of each step of the chain, including the production process and the Exergy Replacement Cost (ERC) of the fossil fuel. Then, recycling routes and the associated exergy consumption are analysed. Thermodynamic recycling indexes are developed depending on the final product, namely the crude polymeric material and the oil derivatives or structural molecules. The main results show that some commonly used polymers have a considerable impact in terms of EE (e.g., PET). Recycling indexes encourage the recycling processes, which are always energetically convenient (from 10% to 60% of exergy savings) compared with the production from virgin raw material. Results from EE calculation are used for the thermodynamic assessment of the plastic content of vehicle components, to obtain useful information for recycling practices development.

The increase of waste presents a challenge for organizations and societies pursuing sustainable development. In this context, recycling is widely recognized for being a friendly strategy to the environment and the proper approach to effectively manage waste and minimize the negative impact on the environment and the economy. However, since the available recycling technology requires both raw materials and energy, it ultimately contributes to the depletion of natural resources. Therefore, it is vital to assess the energy efficiency of recycling processes to determine their real benefit. The scientific literature suggests a series of approaches, requirements and practices, which may be, at first sight, confusing. The present study focuses on efficiency evaluation of recycling processes by means of exergetic analyses. It performs a systematic review, based on nine significant factors in recycling processes, of the relevant literature concerning the evaluation of recycling processes through the exergetic approach. The review makes two important contributions. First, it presents an approach for assessing such diverse literature by means of a single structure. In addition, it allows the identification of improvement opportunities and reveals future research opportunities.

… , information theory and systematology. Thus, they cannot account for the irreversibility of separation … way to reveal the evolution that separation systems undergo in order to make solute …

… that total recycling is impossible for an industrial society as a consequence of the second law of … the sun) for a stable steady-state recycling system to function. The paper also discusses (…

A comparison is presented of the main approaches to second-law analysis (SLA) reported in the literature. Five SLAs are considered: exergy, physical-exergy, exergy-consumption, negentropy and entropy analyses. The application of the SLAs is illustrated through an example. In addition, several significant implications of SLA are examined in the fields of environmental impact and economics. The presentation herein of the approaches to and implications of SLA is expected to enhance understanding of SLA and improve its usefulness. Copyright © 1999 John Wiley & Sons, Ltd.

… principles such as the second law of thermodynamics, as well as … recycling system over time. Including these real-world details and constraints enables realistic comparisons of recycling …

Thermodynamic equilibrium model and second law analysis of a downdraft waste gasifier - ScienceDirect …

… Second Law and GR‘s Law: if the Fourth Law is accepted into the framework of physics, then the Second Law … In conclusion, complete recycling is physically possible if a sufficient …

… We discuss how thermodynamics can help (1) prioritize and design circularity 21 strategies, (2) avoid partial fixes, problem-shifting and rebounds, and (3) develop a systematic 22 …

ABSTRACT Material flow analysis (MFA) is the main methodology to assess material flow circularity. It is essentially a data-analysis-based approach whose physical foundations consist of conservation of mass. To improve both the accuracy and the repeatability of MFA models, in this paper we leverage compartmental dynamical thermodynamics merged with graph theory and control theory. The key idea is that the thermodynamic compartments and their connections can be added, removed or modified as needed to achieve a circular material flow. Thus, our methodology consists of designing thermodynamical material networks (TMNs). We also provide a physics-based definition of circularity and implement a nonlinear compartmental control, which has been possible since TMNs are highly dynamic models based on differential calculus (i.e. ordinary differential equations) rather than on arithmetic as is typical for MFA models. As we envision scalable and repeatable designs of TMNs, we made publicly available the paper source code.1

Circular economy's (CE) noble aims maximize resource efficiency (RE) by, for example, extending product life cycles and using wastes as resources. Modern society's vast and increasing amounts of waste and consumer goods, their complexity, and functional material combinations are challenging the viability of the CE despite various alternative business models promising otherwise. The metallurgical processing of CE-enabling technologies requires a sophisticated and agile metallurgical infrastructure. The challenges of reaching a CE are highlighted in terms of, e.g., thermodynamics, transfer processes, technology platforms, digitalization of the processes of the CE stakeholders, and design for recycling (DfR) based on a product (mineral)-centric approach, highlighting the limitations of material-centric considerations. Integrating product-centric considerations into the water, energy, transport, heavy industry, and other smart grid systems will maximize the RE of future smart sustainable cities, providing the fundamental detail for realizing and innovating the United Nation's Sustainability Development Goals.

… science understands that the limits posed by the Second Law of Thermodynamics are real and non- negotiable. The increase in entropy – ie the degradation of any material or form of …

… Ultimately, the flow of materials and their implicit energy in the circular economy (CE) … thermodynamics. These laws quantify the losses in the circular economy system in terms of material…

… and objective methods to evaluate their flows of mass and materials. In the last century, Howard T. Odum used thermodynamics to calculate the exergy of resource flows. He started …

… handling of materials merely shift … material and energy flows in linear and circular economies and a deeper understanding of the practical limits to circularity imposed by thermodynamics …

Circular economy aims at decoupling human activities from resource use and creating wealth. However, many have questioned the link between increased circularity and sustainability, resulting in several methodological approaches being developed to answer that question. This article analyzes and discusses the insights gained from applying agent‐based modeling and simulation to study the techno‐economic and social conditions promoting circularity and sustainability. This article analyzes the benefits and limitations of this technology and discusses future methodology developments within the circular economy context. Moreover, six limits of the circular economy concept are used to interpret insights from the literature: thermodynamic limits, system boundary limits, limits posed by the physical scale of the economy, limits posed by path dependencies and lock‐in, limits of governance and management, and limits of social and cultural definitions. Promising research avenues are to use this methodology with machine learning, industrial ecology methods, and detailed geographic information.

… we use this knowledge to study the circularity of the economy?” … to check the level of circularity of the economic flows in a … thermodynamics, complex patterns of energy and material …

… acute circularity barriers due to alloy complexity and degradation risks. In contrast, more chemically stable metals such as copper do not experience the same thermodynamic limitations …

… the carbon emissions and material circularity for an internal combustion engine … thermodynamic limits that will prevent 100% closed loops. This limit is referred to as the theoretical limit…