Recycling Of Components Research Articles

Deep learning-based construction and demolition plastic waste classification by resin type using RGB images

The construction and demolition sector generates a substantial portion of Australia's total waste, with plastics being a key recyclable component. The perceived financial impracticality of sorting and separating waste, coupled with the simplicity of landfilling processes often contribute to mixed material loads sent directly to landfills. Therefore, developing a commercially feasible system that can accurately separate the generated waste is imperative. This paper presents a comprehensive study on using RGB images for deep learning-based construction and demolition plastic waste classification by resin type. A large and specialised dataset of end-of-life plastic waste images is gathered. This dataset comprises four commonly used plastic types in construction projects—ABS, HDPE, PS, and PVC. Leveraging Transfer Learning with models pre-trained on ImageNet, highly accurate models tailored to this classification task are developed in this paper. Advanced Convolutional Neural Network and Vision Transformer-based models, including ResNet, ResNeXt, RegNet, and Swin Transformer, are trained and evaluated on this dataset. Another contribution of this work is Knowledge Distillation from a large, computationally intensive, and accurate model to enhance the accuracy of fast and compact models specifically designed for deployment on edge devices. This study applies Knowledge Distillation by using the output class probabilities of the large, computationally intensive Swin Transformer model to enhance the accuracy of the fast and lightweight MobileNetV3 models. The results demonstrate that RGB images offer a practical alternative to other costly and complex systems for effective plastic identification, due to their availability, low cost, ease of use, simple setups, and robustness to variations in operational conditions.

Circular economy: Extending end-of-life strategies

The transition from linear economy to circular economy (CE) has gained mainstream status in recent times, not only at product and process levels, but also at component level. In order to adopt the CE as common practice, there is a need to reimagine the product end-of-life (EoL) phase to include assessment of individual component health status. Implementation of EoL strategies on products designed based on wear and tear, robustness, and safety concerns is, however, complex. The purpose of this study is to explore the potential of designing for CE by applying a visual health-based analysis (VHA) at the component level at the EoL stage. The application of this diagnostic tool is exemplified in a case at a large Swedish outdoor power product manufacturer by analyzing components for reuse, remanufacture, refurbishment, recycling, and recovery strategies. The VHA results in the calculation of a CE potential at the component-product level based on individual component's cost, complexity, health, and diagnostic approach. This study presents a diagnostic tool for practitioners to understand circularity at the component-level in the effort to identify EoL strategies. Furthermore, in supporting the CE principle of maximizing resource recovery, the study potentially contributes to the EU's CE action plan and the UN-SDGs 8, 9, 12, and 13.

Oxygen and silicon isotopic compositions of Archean silicified lava and cherts of the Onverwacht Group: Implication for seafloor hydrothermalism and the nature of recycled components in the source of granitoids

Cherts are commonly used as proxies for Archean environmental conditions such as oceanic temperature. However, because cherts encompass a wide variety of silica-rich rocks, including post-depositional silicified of clastic sediments or chemical precipitates from seawater, reconstructions of the Archean environment based on their O and Si isotopic compositions remain controversial. In this study, we present triple O isotope analyses associated with SIMS O and Si isotope measurements of Palaeoarchean pervasively silicified lavas and clastic sediments, which have been less studied than the associated cherts within the Onverwacht Group (Barberton Greenstone Belt, South Africa). We also provide triple O isotopic compositions of seawater-precipitated cherts. The O and Si isotope composition of silicified clastic sediments and lavas is not considerably variable through the Onverwacht succession. These lithologies display relatively low δ18O (11.3–14.9 ‰) and high Δ’17O values (−0.05 to - 0.07 ‰) attributed to precipitation of silica from hydrothermal fluids at lower temperatures than 200 °C. Using these results, we reconstruct the approximate O isotope composition of the hydrothermal fluids. Water-rock interaction models suggest that this fluid composition is consistent with the existence of low δ18O oceans, but the exact δ18O value of the Palaeoarchean ocean remains elusive. Seawater-precipitated cherts show a mixture of hydrothermal and seawater-like triple O isotope signatures, confirming that cherts are not a straightforward proxy for constraining Archean seawater composition or temperature. The average δ30Si value of the pervasively silicified lavas and clastic sediments is positive (> +0.19 ‰) and compositionally similar to published values of the seawater-precipitated cherts. This suggests comparable δ30Si values between Archean hydrothermal fluids and seawater. A gradual increase of δ18O values of silicified lavas and cherts from 10 to 13 ‰ to 15–20 ‰ observed along the Onverwacht succession is ascribed to local lithospheric cooling occurring between 3.47 Ga and 3.3 Ga, while Si isotope compositions remained mostly unchanged in the silica-rich rocks. As silicified lavas are likely part of materials that melted to generate Palaeoarchean granitoids, the evolutional difference between O and Si isotopes may have characterised the silicified rocks that were recycled in different generations of granitoid sources. This may explain the variation in O isotopic compositions measured in different granitoid generations in the Barberton area.

Bulk Rock and Olivine Chemistry and Isotopes of 106–58 Ma Basalts from Liaodong Peninsula and its Adjacent Areas: Implications for Secular Evolution of the Big Mantle Wedge in Eastern China

Abstract The subducting Pacific slab stagnates in the mantle transition zone and creates a big mantle wedge (BMW) system in East Asia. A similar BMW structure may have already existed since the Early Cretaceous (>120 Ma), but how such a structure evolved from Early Cretaceous to the present day remains unclear. We address this issue by comparing compositions and source heterogeneity of the 106–58 Ma basalts from Liaodong Peninsula and its adjacent areas (LPAA) in eastern China, with those formed in the modern BMW setting. The LPAA basalts display oceanic island basalts–like trace element patterns. Elemental and isotopic compositions of these basalts and their olivine phenocrysts point to peridotite and two recycled components in their source. One recycled component is altered lower oceanic crust given the low δ18Oolivine (2.8–5.2‰) of the ~99 Ma Liaoyuan alkali basalts. The second component consists of altered upper oceanic crust and pelagic sediments indicated by high δ18Oolivine (>6.0‰), represented by the ~58 Ma Luanshishanzi alkali basalts. The depleted mantle-like isotopes of these two components suggest derivation from a young HIMU source with characteristics of the Izanagi plate (e.g. Indian Ocean-type Sr-Nd-Pb-Hf isotopes), which may have resided in the mantle transition zone at that time. Our results reveal strong similarities between chemical and source characteristics of the mantle sampled by the 106–58 Ma LPAA basalts and those derived from the modern BMW. This implies that the BMW structure has been present since the Early Cretaceous, probably having lasted more than 120 Myr, and modulating the chemical properties of the upper mantle and influencing a variety of geological processes.

CLUH maintains functional mitochondria and translation in motoneuronal axons and prevents peripheral neuropathy.

Transporting and translating mRNAs in axons is crucial for neuronal viability. Local synthesis of nuclear-encoded mitochondrial proteins protects long-lived axonal mitochondria from damage; however, the regulatory factors involved are largely unknown. We show that CLUH, which binds mRNAs encoding mitochondrial proteins, prevents peripheral neuropathy and motor deficits in the mouse. CLUH is enriched in the growth cone of developing spinal motoneurons and is required for their growth. The lack of CLUH affects the abundance of target mRNAs and the corresponding mitochondrial proteins more prominently in axons, leading to ATP deficits in the growth cone. CLUH interacts with ribosomal subunits, translation initiation, and ribosome recycling components and preserves axonal translation. Overexpression of the ribosome recycling factor ABCE1 rescues the mRNA and translation defects, as well as the growth cone size, in CLUH-deficient motoneurons. Thus, we demonstrate a role for CLUH in mitochondrial quality control and translational regulation in axons, which is essential for their development and long-term integrity and function.

Nitrogen recycling characteristics in multiphase transformation during municipal sludge pyrolysis

The nitrogen content of municipal sludge is as high as 2.5～9.0 wt%, which has become an important problem in pollution control during pyrolysis. Recycling nitrogen from municipal sludge not only enables resource utilization, but also reduces the nitrogen-related pollution. In this study, the transformation pathways of nitrogen to resource material and typical pollutants during the municipal sludge pyrolysis process were analyzed. The results showed that the nitrogen species in municipal sludge were mainly protein-N (64.41%), pyridine-N (19.47%) and inorganic-N (16.13%). After pyrolysis at 300 °C, the peptide bond of protein-N was gradually broken down, resulting in the formation of three nitrogenous intermediates (amine-N, nitrile-N and heterocyclic-N) were produced. These intermediates can be transformed to NH3 for resource recovery or to HCN pollutants. Moreover, the full nitrogen transformation pathways of municipal sludge pyrolysis were constructed by the method of Spearman's correlation coefficient and experiment analysis. It was found that NH3 and HCN were mostly generated from the cracking of three nitrogenous intermediates at 600–800 °C. In addition, there was a prominent effect on the transformation of HCN to NH3 with co-presence of calcium minerals in raw sludge. By adding inorganic calcium minerals, NH3 as a recyclable component was prominently improved by 10.30% at 700 °C, while HCN yield was decreased by 53.02% accordingly under the inhibitory effect. The results systematically provided a theoretical support to the possibility of nitrogen recycling for utilization during municipal sludge pyrolysis, as well as to control the transformation of nitrogen elements into pollutants.

Acrylonitrile‐butadiene‐lignin thermoplastic rubber adhesive for enhanced metal‐to‐metal joining

AbstractWith the growing requirement for lightweight structural materials in automotive, aerospace, and infrastructure applications, multi‐material joints made with adhesive have attracted intense research interest. Commercial thermoset adhesives are one‐time cures, and difficult to disassemble the bonded components for repair and recycling. Our prior work with a thermoplastic acrylonitrile‐butadiene‐lignin rubber (ABL) addresses this sustainability/recycling challenge, but the adhesive exhibits deficient joining strength compared to standard thermosets. Here, we modify the ABL matrix by loading particulate fillers to enhance its modulus and toughness. The goal is to manufacture a cure‐free thermoplastic adhesive system with a simple dispensing protocol and characteristic ductility combined with a high yield stress for improved shear strength of a bonded joint. Fumed silica (FS) and epoxidized glass spheres (EGS) were used as fillers in the ABL to promote the dispersion of lignin particles that tailored the functionalities and free energy components of the adhesive surface. With optimal loading of FS (5 wt%) and EGS (30 wt%) in the ABL adhesive matrix, the lap‐shear strength of the bonded aluminum joint was elevated by 128%, compared to the neat ABL, reaching 21 MPa, which is 90% of the performance of a commercial epoxy‐based adhesive.Highlights A partly renewable filler‐toughened thermoplastic adhesive has been developed. This thermoplastic gives nearly equivalent performance of adhesively bonded aluminum joint compared to standard thermosets. Experimental and simulation data help understand the adhesive reinforcing mechanism by the fillers.

Morphology Distribution in Injection Molded Parts.

A more sustainable use of plastic parts makes it necessary to replace current plastic parts with recyclable components, also allowing the modulation of the part properties through the process. Injection molding is one of the most widely used technologies for obtaining rigid plastic parts, so it is crucial to understand how to tailor properties by adopting the correct processing conditions. One way is to perform annealing steps directly inside the mold: in-mold annealing improves the structural integrity and durability of the material, reduces defects, increases the resistance of parts against certain chemicals, reduces wear and tear, increases ductility, and lowers brittleness. In this work, several in-mold annealing steps were conducted, changing the mold temperature and annealing duration selected on the basis of the half crystallization time of the adopted isotactic polypropylene. The typical molded part morphology, composed of oriented layers at the surface, transition zones, and spherulitic core, is strongly affected by in-mold annealing. In particular, the thickness of the oriented layer, which forms in the early phase of the process, decreases, and the spherulites increase in size. Concerning mechanical behavior, the orientation degree mostly determines the elastic modulus value close to the surface, whereas the conditions under which crystallization occurs determine the modulus in the core.

Characterisation of the Grain Morphology of Artificial Minerals (EnAMs) in Lithium Slags by Correlating Multi-Dimensional 2D and 3D Methods

Slags from the metallurgical recycling process are an important source of resources classified as critical elements by the EU. One example is lithium from Li-ion battery recycling. In this context, the thermodynamic properties of the recycled component system play a significant role in the formation of the Li-bearing phases in the slag, in this case, LiAlO2. LiAlO2 crystal formation could be engineered and result in varying sizes and occurrences by different metallurgical processing conditions. This study uses pure ingredients to provide a synthetic model material which can be used to generate the valuable phase in the slag, or so-called engineered artificial minerals (EnAMs). The aim is to investigate the crystallisation of LiAlO2 as an EnAM by controlling the cooling conditions of the model slag to optimise the EnAM formed during crystallisation. Characterisation of the EnAMs is an important step before further mechanically processing the material to recover the valuable element Li, the Li-bearing species, respectively. Investigations are conducted using powder X-ray diffraction (XRD), X-ray fluorescence (µXRF), and X-ray Computer Tomography (XCT) on two different artificial lithium slags from MnO-Al2O3-SiO2-CaO systems with different cooling temperature gradients. The result shows the different EnAM morphology along the height of the slag, which is formed under different slag production conditions in a semi-pilot scale experiment of 5 kg. Based on the different EnAM morphologies, three defined qualities of the EnAM are identified: granular, dendritic, and irregular-shape EnAM.

Implementing BIM and Lean Construction Methods for the Improved Performance of a Construction Project at the Disassembly and Reuse Stage: A Case Study in Dezhou, China

The construction industry is adopting a collaborative paradigm by combining Lean construction (LC) principles and BIM capabilities. Existing studies lack sufficient case studies and performance evaluations, especially for the disassembly and reconstruction stage, creating a gap in the practical application of BIM and Lean construction (BIM-LC) in China. To bridge this gap, this study quantitatively assessed the BIM-LC methodology in a relocation project in Dezhou, China. The project employed BIM-LC practices such as the Last-Planner System (LPS), Just-In-Time (JIT), Kanban, Value-Stream Mapping (VSM), and Continuous Improvement to enhance construction efficiency and minimize waste. Two main areas of the relocation process were investigated: (i) the identification of common barriers and on-site solutions to the implementation of BIM-LC; (ii) evaluation of the construction efficiency, construction and demolition waste (CDW), and carbon-emission performance. The results showed that the BIM-LC strategy improved labor efficiency and productivity by 3.4% and 12.9%, shortened the construction period by 11 days, reduced construction costs by 8.07% (i.e., USD 9093.8), and reduced transportation costs by 12.5% (i.e., USD 1875). The CDW generation rate ranged from 1–5%, which is comparable to the rates observed in residential construction across various countries. The total weight was 1903.8 kg (10.4 kg/m2). Moreover, the carbon emission during the relocation process was 15,288.4 kgCO2e, with a carbon intensity of 83.5 kg/m2. This study extends the knowledge systems on the application of the BIM-LC method in relocation projects and supports data-driven decision making. It also plays a crucial role in fostering new markets for recycled components, contributing to the realization of a sustainable built environment.

СТРАТЕГИЧЕСКИЕ ОРИЕНТИРЫ РАЗВИТИЯ ПРОМЫШЛЕННЫХ ПРЕДПРИЯТИЙ ДОНБАССА

The work highlights the guidelines for the development of the industrial complex of Donbass, through alternative economic and organizational tools of technological progress, allowing, in the context of the restoration of industrial enterprises of the Donetsk People’s Republic (hereinafter referred to as the DPR), the development of progressive forms of production organization (PFOP) and advanced management methods. An analysis of the existing practice of the considered areas of the organizational, economic and technical level of the industrial potential of Donbass made it possible to outline the concept of a comprehensive solution for the synthesis of production structures at the stages of reconstruction and technical re-equipment of production. The methodological basis is generally accepted in economic science methods of scientific analysis and synthesis, induction and deduction, generalization, comparison. The paper presents the results of analytical studies of an important component of the scientific and technical potential of industrial sectors of Donbass, which have significant untapped internal potential for activating and restoring its economic and technological structure to a higher neo-industrial competitive level. The main strategic guidelines for the development of industrial enterprises in Donbass are outlined, including: a) the creation of the Unified Fund for the Development of Science and Technology (EDFST); b) development of mini-factories on unused production areas of MMK im. CM. Kirov and Azovstal Iron and Steel Works; c) optimization of business processes of iron-containing components for resource recycling; d) development of progressive forms of production organization and innovative technologies.

RECYCLING AND UPCYCLING IN THE ELECTRO-MECHANICAL DOMAIN: A REVIEW OF CURRENT PRACTICES

This study provides a comprehensive review of current practices, challenges, and future prospects in recycling and upcycling within the electro-mechanical domain, with a particular focus on the role of recyclable electronic components in sustainable system design. The primary objectives were to assess the effectiveness of existing recycling techniques, explore innovative upcycling approaches, and evaluate the integration of recyclable components in system design. The methodology employed a systematic literature review, drawing data from peer-reviewed journals, industry reports, and government publications. Key databases such as IEEE Xplore, ScienceDirect, and Google Scholar were utilized, with a focus on literature published between 2018 and 2023. The findings revealed that while current recycling techniques are effective, they face technical and economic barriers that hinder widespread adoption. Upcycling approaches show promise in enhancing the value and utility of electro-mechanical systems. The integration of recyclable electronic components is pivotal for sustainability, though it requires more efficient recycling processes and innovative design strategies. Emerging technologies, such as IoT and AI, offer potential solutions but are underexplored in practical applications. The study concludes that sustainable practices in the electro-mechanical domain significantly impact environmental conservation and resource management. However, supportive policy and regulatory frameworks are crucial for enhancing these practices. Future research should focus on developing more efficient recycling techniques, exploring the economic viability of sustainable practices, and integrating emerging technologies. Addressing these areas is essential for advancing sustainability in the electro-mechanical domain.
 Keywords: Recycling, Electromechanical systems, Upcycling, Sustainable Design.

TRANSPORT SUPPORT OF METALLURGICAL PRODUCTION WASTE RECYCLING

Purpose. One of the possible ways to improve the efficiency and environmental friendliness of metallurgy is processing and reuse in production as raw material of iron-containing dusty waste. At the same time, an integral component of such waste recycling is the transportation of iron-containing dust from the sources to the granulation areas, where it is processed. However, existing technological solutions for dust transportation are characterized by significant dust generation both during loading-unloading operations and during transportation. In this regard, the paper considers dust-free transportation technology for dusty waste using tank containers. Methodology. During the research, methods of geospatial analysis of transportation routes, taking into account dimensional and weight restrictions, methods of planning the operation of motor vehicles on routes, methods of the theory of shunting work on railway transport were used. Results. The work on the application of one of the metallurgical enterprises presents the methodology for determining the required fleet of vehicles and the main technical and technological parameters of schemes for the iron-containing dust transportation in tank containers by road and rail transport. Scientific novelty. The obtained research results on transport process parameters allow to perform scientific and economic justification of choosing a technological scheme for the transportation of dust waste. Practical significance. The presented technological schemes can be used as solutions for the transportation support of recycling iron-containing dusty waste in metallurgical production.

Utilization of all components of waste concrete: Recycled aggregate strengthening, recycled fine powder activity, composite recycled concrete and life cycle assessment

Waste concrete can be crushed to produce a large amount of recycled aggregate(RA) and recycled fine powder(RFP). Different recycled components have different characteristics. RA should focus on its pretreatment method, while RFP should focus on its morphology and volcanic ash activity. This study investigated the effects of two single and composite strengthening methods in RA, mechanical vibration and acid solution immersion. The results showed that the composite strengthening method was more effective in improving the properties of RA, which resulted in an increase in apparent density and bulk density by 5.59 % and 12.55 %, respectively, and a decrease in crush value and water absorption by 26.05 % and 15.52 %, respectively. Three methods were used to analyze the volcanic ash activity of RFP with different particle sizes, and the RFP with a particle size of 23.08 μm has a high volcanic ash activity, which can effectively play its role of filling and volcanic ash activity in recycled concrete. Based on the preferred pre-treated RA and RFP, the effect of RA and RFP on the macroscopic and microscopic properties of recycled concrete under different mixing amounts was studied, and the results showed that the compressive strength of 20 % RA single mixing could reach 40.17 MPa, and that the compressive strength of 20 % RFP single mixing could reach 38.6 MPa, and both of them had no significant effect on the frost resistance. Further, 20 % RA and 20 % RFP were compounded to prepare recycled concrete, and the results showed that the compressive strength of RA-RFP was slightly improved to 40.12 MPa, and the mechanism of its action was explained by microscopic analysis. Finally, the environmental impact and carbon emission reduction of the life cycle of RA and RFP were evaluated, and the results showed that the utilization of recycled materials can play an effective environmental benefit.

Spatial Computer Model of the UCl<sub>3</sub>–NaCl–MgCl<sub>2</sub>–PuCl<sub>3</sub> Isobaric Phase Diagram

A four-dimensional (4D, in concentration–temperature coordinates) computer model of the isobaric phase diagram of uranium, sodium, magnesium, and plutonium chlorides, as well as four three-dimensional (3D) computer models of the phase diagrams of the ternary systems forming it, has been constructed. The technology of assembling a 4D model of 46 hypersurfaces and 17 phase regions was used in the design. The obtained 4D model of the UCl3–NaCl–MgCl2–PuCl3 phase diagram makes it possible to visualize a four-dimensional object as a whole (with all its hypersurfaces and phase regions) by any arbitrarily given 2D and 3D sections, as well as it is able to reproduce published (experimental or thermodynamically calculated) 2D sections. The scope of application of the results of the work is the development of materials for fuel components of fourth-generation molten salt reactors and pyrochemical recycling of spent fuel rods. For the first time, a comprehensive, complete description of phase diagrams composed of uranium, plutonium, sodium, and magnesium chlorides has been obtained.

Polystyrene carbon composite foam with enhanced insulation and fire retardancy for a sustainable future: Critical review

Polystyrene (PS) composite foams are an intriguing class of materials that are well established for thermal insulation in construction and lightweight recyclable components in automotives. Research has shown the remarkable properties of these foams in terms of thermal and sound insulation and fire retardancy that can be enhanced by incorporating carbon fillers such as graphite, graphene, and biochar. Several methods have been examined by researchers to mix carbon with the polystyrene matrix and prepare PS carbon composite foams, which can broadly be categorized into suspension polymerization, solution mixing and melt blending. These methodologies along with foaming techniques for the expansion of PS using various blowing agents are reviewed. We also review the most relevant research studies in the field of PS carbon composite foams for insulation (thermal and sound) and fire retardancy. Due to its high infrared radiation absorption capacity and hetero nucleating action, expandable graphite and graphene can lead to excellent thermal and sound insulation along with fire retardancy in a PS foam, thus resulting in significant energy savings in a building. Biochar, due to its inherent low thermal conductivity and nucleating action, modifies the foam morphology, leading to enhanced heat and sound absorption and thus is a low-cost renewable carbon alternative that promotes the circular economy.

The N-terminus of Spt16 anchors FACT to MCM2-7 for parental histone recycling.

Parental histone recycling is vital for maintaining chromatin-based epigenetic information during replication, yet its underlying mechanisms remain unclear. Here, we uncover an unexpected role of histone chaperone FACT and its N-terminus of the Spt16 subunit during parental histone recycling and transfer in budding yeast. Depletion of Spt16 and mutations at its middle domain that impair histone binding compromise parental histone recycling on both the leading and lagging strands of DNA replication forks. Intriguingly, deletion of the Spt16-N domain impairs parental histone recycling, with a more pronounced defect observed on the lagging strand. Mechanistically, the Spt16-N domain interacts with the replicative helicase MCM2-7 and facilitates the formation of a ternary complex involving FACT, histone H3/H4and Mcm2 histone binding domain, critical for the recycling and transfer of parental histones to lagging strands. Lack of the Spt16-N domain weakens the FACT-MCM interaction and reduces parental histone recycling. We propose that the Spt16-N domain acts as a protein-protein interaction module, enabling FACT to function as a shuttle chaperone in collaboration with Mcm2 and potentially other replisome components for efficient local parental histone recycling and inheritance.

Separation and recovery of zinc from blast furnace dust via coordination leaching of Cl− and hydrolysis of NH4+

Blast furnace dust (BFD) is a by-product of iron-making process, a typical hazardous waste containing abundant recyclable components. In this study, a NH4Cl cooperative coordination leaching method was proposed for the selective separation and recovery of zinc from BFD. The thermodynamic analysis results revealed that ZnO and ZnSO4 from BFD can be converted to zinc-chlorine coordination compounds (ZnCli2−i, i = 1,2,3,4) in the cooperative actions of NH4+ and Cl− ions. The experimental results showed that the leaching efficiency of zinc reached 85.64% while iron and carbon was enriched from 46.76% to 57.96% under the optimal experimental conditions. The leaching residue with a total content 2.53% of Zn, Cl, K and Na can be returned to sintering for the recovery of iron and carbon. Moreover, the XRD, SEM-EDS and chemical phase analysis results of BFD and residue demonstrated that a small amount ZnO, ZnS and ZnFe2O4 were not leached and remained in the leaching residue. Additionally, a novel method of low-temperature crystallization was adopted to recover zinc from filtrate. The crystallization efficiency of zinc reached 80.96% and the obtained crystal was confirmed to be special Zn(NH3)2Cl2. Thus, this work not only achieved the separation and recovery of zinc from BFD, but also solved the disposal problem of leaching residue and crystallization solution, providing a guidance for the resource utilization of hazardous BFD.

Analysis of element yield, bacterial community structure and the impact of carbon sources for bioleaching rare earth elements from high grade monazite

Rare earth element (REE) recovery from waste streams, mine tailings or recyclable components using bioleaching is gaining traction due to the shortage and security of REE supply as well as the environmental problems that occur from processing and refining. Four heterotrophic microbial species with known phosphate solubilizing capabilities were evaluated for their ability to leach REE from a high-grade monazite when provided with either galactose, fructose or maltose. Supplying fructose resulted in the greatest amount of REE leached from the ore due to the largest amount of organic acid produced. Gluconic acid was the dominant organic acid identified produced by the cultures, followed by acetic acid. The monazite proved difficult to leach with the different carbon sources, with preferential release of Ce over La, Nd and Pr.

Investigating a closed-loop dual-channel green supply chain with stochastic demand rate and collection ratio using the distribution-free approach

This paper investigates a dual-channel closed-loop supply chain in an uncertain market environment consisting of a manufacturer, a retailer, and a collector, where the manufacturer can produce green products by utilizing recycling components from the collector and raw materials from an outside source. According to our analysis, market demand is stochastic and strongly influenced by channels’ selling prices, the level of green innovation, and retail service. Additionally, the collection rate of used-obsolete products is also random and affected by green innovation levels and refund prices. We analyze the model by dividing it into three scenarios based on players’ collaborative and non-collaborative behavior and then solve the problem in centralized and decentralized cases through a distribution-free approach. Using vertical Nash and Stackelberg game approaches, the interaction between players is modeled in the decentralized scenario. The model’s findings are illustrated with a numerical example, and a sensitivity analysis is also performed to provide insights into management by determining how different parameters will impact profits. Results suggest that the higher expected value of demand randomness is linked to increased market scale but that random variables with higher variance levels are more uncertain, leading to lower channel profitability. Moreover, a collaborative effort between manufacturer and collector could improve both prices and greenness, ultimately boosting the fraction collected. In addition, results reveal that the retailer Stackelberg frameworks will most adversely affect players, whereas the manufacturer Stackelberg frameworks will generate profits almost every time.