Recycling Process Research Articles

Study into the reshaping process of large reservoir banks using remote sensing

Background. During the first 10—20 years after the creation of large reservoirs, the process of processing of coastal territories is activated, which leads to the loss of land resources, has a negative impact on the existing coastal infrastructure and changes in the depth of the reservoir as a result of activation of the process of rock accumulation, destruction of coastal slopes. Shoreline retreat is 10—15 meters per year. The paper considers the process of recycling of reservoir banks on the example of the Volgograd reservoir.Aim. Development of a methodology for studying and forecasting the process of reshaping of reservoir banks using remote sensing.Materials and methods. The data of 1980—1990 on the actual magnitude of bank reprocessing of the Volgograd reservoir were collected, processed and analyzed, and the coastal territory was typified. It is proposed to use remote sensing materials to obtain the values of coastal overbanking for the period from the 1990s to the present time. Forecasting of the process of reformation of reservoir banks is carried out on the basis of application of mathematical statistics methods.Results. On the basis of solving the set tasks, a universal new methodology for studying and forecasting reservoir bank reformation was proposed. The methodology was tested on the materials of the Volgograd reservoir.Conclusion. The proposed new methodology makes it possible to obtain data on the dynamics of the Volgograd reservoir bank reformation process and to make a forecast for the next 10 years. This methodology can be used to study the process of bank reformation of large reservoirs.

Expert Survey on the Impact of Cardboard and Paper Recycling Processes, Fiber-Based Composites/Laminates and Regulations, and Their Significance for the Circular Economy and the Sustainability of the German Paper Industry

Expert Survey on the Impact of Cardboard and Paper Recycling Processes, Fiber-Based Composites/Laminates and Regulations, and Their Significance for the Circular Economy and the Sustainability of the German Paper Industry

Safety assessment of the process Lietpak, based on the EREMA MPR technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Lietpak (EU register number RECYC327), which uses the EREMA MPR technology. The input material is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post-consumer PET containers, including no more than 5% PET from non-food consumer applications. The flakes are heated in a ■■■■■ reactor under vacuum. Having examined the challenge test provided, the Panel concluded that the ■■■■■ decontamination (step 2), for which a challenge test was provided, is critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of this step are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure a level of migration of potential unknown contaminants into food below the conservatively modelled migration of 0.1 μg/kg food, derived from the exposure scenario for infants, when such recycled PET is used at up to 100%. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long-term storage at room temperature or below, with or without hotfill. Articles made of this recycled PET are not intended to be used in microwave or conventional ovens and such uses are not covered by this evaluation.

Effective peroxymonosulfate activation by lithium cobaltite recovered from spent lithium-ion batteries for enhanced carbamazepine degradation in a wide pH range.

Considering the high cost and complicated recycling process of spent lithium-ion batteries (SLIBs), transforming SLIBs into environment functional materials may be a wise approach. Herein, lithium cobaltite (LCO) cathode powders recovered from SLIBs were used to activate peroxymonosulfate (PMS) for removing carbamazepine (CBZ). The recovered LCO enables a 98.2% removal efficiency of CBZ (2.5mg/L) within 10min, which was effective at a broader pH range (pH = 5.0-11.0). The influence of key factors (initial pH, PMS, and catalyst dosage) and coexisting substances (SO42-, H2PO4-, NO3-, Cl-, HCO3-, and HA) on CBZ degradation were examined in detail. The primary radical species during the degradation of CBZ were proved to be 1O2, SO4-, and.OH that generated from PMS activation initiated by the valence change of Co in recovered LCO. The recovered LCO displayed excellent reusability with about 80.0% removal of CBZ after six cycles. Homogeneous activation of PMS mainly contributed to CBZ degradation in the first run, but the recovered LCO catalyst dominated the heterogeneous activation of PMS for the degradation of CBZ in the second to sixth run. Finally, the CBZ degradation pathways were presented based on the identified intermediates. This research has offered a new strategy of "treating wastes with wastes" to maximize the recycling of electronic wastes to remove emerging pollutants.

Minimizing Pollution Effects through Recovery of Gases Thermal Energy from the Scrap Recycling Process

Minimizing Pollution Effects through Recovery of Gases Thermal Energy from the Scrap Recycling Process

Deep separation of Bi and Pb from leaching solution of molybdenite-bismuthinite mixed ore by solvent extraction method

A novel lead and bismuth deep-separation extraction-stripping system is proposed for the leaching solution of molybdenite-bismuthinite mixed ore, which creates perfect conditions for the preparation of high-purity bismuth-based materials. Based on the activity and ionic strength theories, the forms of bismuth and lead present in the solution were predicted according to the thermodynamic models of different systems. The results showed that N235 + 2-octyl alcohol + kerosene formed a synergistic extraction system, which realized the synergistic extraction of bismuth, iron and lead with solvent extraction ratios of 98.74 %, 9.34 % and 46.24 %, respectively. In addition, the FTIR spectra of bismuth and lead before and after extraction were recorded to better understand the extraction and vaporization mechanisms. When stripping with water, the stripping ratios of iron and lead were 99.87 % and 99.74 %, respectively, while the loss ratio of bismuth was only 0.01 %. In conclusion, this study will be a key link in the comprehensive recycling process of bismuth resources.

Sustainable Electrically Conductive Bio-Based Composites via Radical-Induced Cationic Frontal Photopolymerization.

Diglycidylether of vanillyl alcohol (DGEVA), in combination with mechanically recycled carbon fibers (RCFs), was used to make, via Radical-Induced Cationic Frontal Photopolymerization (RICFP), fully sustainable and bio-based conductive composites with good electrical conductivity and consequent Joule effect proprieties. Three different fiber lengths, using three different sieve sizes during the mechanical recycling process (0.2, 0.5, and 2.0 mm), were used in five different amounts (ranging from 1 to 25 phr). The samples were first characterized by dynamic mechanical thermal analysis (DMTA), followed byelectrical conductivity and Joule heating tests. More specifically, the mechanical properties of the composites increased when increasing fiber content. Furthermore, the composites obtained with the longest fibers showed the highest electrical conductivity, reaching a maximum of 11 S/m, due to their higher aspect ratio. In this context, the temperature reached by Joule effect was directly related to the electrical conductivity, and was able to reach an average and maximum temperatures of 80 °C and 120 °C, respectively, just by applying 6 V.

Packing simulation and analysis applied to a thermoplastic composite recycling process

A numerical model of packing applied to rigid objects is presented. It aims at describing a random stack of polymer composite chips in order to model the packing step of an existing recycling technique. The geometric properties of the stack play a major role in the mechanical properties of the recycled products. Short, simple and effective geometric descriptors of the stack are proposed. Their ability to differentiate random stacks is illustrated with an example. Then, a validation is proposed based on experimental data obtained from a bench specially designed for this work. The tests consist in the free fall of square chips. Finally, the developed model is compared to other models (free fall and packing of fibers) in order to enforce its relevance in the simulation of packing of rigid objects.

Early-stage recovery of lithium from spent batteries via CO2-assisted leaching optimized by response surface methodology

Recycling lithium (Li) from spent lithium-ion batteries (LIBs) due to the depletion of natural resources and potential toxicity is becoming a progressively favourable measure to realize green sustainability. Presently, the prevalent recycling technique relying on pyrometallurgy lacks the capability to extract lithium. Meanwhile, conventional hydrometallurgical processes frequently employ robust acidic solutions like sulfuric acid and precipitation agents such as sodium carbonate. Unfortunately, this approach tends to result in the extraction of lithium at the end of a lengthy process chain, leading to associated losses and creating challenges in managing complex waste. This study addresses a cost-effective and environmentally friendly early-stage lithium recovery from the thermally conditioned black mass. In this sense, a thermally conditioned black mass is subjected to the carbonization process in a water solution to transform the water-insoluble Li phase into soluble lithium bicarbonate (LiHCO3) and carbonate (Li2CO3) facilitating its selective separation from other elements. Response surface methodology (RSM)—a statistical tool integrated with central composite design (CCD) is employed to optimize the parameters for Li recovery. Temperature, solid–liquid (S/L) ratio, leaching time and CO2 flow rate are considered as variable factors in modelling the optimum recycling process. A quadratic regression model is developed for Li recovery and based on ANOVA analysis, (S/L) ratio, temperature and time are identified as statistically significant factors. Experimental results demonstrate a maximum leaching efficiency of lithium with optimized parameter set, achieving a recovery rate of 97.18% with a fit response of 93.54%.

E-WASTE MANAGEMENT THROUGH DEEP LEARNING: A SEQUENTIAL NEURAL NETWORK APPROACH

The goal of this research is to improve the management of electronic trash (e-waste) by using a Sequential Neural Network (SNN) with TensorFlow and Keras as part of an advanced deep learning technique. In order to address the growing problem of e-waste, the research collects a large amount of data from images of e-waste and then carefully preprocesses and augments those images. With precision, recall, and F1 scores of 87%, 86%, and 86%, respectively, the SNN architecture—which incorporates dropout, pooling, and convolutional layers—achieved an amazing 100% classification accuracy. These outstanding outcomes show how well the model can classify e-waste components, suggesting that it has the potential to be used in real-world scenarios. The results indicate that the SNN-based approach greatly improves the accuracy and efficiency of e-waste sorting, promoting environmental sustainability and resource conservation. By automating the sorting process, the suggested system decreases the need for manual labor, minimizes human error, and speeds up processing. The study emphasizes the model's suitability for integration into current e-waste management workflows, providing a scalable and dependable way to expedite the recycling process. Additionally, the model's real-time applicability highlights its potential to revolutionize current e-waste management practices, making a positive ecological impact. . Future research endeavors will center on broadening the dataset to include a wider range of e-waste image categories, investigating more advanced deep learning architectures, and incorporating the system with Internet of Things (IoT) devices to improve real-time monitoring and management.

Multi-perspective evaluation on spent lithium iron phosphate recycling process: For next-generation technology option

The recycling of spent lithium iron phosphate batteries has recently become a focus topic. Consequently, evaluating different spent lithium iron phosphate recycling processes becomes necessary for industrial development. Here, based on multiple perspectives of environment, economy and technology, four typical spent lithium iron phosphate recovery processes (Hydro-A: hydrometallurgical total leaching recovery process; Hydro-B(H2O2/O2): hydrometallurgical selective lithium extraction process; Pyro: Pyrometallurgical recovery process; Direct: Direct regeneration process) were compared comprehensively. The comprehensive evaluation study uses environment, economy and technology as evaluation indicators, and uses the entropy weight method and analytic hierarchy process to couple the comprehensive indicator weights. Results show that the comprehensive evaluation values of Hydro-A, Hydro-B (H2O2), Hydro-B (O2), Pyro and Direct are 0.347, 0.421, 0.442, 0.099 and 0.857, respectively. Therefore, the technological maturity of Direct should be further improved to enable early industrialization. On this basis, this study conducted a quantitative evaluation of the spent lithium iron phosphate recycling process by comprehensively considering environmental, economic and technical factors, providing further guidance for the formulation of recycling processes.

Recycling and Reutilization of Metals Aided by Deep Eutectic Solvents: from NMC Cathodes of Spent Li-ion Batteries to Electrolytes for Supercapacitors.

With the rapidly increasing demand for lithium ion batteries (LIBs), recycling the metals found in spent cathodes is mandatory to both alleviate shortages resulting from the mining of natural metal ores and manage the disposal of spent LIBs. The use of deep eutectic solvents (DESs) for metals recovery from spent cathodes of LIBs (e. g., LCO and NMC types) offers a sustainable yet efficient alternative to conventional hydrometallurgical processes. Nonetheless, g efforts are required to use milder temperatures and higher mass loadings, thus ensuring cost-effectiveness. In this latter regard, addressing the reutilization of DESs in subsequent stages of metal extraction, and streamlining or eliminating the chemical procedures employed for metal separation, is even more crucial to guarantee the economic feasibility of the recycling process. Herein, we have prepared a DES that provides extraction efficiencies of ca. 100 % for every metal of NMC cathodes even at mild experimental conditions (e. g., 60 °C) and for loadings as high as 70 mgNMC/gDES. Moreover, we have pioneered the direct use of leachates containing DESs and metals as electrolytes for supercapacitors. This approach enables the reintroduction of DESs and the recovered metals into the value chain with a minimal economic and environmental impact.

Electrochemical technology to drive spent lithium-ion batteries (LIBs) recycling: recent progress, and prospects

The widespread use of lithium-ion batteries (LIBs) in recent years has led to a marked increase in the quantity of spent batteries, resulting in critical global technical challenges in terms of resource scarcity and environmental impact. Therefore, efficient and eco-friendly recycling methods for these batteries are needed. The recycling methods for spent LIBs include hydrometallurgy, pyrometallurgy, solid-phase regeneration, and electrochemical methods. Compared to other recycling methods, electrochemical methods offer high ion selectivity and environmental friendliness. Assembling research on the recycling and reutilization of spent LIBs, with a focus on the various electrochemical techniques that can enhance these processes, is essential. A thorough analysis of the characteristics and evolution of these methods remains crucial to advancing the field of electrochemical technology in battery recycling. This review first discussed the necessity of recycling spent LIBs from multiple perspectives and briefly introduced the main pyrometallurgical and hydrometallurgical recycling technologies, analyzing their advantages and disadvantages. Moreover, we comprehensively summarized the current applications of electrochemical technology in the recycling of spent LIBs, including pretreatment, leaching, element separation, and regeneration. Then, we analyzed the characteristics and advantages of different electrochemical techniques in the LIB recycling process and discussed the obstacles encountered in the application of electrochemical technology and their solutions. Finally, a comparison between electrochemical technology and traditional recycling processes was provided, highlighting the potential advantages of electrochemical technology in reducing recycling costs and minimizing waste emissions.

Closed-Loop Recycling of Mixed Plastics of Polyester and CO2-Based Polycarbonate to a Single Monomer.

Physical blending is an effective strategy for tailoring polymeric materials to specific application requirements. However, physically blended mixed plastics waste adds additional barriers in mechanical or chemical recycling. This difficulty arises from the intricate requirement for meticulous sorting and separation of the various polymers in the inherent incompatibility of mixed polymers during recycling. To overcome this impediment, this work furthers the emerging single-monomer - multiple-materials approach through the design of a bifunctional monomer that can not only orthogonally polymerize into two different types of polymers - specifically lactone-based polyester and CO2-based polycarbonate - but the resultant polymers and their mixture can also be depolymerized back to the single, original monomer when facilitated by catalysis. Specifically, the lactone/epoxide hybrid bifunctional monomer (BiLO) undergoes ring-opening polymerization through the lactone manifold to produce polyester, PE(BiLO), and is also applied to ring-opening copolymerization with CO2, via the epoxide manifold, to yield polycarbonate, PC(BiLO). Remarkably, a one-pot recycling process of a BiLO-derived PE/PC blend back to the constituent monomer BiLO in >99 % selectivity was achieved with a superbase catalyst at 150 °C, thereby effectively obviating the requirement for sorting and separation typically required for recycling of mixed polymers.

Closed‐Loop Recycling of Mixed Plastics of Polyester and CO2‐Based Polycarbonate to a Single Monomer

AbstractPhysical blending is an effective strategy for tailoring polymeric materials to specific application requirements. However, physically blended mixed plastics waste adds additional barriers in mechanical or chemical recycling. This difficulty arises from the intricate requirement for meticulous sorting and separation of the various polymers in the inherent incompatibility of mixed polymers during recycling. To overcome this impediment, this work furthers the emerging single‐monomer – multiple‐materials approach through the design of a bifunctional monomer that can not only orthogonally polymerize into two different types of polymers – specifically lactone‐based polyester and CO2‐based polycarbonate – but the resultant polymers and their mixture can also be depolymerized back to the single, original monomer when facilitated by catalysis. Specifically, the lactone/epoxide hybrid bifunctional monomer (BiLO) undergoes ring‐opening polymerization through the lactone manifold to produce polyester, PE(BiLO), and is also applied to ring‐opening copolymerization with CO2, via the epoxide manifold, to yield polycarbonate, PC(BiLO). Remarkably, a one‐pot recycling process of a BiLO‐derived PE/PC blend back to the constituent monomer BiLO in >99 % selectivity was achieved with a superbase catalyst at 150 °C, thereby effectively obviating the requirement for sorting and separation typically required for recycling of mixed polymers.

Concentration of Silver from Recycling of Fine Powder of Wasted Videogame Printed Circuit Boards through Reverse Froth Flotation and Magnetic Separation Processes

Electronic waste stream grows day by day; printed circuit boards are a kind of solid waste that accounts for 6% of electronic waste. When these are discarded, they can cause soil, water, and air contamination; however, if recycled, these can be considered as a secondary source of metals. Physical comminution of printed circuit boards generates particles with sizes smaller than 250 µm, which are typically not included in the recycling process because they are considered as dust and unvaluable; nevertheless, precious and base metals can be found in these particles. The concentration of metals like silver, among others, from these particles can be achieved by reverse froth flotation in a flotation column followed by magnetic separation of the tails products. A mass balance of the flotation column feed, concentrate, and tails indicates that using a pulp modified with 5 ppm methyl isobutyl carbinol plus 5 g/ton oleic acid (both biodegradable reagents), the concentration of the products improved, resulting in recoveries of 86.13 and 13.87% in the concentrate and tails zones, respectively, with a grade of 74.4% in the tails flow. Magnetic separation of the tails product increases slightly the concentration of silver, reaching a silver grade of 74.5%, a recovery amount similar to those obtained employing complex and environmentally unfriendly processes.

Assessment of the Quantities of Non-Targeted Materials (Impurities) in Recycled Plastic Packaging Waste to Comply with EU Regulations and Sustainable Waste Management

Plastic packaging waste (PPW) can be considered as solid waste with harmful effects on the environment or as a material with recycling potential in terms of sustainable development in a circular economy. Knowing the amount of PPW generated is very important as it is related to the availability of this material for recycling and determines the actual recycling rate (denominator of a fraction). PPW is very heterogeneous and contains a certain number of impurities (e.g., product residues, direct printing, glue, labels, plastic sleeves, cap, etc.). According to EU law, an annual report (for the data in 2021) on the masses of both the PPW actually recycled (PPWR) (“targeted materials”) and impurities (“non-targeted materials”) must be prepared and submitted to the European Commission. The PPWR is used for the calculation of the recycling rate (the numerator in a fraction). The impurities should be considered for the calculation of own resources (national contributions to the general EU budget based on the uniform call rate of 0.80/kg of non-recycled PPW). To date, the Council of the EU has not proposed a method for calculating these amounts, so they have only been estimated. The present study (the first of its kind in Poland) aimed to estimate the number of impurities in PPW and the actual amount of PPWR at the calculation point using a method accepted by the EU. In the installations, PPW (plastic packaging (15 01 02), multi-material packaging (15 01 05) and mixed packaging waste (15 01 06)) is recycled together with other plastic waste (plastic (16 01 19), plastic (17 02 03), plastic and rubber (19 12 04), and plastics (20 01 39)). It was assumed that the proportions of the mass of individual types of PPW in the total mass of plastic waste processed in the installation were proportional to the mass of impurities in these individual types of PPW. It was found that the average percentage of impurities in PPW was 4.40–6.90%, which seems to be relatively low. However, this means that, when calculating the PPWR, the mass of impurities should be subtracted from the mass of PPW entering the recycling process. As a result, the mass of PPWR at the calculation point in 2021 in Poland was almost 30,000 tonnes lower than the original mass entering the installation. Thus, applying the uniform call rate to the weight of impurities in the PPW increases Poland’s own resources by approx. 24 million euros.

Environmental impact assessment of the manufacture and use of N- type and P-type photovoltaic modules in China

For a long time, solar power has been considered a clean and non-polluting energy source because it absorbs sunlight without consuming other energy or materials and does not emit pollutants. Nevertheless, the manufacturing and end-of-life stages of solar power systems leave an environmental footprint and produce pollutants. Hence, a global perspective on photovoltaic (PV) systems using life cycle assessment methodology is necessary. Here, we investigated the life cycle impacts of P- and N-type PV modules in terms of their energy consumption, carbon emissions, and human toxicity potential. In addition, the energy payback durations of P- and N-type PV modules were computed. In this study, we used the Life Cycle Assessment Basic Database from the National Engineering Laboratory of Industrial Big Data Application Technology at Beijing University of Technology to create a life cycle assessment model for N-type PV modules. Subsequently, we performed a life cycle assessment of Chinese silicon N-type- and P-type PV modules. The research system encompassed the production processes for metallic silicon materials, solar-grade silicon materials, silicon wafers, cells and modules, utilization, recycling, and other interrelated processes. We found that the production and processing of silicon-to-solar-grade polysilicon feedstock were crucial stages that significantly affected the energy consumption and environment of P- and N-type PV modules in China. The high electricity consumption of this process, combined with the dominance of coal power in China's electricity structure, contributed to the substantial energy consumption and environmental impacts of the PV modules. Therefore, this stage is critical for the low-carbon and environmentally sustainable manufacturing of N-type PV modules in China. Carbon emissions for both the P-type and N-type PV modules were lower only during the cell production phase but higher during the other stages when compared to the P-type and N-type PV modules. The n-type bifacial PV modules yielded the highest return on investment in terms of energy. Different regions and installation types have a substantial impact on the carbon emissions of P-type and N-type PV modules. Projections indicate that the potential to lower carbon emissions from n-type PV modules will increase by 2060.

A closer look at lithium-ion batteries in E-waste and the potential for a universal hydrometallurgical recycling process

The demand for lithium-ion batteries (LiBs) is rising, resulting in a growing need to recycle the critical raw materials (CRMs) which they contain. Typically, all spent LiBs from consumer electronics end up in a single waste stream that is processed to produce black mass (BM) for further recovery. It is desired to design a recycling process that can deal with a mixture of LiBs. Hence, this study investigates the structure and composition of battery modules in common appliances such as laptops, power banks, smart watches, wireless earphones and mobile phones. The battery cells in the module were disassembled into cell casing, cathode, anode and separator. Then, the cathode active materials (CAMs) were characterized in detail with XRD-, SEM-, EDX- and ICP-OES-analysis. No direct link was found between the chemistry of the active materials (NMC, LCO, LMO, LFP etc.) and the application. Various BM samples were submitted to a leaching procedure (2 M H2SO4, 50 °C, 2 h, 60 g BM/L) with varying concentration (0–4 vol%) of H2O2 to study the influence of their chemical composition on the dissolution of Li, Ni, Mn and Co. Only a part of the BMs dissolved completely at 4 vol% H2O2, which was attributed to the oxidation state of the transition metals (TMs). Exact determination of H2O2 consumption by redox titration confirmed this hypothesis.

An effective tandem leaching method for recovering precious metals from depleted ternary lithium-ion batteries

The increasing volume of spent ternary lithium batteries necessitates the development of an environmentally friendly and efficient recycling process tailored for these batteries. This paper introduces an innovative leaching system that employs oxalic acid and its derivative, Deep Eutectic Solvents (DES), as leaching agents, specifically designed to selectively recover Li and other valuable metals from the cathode materials of discarded ternary lithium batteries, Li(NixCoyMn1-x-y)O2 (NCM). These findings indicate that oxalic acid is capable of selectively leaching Li without the need for reducing agents, whereas DES effectively segregates and leaches other valuable metals. The optimal parameters determined through orthogonal experiments for the initial leaching stage included a solid-to-liquid ratio of 15 g L−1, leaching duration of 3 h, temperature of 75 °C, and stirring speed of 400 rpm, resulting in a Li leaching rate of 99.95%. In the subsequent step, DES enabled the precipitation of Ni and the leaching of Co and Mn within 2 h at 110 °C, achieving recovery rate of 99.88% for Ni, 98.1% for Co, and 90% for Mn, while also significantly optimizing the recovery conditions. This breakthrough may offer an environmentally benign and effective method for the selective recovery of Li and other valuable metals.