Search Results (63)

Hospitals often use diatrizioic acid (DTZA), an iodinated radiocontrast agent, which is poorly biodegradable and persistent in aqueous media. Therefore, the objective of this work is to remove DTZA from water using an advanced separation process, namely liquid surfactant membrane (LSM) or emulsion liquid membrane. The LSM system is composed of Aliquat 336 as extractant, Span 80 as emulsifier, kerosene as diluent, and KCl as internal stripping phase. The impacts of experimental parameters impacting the extraction of DTZA from water by LSM, namely surfactant concentration, initial pH of the contaminated solution, extractant dosage, nature of base in the contaminated solution, concentration of the internal stripping phase, nature of stripping solution, emulsion/external solution volume ratio, internal solution/organic phase volume ratio, mixing rate, nature of diluent, emulsification time, emulsification rate, and initial DTZA concentration, were investigated. A highly stable emulsion with a good degree of removal of 90.8% of DTZA in water was obtained for an emulsifier dosage of 3% (w/w), an extractant dosage of 1.0% (w/w), a pH of the contaminated solution of 10 using NH₄OH, a concentration of the inner phase of 0.3 N KCl, an internal solution/organic phase volume ratio of 1/1, an emulsion/external solution volume ratio of 20/250, a mixing speed of 250 rpm, an emulsification time of 4 min, and an emulsification speed of 20,000 rpm. Additionally, the extraction of DTZA from various natural water matrices (natural mineral water, tap water and seawater) was examined. The developed LSM method offers a fascinating enhanced separation method for the elimination of DTZA in waters with low chloride ion concentrations. Full article

The synergistic effect of using D2EHPA and TOPO together to enhance the extraction of samarium(III) from aqueous media via emulsion liquid membrane (ELM) technology was explored. D2EHPA in binary mixtures with TBP and in ternary mixtures with TOPO and TBP was also tested. Among the tested extractants, a binary mixture of 0.1% (w/w) D2EHPA and 0.025% (w/w) TOPO achieved 100% samarium(III) extraction at a low loading. This mixture outperformed D2EHPA-TBP and other systems because D2EHPA strongly binds to Sm(III) ions, while TOPO increases the solubility and transport efficiency of metal complexes. Additionally, process factors that optimize performance and minimize emulsion breakage were examined. Key insights for successfully implementing the process include the following: 5 min emulsification with 0.75% Span 80 in kerosene at pH 6.7 (natural), 250 rpm stirring, a 1:1 internal/membrane phase volume ratio, a 20:200 treatment ratio, and a 0.2 N HNO₃ stripping agent. These insights produced stable, fine droplets, enabling complete recovery and rapid carrier regeneration without emulsion breakdown. Extraction kinetics accelerate with temperature up to 35 °C but declined above this limit due to emulsion rupture. The activation energy was calculated to be 33.13 kJ/mol using pseudo-first-order rate constants. This suggests that the process is diffusion-controlled rather than chemically controlled. Performance decreases with Sm(III) feed concentrations greater than 200 mg/L and in high-salt matrices (Na₂SO₄ > NaCl > KNO₃). Integrating these parameters yields a scalable, low-loading ELM framework capable of achieving complete Sm(III) separation with minimal breakage. Full article

Heat treatment is a critical intermediate process in copper strip manufacturing, where strips go through an air-cushion annealing furnace. The production scheduling for the air-cushion annealing furnace can contribute to cost reduction and efficiency enhancement throughout the overall copper strip production process. The production scheduling problem must account for time window constraints and gas atmosphere transition requirements among jobs, resulting in a complex combinatorial optimization problem that necessitates dual-objective optimization of the total atmosphere transition cost of annealing and the total penalties for time window violations. Most multi-objective optimization algorithms rely on the evolution of a single population, which makes them prone to premature convergence, leading to local optimal solutions and insufficient exploration of the solution space. To address the challenges above effectively, we propose a Bi-population Co-evolutionary Multi-objective Optimization Algorithm (BCMOA). Specifically, the BCMOA initially constructs two independent populations that evolve separately. When the iterative process meets predefined conditions, elite solution sets are extracted from each population for interaction, thereby generating new offspring individuals. Subsequently, these new offspring participate in elite solution selection alongside the parent populations via a non-dominated selection mechanism. The performance of the BCMOA has undergone extensive validation on benchmark datasets. The results show that the BCMOA outperforms its competitive peers in solving the relevant problem, thereby demonstrating significant application potential in industrial scenarios. Full article

This study investigates the optimization of an ammonia-based leaching process for the recovery of lithium and cobalt from spent LiCoO₂ cathodes, coupled with an energy-efficient ammonia stripping approach. Kinetic analysis revealed that both lithium and cobalt extraction follow pseudo-first-order kinetics, with activation energies of 76.54 kJ/mol and 97.22 kJ/mol, respectively, indicating a chemically controlled process. Optimal leaching conditions were established at 6 M NH₃, 1.5 M (NH₄)₂CO₃, liquid-to-solid ratio of 10:1, and 70 °C for 5 h, achieving 82.5% lithium and 96.1% cobalt recovery. The ammonia stripping process was optimized for energy efficiency, with operations at 95–98 °C providing the best balance between rapid NH₃ removal and energy consumption. At 98 °C, energy demand was reduced to ~282 kJ/mol, a sevenfold improvement over lower temperature operations. A stepwise separation strategy was developed, involving selective lithium precipitation at pH 10.7–10.8, followed by controlled ammonia stripping to precipitate cobalt at pH 8.8–9.0. This integrated approach offers a promising alternative to conventional acid-based recycling methods, combining high metal recovery with improved energy efficiency and reagent recyclability. Full article

This systematic study was conducted on the separation of yttrium (Y) and erbium (Er) from a chloride medium using a mixed extractant system composed of [N1444][P507] and TRPO (trialkylphosphine oxide) in kerosene. This investigation focused on the effects of various extractants, extraction systems, the initial acidity of the aqueous phase, and the phase contact time on the extraction efficiencies of Y and Er. This study showed that using the combination of [N1444][P507] and TRPO notably increased the extraction performance and enhanced the separation factor between Y and Er, outperforming the individual use of P507 or [N1444][P507] under identical conditions. The extraction efficiencies for Y and Er reached 88.4% and 93.3%, respectively, with a separation factor (Er/Y) of 1.84, highlighting the system’s effectiveness in selectively isolating rare earth elements. Optimal stripping conditions were obtained using 0.1 mol/L of HCl, resulting in a successful recovery of 93.1% of Y³⁺ and 78.9% of Er³⁺ from the organic phase. The extraction mechanism involved both ion exchange and ion association. The enthalpy changes (ΔH) associated with the extraction of Y³⁺ (−2.5 kJ·mol⁻¹) and Er³⁺ (4.6 KJ·mol⁻¹) demonstrate that the extraction processes are exothermic, reflecting the thermodynamic differences between the two ions. Full article

Efficient removal of iron and aluminum impurities is critical for the extraction of lithium and rubidium from zinnwaldite, a lithium-bearing mineral. In this study, solvent extraction using P507 was employed to remove iron and aluminum from zinnwaldite leaching solutions. However, stripping iron from the organic phase proved challenging due to the strong interaction between iron ions and the extractant. To address this, a novel reduction stripping method was developed using ascorbic acid (AA) as a reductant. This method exploits the reduction of Fe³⁺ to Fe²⁺ in the aqueous phase, weakening the binding between iron ions and the organic phase, thus enabling efficient stripping. The optimized process achieved over 99.99% removal of iron and aluminum impurities. Subsequently, rubidium was selectively extracted using t-BAMBP, with a total recovery rate of 88.53%. Scaling-up experiments confirmed the feasibility of the process for industrial applications, demonstrating high efficiency and reagent recyclability. This study offers a promising approach for the efficient extraction and separation of valuable metals from zinnwaldite, with potential for broader applications in metal processing. Full article

With the rapid growth of the lithium-ion battery (LIBs) market, recycling and re-using end-of-life LIBs to reclaim the critical Li, Co, Ni, and Mn has become an urgent task. Presently, high temperature, strong acid, and alkali conditions are required to extract blended critical metals (CM) from the typical battery cathode. Hence, there is a need for more effective recycling processes for recycling blended Li, Co, Ni, and their direct regeneration for re-use in LIBs. The goal of the offered paper is the development of recycling technology for degraded battery cathode-active materials based on the thermal decomposition of polyvinylidene fluoride (PVDF) using calcination and air-jet stripping of active materials. The proposed air-jet erosion method of calcined cathode material stripping from Al foil allows for the flexible industry-applicable separation process, which is damage-free for both particles and substrate. The CaO calcination air-jet separation process and equipment can significantly improve the PVDF decomposition and the separation efficiency of the cathode materials. It is demonstrated that low-temperature CaO calcination at 350–450 °C associated with air-jet separation of active material is characterized by low environmental impact, high purity of the recycled material, and low cost as compared to pyro- and hydrometallurgical methods. Full article

Developing an efficient recycling route for spent single-use medical devices is essential for recovering precious metals. The proposed complete hydrometallurgical route goes through the initial pyrolysis and acid digestion steps, expanding upon our previous relevant work in the field, followed by solvent extraction, stripping, and precipitation procedures. In this study, a complete hydrometallurgical process was developed for the recovery of gold, platinum, iridium, and tantalum, separating them from other metals, i.e., from iron, chromium, and nickel, also present in the examined medical devices, i.e., (i) diagnostic electrophysiology catheters, containing gold, (ii) diagnostic guide wires, containing platinum and iridium alloys, and (iii) self-expanding stents, containing tantalum. This study reports the experimental results of selecting an efficient extractant, stripping, and precipitation agent, along with the effects of key factors that influence each consecutive step of the process, i.e., agent concentration, aqueous to organic phase ratio, contact time, and pH, using simulated metal solutions and also applying the obtained optimal conditions to the treatment of real sample solutions. For the selective separation of gold, Aliquat 336 was used to extract it in the organic phase; it was then stripped using a thiourea solution and precipitated by utilizing an iron sulfate (II) solution and proper pH adjustment. The selective separation of platinum was achieved by using Aliquat 336 for the organic phase extraction and a perchlorate acid solution for stripping it back into the aqueous solution and adding a sodium bromate solution to precipitate it. Due to the similar chemical behavior, the selective recovery of iridium followed the same processes as that of platinum, and the separation between them was achieved through selective precipitation, as heating the solution and adjusting the pH value resulted in the selective precipitation of iridium. Lastly, the selective recovery of tantalum consists of extraction by using Alamine 336, then stripping it back to the aqueous phase by using sodium chloride, and precipitation by using potassium salt solution and proper pH adjustment. A total recovery of 88% for Au, 86% for Pt, 84% for Ir, and 80% for Ta was obtained, thus achieving a high uptake of precious metals from the examined real spent/waste samples. Full article

Subsurface structural distribution can be detected using Ground-Penetrating Radar (GPR). The distribution can be considered as road fingerprints for vehicle positioning. Similar to the principle of visual image matching for localization, the position coordinates of the vehicle can be calculated by matching real-time GPR images with pre-constructed reference GPR images. However, GPR images, due to their low resolution, cannot extract well-defined geometric features such as corners and lines. Thus, traditional visual image processing algorithms perform inadequately when applied to GPR image matching. To address this issue, this paper innovatively proposes a GPR image matching and localization method based on a novel feature descriptor, termed as central dense structure context (CDSC) features. The algorithm utilizes the strip-like elements in GPR images to improve the accuracy of GPR image matching. First, a CDSC feature descriptor is designed. By applying threshold segmentation and extremum point extraction to the GPR image, stratified strip-like elements and pseudo-corner points are obtained. The pseudo-corner points are treated as the centers, and the surrounding strip-like elements are described in context to form the GPR feature descriptors. Then, based on the feature description method, feature descriptors for both the real-time image and the reference image are calculated separately. By searching for the nearest matching point pairs and removing erroneous pairs, GPR image matching and localization are achieved. The proposed algorithm was evaluated on datasets collected from urban roads and railway tracks, achieving localization errors of 0.06 m (RMSE) and 1.22 m (RMSE), respectively. Compared to the traditional Speeded Up Robust Features (SURF) visual image matching algorithm, localization errors were reduced by 86.6% and 95.7% in urban road and railway track scenarios, respectively. Full article

The cobalt-containing products of an enterprise were selected as the object of this study. The separation effect of Cyanex 272 on Zn and Co was studied through a pilot test. The results showed that Cyanex 272 had a high extraction rate for Zn at pH 3–3.4, up to 99.8%. The extracted Zn²⁺ was enriched in the organic phase, and the Zn²⁺ in the organic phase was extracted back into the aqueous phase in the stripping stage by adding strong acid. Addition amounts of strong acid of 50 g·L⁻¹, 80 g·L⁻¹, and 100 g·L⁻¹ were set. The results showed that the addition amounts of 80 g·L⁻¹ and 100 g·L⁻¹ could significantly reduce the pH of the back-extraction solution and effectively enrich Zn²⁺ in the solution. There was a large amount of Zn²⁺ in the back-extraction solution, which could be used twice to prepare zinc carbonate products through neutralization and precipitation. By comparing the extraction effect, economic cost, and resource loss under different strong acid addition amounts, it was found that the 80 g·L⁻¹ strong acid addition amount was more suitable for the actual production process. This study provides data support and practical evidence for the selection of industrial extraction process parameters for Zn²⁺ separation in actual cobalt products. Full article

Wind turbine blades (WTBs) are prone to damage from their working environment, including surface peeling and cracks. Early and effective detection of surface defects on WTBs can avoid complex and costly repairs and serious safety hazards. Traditional object detection methods have disadvantages of insufficient detection capabilities, extended model inference times, low recognition accuracy for small objects, and elongated strip defects within WTB datasets. In light of these challenges, a novel model named DCW-YOLO for surface damage detection of WTBs is proposed in this research, which leverages image data collected by unmanned aerial vehicles (UAVs) and the YOLOv8 algorithm for image analysis. Firstly, Dynamic Separable Convolution (DSConv) is introduced into the C2f module of YOLOv8, allowing the model to more effectively focus on the geometric structural details associated with damage on WTBs. Secondly, the upsampling method is replaced with the content-aware reassembly of features (CARAFE), which significantly minimizes the degradation of image characteristics throughout the upsampling process and boosts the network’s ability to extract features. Finally, the loss function is substituted with the WIoU (Wise-IoU) strategy. This strategy allows for a more accurate regression of the target bounding boxes and helps to improve the reliability in the localization of WTBs damages, especially for low-quality examples. This model demonstrates a notable superiority in surface damage detection of WTBs compared to the original YOLOv8n and has achieved a substantial improvement in the mAP@0.5 metric, rising from 91.4% to 93.8%. Furthermore, in the more rigorous mAP@0.5–0.95 metric, it has also seen an increase from 68.9% to 71.2%. Full article

In the PUREX (the plutonium uranium reduction extraction) process, a plutonium barrier unit (1BXX) is used to achieve deep plutonium stripping. According to the operating experience of the French reprocessing plant, after the separation of uranium and plutonium in the first cycle (1B + 1BXX), the plutonium barrier unit has excellent stripping effect, such that the removal of plutonium from uranium can already be achieved in the first cycle, and the second cycle only needs to focus on the removal of neptunium from uranium in order to obtain a qualified uranium product. In recent decades, China has also been actively conducting research on the plutonium barrier unit process to reduce the plutonium concentration in the primary uranium product in the first cycle to avoid the need to remove neptunium and plutonium at the same time in the second cycle, and to improve the efficiency and feasibility of reprocessing. Due to the lack of design basis for plutonium barriers to achieve deep plutonium stripping at present, this study conducts a basic study on the plutonium barrier unit, aiming to provide data for the optimization of plutonium barriers in the actual reprocessing process at a later date. In this work, a kinetic study on the reduction and stripping of trace plutonium from dibutyl phosphate-containing organic phases was carried out first, and the kinetic equations for the reduction and stripping of Pu(IV) by U(IV) under flow process conditions were obtained. The effects of U(IV) addition on the extraction loss of U(IV) and the concentration distribution of U(IV) at various stages were investigated by process simulation. Additionally, the oxidation of U(IV) under process conditions was investigated to clarify the process chemistry of U(IV) oxidation and to provide a reference for the oxidation consumption of U(IV). Finally, the process parameters of the plutonium barrier unit were preliminarily designed based on the above research. Full article

Sustainability faces many challenges, including the availability of materials necessary for technological advancement. Rare earth elements (REEs), for example, are key materials for several manufacturing industries that can unlock renewable energy and sustainable development. In this study, a decanter centrifuge has been employed to successfully separated phosphoric acid and REE-containing particles from phosphoric acid sludge with concentrations ranging from 1000 to 2200 ppm REEs. Operating efficiently with up to 35 wt.% solids, the centrifuge was demonstrated to achieve approximately 95% phosphoric acid recovery and 90% REE recovery in a single pass, eliminating the need for additional processing steps. This breakthrough supports a proposed rare earth oxide (REO) recovery process integrating phosphoric acid (PA), elemental phosphorus (P4), and REO into two potential pathways: PA-REO and PA-P4-REO. These processes aim to reintroduce recovered phosphoric acid into the main product to significantly increase output and revenue. Post-separation, phosphorus-rich particles can be converted to P4, while REE-containing solids undergo further treatment including acid leaching, extraction/stripping, precipitation, and calcination to produce a marketable REO material. Technoeconomic analysis indicates promising profitability, with the PA-REO process showing a delta net present value (∆NPV) of USD 441.8 million over a 12-year period and expected return within a year of construction, while the PA-P4-REO process yields a ∆NPV of USD 178.7 million over a 12-year return period. Both pathways offer robust financial prospects and demonstrate the feasibility of commercial-scale REO recovery from phosphoric acid sludge, offering an economically feasible approach to produce REEs for future sustainable development challenges related to sustainability. Full article

The recovery of sulfuric acid in the presence of Zr(IV) and Hf(IV) was studied via solvent extraction using TEHA (tri-2-ethylhexyl amine) and its mixtures. A solidification phenomenon occurred in the loaded organic phase when a single TEHA was employed in the extraction of 1 to 5 M H₂SO₄. Octanol, decanol and TBP (tri butyl phosphate) were mixed with TEHA, separately, to prevent the solidification of sulfuric-acid-loaded organic. Due to the relatively high aqueous solubility of octanol and decanol, the mixture of TEHA + TBP was selected as the optimal system for the extraction of H₂SO₄. Simulated counter-current extraction and stripping experiments were performed on the basis of the McCabe–Thiele diagrams, indicating that sulfuric acid could be reduced by TEHA + TBP from 4.2 to around 0.5 M without Zr(IV) and Hf(IV) extraction and recovered by its complete stripping with water. The proposed sulfuric acid recovery step would contribute to the completion of the closed-circuit of the Zr(IV) and Hf(IV) separation process in our previous work and help to re-separate the remaining Zr(IV) and Hf(IV) in the sulfuric acid stripping solution. Full article

In order to overcome the interface emulsification problem of TBP-FeCl₃ systems and the instability of β-diketone systems in high-concentration alkaline medium, it is necessary to design and synthesize some new extractants. By introducing amino groups into a phosphorus extractant, a new 2-ethylhexyl hydrogen {[bis(2-ethylhexyl)amino]methyl} phosphonate acid (HA) extractant was synthesized. In this study, an efficient method of recovering lithium from the effluent of spent lithium-ion batteries (LIBs) is proposed. Experiments were conducted to assess the influential factors in lithium recovery, including the solution pH, saponification degree, extractant concentration, and phase ratio. Over 95% of lithium in the effluent was extracted into the organic phase, and nearly all lithium in the organic phase could be stripped into the aqueous phase using a 3 mol/L HCl solution. There was no significant decrease in extraction capacity after 10 cycles. The experimental results indicated that the extraction mechanism was a cation exchange process, and the extractive complex was proposed as LiA. Importantly, after three months of stable operation, the process demonstrated excellent stability and extraction efficiency, with rapid phase separation and a clear interface. This study offers an efficient, cost-effective, and environmentally friendly method for lithium extraction from the effluent of spent LIBs. Full article