Tungsten, a critical metal essential for high-performance and emerging technologies, is traditionally extracted from scheelite through energy-intensive, high-temperature, and high-pressure processes. This study presents an environmentally benign hydrometallurgical route for tungsten recovery from complex Hutti gold mine tailings using a dual organic leaching approach. Organic acids such as oxalic and citric acids were evaluated individually and in sequence to understand their leaching behavior and metal selectivity. The study briefly examines the leaching dynamics using oxalic acid and forms a base approach emphasizing the potential of employing a dual leaching aspect. Citric acid selectively dissolved impurity metals such as Fe, Ca, Mg, and Mn through complexation, while oxalic acid promoted tungsten dissolution via formation of soluble tungstate-oxalate species. The dual leaching approach affirms successful tungsten recovery (78.4%) with limited co-dissolution of impurities (6.8% Fe, 0.5% Ca, 10.8% Mg, and 8.9% Mn) using 0.5 and 0.25 mol/L concentrations of citric acid and oxalic acid, respectively. The enhanced recovery is attributed to the preferential dissolution of the target metal in organic acids owing to their chelation ability, resulting in the formation of stable metal-ligand complexes. The dual leaching aspect of the study was further validated through XRD analysis, peak intensity ratio determination, and quantitative analysis. Overall, the dual-organic-acid strategy provides a mild, selective, and sustainable alternative to conventional mineral-acid leaching, advancing green extraction practices for tungsten recovery from low-grade secondary resources.

This study presents an environmentally sustainable approach for recovering rare earth elements (REEs) from NdFeB permanent magnet waste using eco-friendly organic acids as alternatives to conventional mineral acids. The NdFeB magnet sample was leached with different organic acids, such as acetic, ascorbic, citric, malic, lactic, and tartaric acids; among them, ascorbic acid exhibits the highest selectivity toward REEs over iron. Under the optimized conditions: 0.5 mol/L ascorbic acid, 6 h leaching time, 10 g/L solid-to-liquid ratio, 600 r/min agitation speed, and 30 °C temperature, complete dissolution of REEs is achieved through a two-stage leaching process, while iron dissolution is limited to 17.7%. Kinetic analysis indicates that the leaching of REEs and Fe follows the diffusion-controlled mechanism. Following leaching, solvent extraction was employed for the selective removal of REEs from the leach solution using various organophosphorus extractants, including PC 88A, Cyanex 572, and Cyanex 272. Among the tested extractants, PC 88A shows the highest extraction efficiency. The McCabe-Thiele plot indicates that neodymium is efficiently recovered in two extraction stages with organic to aqueous phase ratio of 1:1. Counter-current test confirms this, leaving only 16.7 mg/L of Nd in the raffinate. REEs were subsequently stripped from the metal-loaded organic phase using 0.5 mol/L oxalic acid, resulting in 99.8% precipitation of REEs as their oxalate. The oxalate precipitates were thermally treated to obtain high-purity mixed rare earth oxides, confirming the effectiveness of the integrated leaching, extraction, and recovery approach for sustainable REE recycling from NdFeB magnet waste.

The increasing demand for rare earth elements (REEs) in advanced technological applications, combined with the limited availability of primary resources, has intensified efforts to recover REEs from secondary sources. Spent NdFeB magnets, commonly found in hard disk drives (HDDs), represent a rich and promising source, containing approximately 30% of REEs. This study focuses on the comparative leaching studies between roasted and unroasted NdFeB magnet samples using HCl as lixiviant. Leaching experiments were systematically conducted to evaluate the influence of key process parameters: acid concentration, temperature, and leaching duration on the recovery of valuable metals. The unroasted sample achieved 99.9% REEs recovery; however, high iron dissolution indicated poor selectivity. In comparison, the roasted sample demonstrated higher selectivity, with recoveries of 96.9% for Dy, 95.4% for Pr, and 93.2% for Nd, while iron dissolution was limited. Leaching kinetic analysis of roasted magnet powder indicated that rare earth leaching kinetics followed a mixed control mechanism, with the activation energy calculated as 39.35 kJ/mol within the temperature range of 30-60 degrees C.

The widespread use of neodymium-iron-boron (NdFeB) magnets has raised concerns about the environmental impact of their disposal, prompting the need for sustainable recycling strategies. Traditional solvents used in recycling are toxic and flammable, making them risky to use. Ionic liquids are safer and greener options with low vapor pressure, high stability, and less flammability. This study introduces an eco-friendly recycling approach utilizing the [P66614][Cy272] ionic liquid to selectively extract iron and recover rare earth elements (REEs) from the leach liquor of waste NdFeB magnets. Pre-treatment processes enhanced metal concentration before leaching, including demagnetization, grinding, and screening. Optimal leaching conditions: 2 mol L-1 HCl, 80 degrees C, 10 g L-1 pulp density, and 90 minutes, resulted in complete leaching of REEs (Dy, Pr, Nd), iron, and boron. Using 0.01 mol L-1 [P66614][Cy272] ionic liquid, 100% of the iron was removed from the leach liquor with minimal co-extraction of REEs (similar to 4%). Precipitation of iron leading to Fe2O3 (hematite) after calcination and is verified through XRD and SEM-EDS analyses. The ionic liquid also enabled 81.1% recovery of HCl from the leach liquor, reducing neutralization needs and operational costs. Subsequent REEs separation using 0.01 mol L-1 [P66614][Cy272] ionic liquid demonstrated high selectivity, achieving separation factors of 18.55 (Dy/Pr) and 15.52 (Dy/Nd) at pH 2.03. Dy(iii) was successfully separated from NdFeB leach solutions using counter-current extraction, leaving 6.0 mg L-1 in the raffinate, requiring two extraction stages at a 2 : 3 organic-to-aqueous phase (O/A) ratio. The reusability of the ionic liquid further enabled a sustainable, closed-loop recycling process. This approach highlights the potential for integrating ionic liquids into green technologies for NdFeB magnet recycling, ensuring resource recovery while minimizing environmental impact.

The SmCo5 magnet alloy is a powerful magnet used in defence, aerospace, and automotive transmissions. While shaping to form different magnets, a lot of scraps are produced. These wastes offer a sustainable way to recover the critical metals, Sm and Co, reducing reliance on primary raw materials. This study investigates the recovery of Sm and Co from SmCo5 magnet alloy scrap using solvometallurgical techniques, which utilise organic solvents for metal extraction while minimising water usage compared to traditional methods. Various organophosphorus extractants were tested as lixiviant, with the solvoleaching efficiency order D2EHPA > PC 88 A > Cyanex 572 > Cyanex 272, reflecting their decreasing acidity and influence on metal dissolution. The optimal solvoleaching conditions: 2 mol/L D2EHPA concentration, 80 degrees C temperature, 8 h leaching time, 400 rpm agitation speed, and 10 g/L pulp density resulted in near-complete recovery of samarium and cobalt. Samarium and cobalt were effectively separated from strip leach liquor using the sodium sulfate double salt precipitation method. Samarium was recovered as NaSm(SO4)(2)nH(2)O with a precipitation efficiency of 99.9 % under optimised conditions: 80 degrees C temperature, 90 min reaction time, Na2SO4:Sm molar ratio of 4:1, and pH 1.25. Cobalt in the residual solution was precipitated as cobalt oxalate with an efficiency of 99.7 % at 60 degrees C temperature, 60 min reaction time, and 1.25:1 oxalate to cobalt molar ratio. The precipitated cobalt oxalate was calcined at 450 degrees C, forming cobalt oxide (Co3O4). This study demonstrates solvometallurgical method as high-yield, sustainable solution for efficient SmCo5 magnet recycling with minimal environmental impact.

A novel approach for complexing lithium with lactic acid to enhance extraction efficiency and its application to spent LIBs was proposed in this study. Key parameters influencing the extraction were systematically examined, including lactic acid concentration, pH of the aqueous phase, concentration of extractant, diluent selection, phase ratio between organic and aqueous phase, and stripping efficiency. Lithium extraction showed a remarkable improvement, rising from 16% to 43%, as the lactic acid concentration enhanced from 0.01 mol∙L‒1 to 1.0 mol∙L‒1. This was achieved using D2EHPA (0.1 mol∙L‒1) at a maintained pH of 6.5. Maximum lithium extraction of 84.5% was observed at an O/A ratio of 5:1. Kerosene was a suitable diluent found from the different diluents employed for extraction. The 0.1 mol∙L‒1 D2EHPA exhibited a lithium loading capacity of 0.084 g∙L‒1. This optimized process was further extended to recover Li from waste LIB. 99.9% of Co and 91.2% of Li were extracted in three stages of cross-current extraction. Na2CO3 was utilized as a stripping agent for separating Co and Li. Using 2.5 mol∙L‒1 Na2CO3, almost 90% of the Li was precipitated as Li2CO3, and 99.8% of the Co was recovered.

The economic sustainability of battery materials relies on innovative extractive strategies. Hence, the current study proposes a combined approach of reduction roasting and solvoleaching with a phosphoric acid-based extractant for recovering lithium and cobalt from spent lithium cobalt oxide (LiCoO2) cathodes. The predissolution step involves reduction roasting at 300 °C using hydrogen peroxide to facilitate effective structural collapse and enhancing the metal dissolution efficiency. Subsequent nonaqueous leaching, or solvoleaching, achieves the dissolution of 83.2% cobalt and 91.8% lithium using 2.5 mol/L di-(2-ethylhexyl) phosphoric acid (D2EHPA) under optimized conditions (5 g/L pulp density, 600 rpm, 90 °C). Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) confirm the removal of target metals, while UV-vis spectroscopy and FTIR analysis reveal the complexation of Co-(II) as a tetrahedral coordination species, validating the reduction of Co-(III) to Co-(II) as a key dissolution mechanism. The study details the solvoleaching mechanism and emphasizes adapting a hydrometallurgical route to separate metal species completely. Metal stripping with H2SO4 achieves 99.4% Co and 99.8% Li recovery. Furthermore, the selective precipitation of Co2+ using oxalic acid was optimized through speciation modeling, ensuring a well-defined separation of cobalt and lithium at pH 2.5. Recyclability tests over five consecutive cycles confirm the efficiency of the solvent and support the integration of leaching and solvent extraction into a single, water-efficient recycling flowsheet. This approach provides a sustainable alternative to conventional aqueous-based methods. The findings demonstrate the viability of solvometallurgy for high-efficiency LIB recycling and suggest its broader potential for recovering strategic metals from secondary resources.

This study explores the extraction of Nd(III) from synthetic solutions using the ionic liquid [P66614] [Cy272]. Key extraction parameters, including the effect of phase contact time, initial pH, salting-out agents, extractant concentration, and temperature, were systematically optimized. Results revealed that a phase contact time of 15 min, an initial pH of 2.14, and 0.2 mol center dot L-1 NaCl as a salting-out agent and extractant concentration of 0.015 mol center dot L-1 [P66614][Cy272], achieved maximum extraction efficiency of 99.7%. Thermodynamic analysis confirmed the process is to be exothermic, spontaneous, and entropydriven, highlighting the strong complexation between Nd(III) and the ionic liquid [P66614][Cy272]. Stripping tests revealed that using 0.1 mol center dot L-1 H2SO4, achieved complete recovery (100%) of Nd(III) from the loaded-organic phase. These findings underscore the potential of [P66614][Cy272] ionic liquid as a green, efficient alternative to conventional extractants, providing high efficiency and reduced environmental impact. This research advances hydrometallurgical recycling of REEs, particularly from end-of-life NdFeB magnets, supporting sustainable resource recovery and addressing global supply challenges for critical materials.

The presence of critical metals like lithium, manganese and cobalt is crucial in recycling spent lithium-ion batteries (SLIB). This study focuses on recovering these metals from SLIB powder through leaching, precipitation and solvent extraction. Key parameters affecting process efficiency were evaluated, along with the mechanism and kinetics of metal recovery. Optimal leaching rates of 96.8% lithium, 99.1% manganese, and 97.9% cobalt were achieved using 27% (v/v) HCl at 70 degrees C and 10% (w/v) pulp density over 2 hours. Manganese was selectively precipitated with sodium persulphate at pH 1.3 for 4 hours. Lithium and cobalt were separated from the Mn-free solution using Na-Cyanex 272 at equilibrium pH 5.5, yielding a cobalt separation factor of 80.5. The McCabe-Thiele plot indicated two extraction stages with an aqueous-to-organic ratio of 1:1, achieving 99.6% cobalt extraction and 8% lithium co-extraction. Cobalt was back-extracted with 6% (v/v) HCl. The proposed process flow sheet offers a simple, effective method for metal recovery, supporting recycling businesses in extracting valuable resources efficiently. La pr & eacute;sence de m & eacute;taux critiques, dont le lithium, le mangan & egrave;se et le cobalt, joue un r & ocirc;le critique dans le proc & eacute;d & eacute; de recyclage des batteries lithium-ion usag & eacute;es (SLIB). Ce travail se concentre sur la r & eacute;cup & eacute;ration des m & eacute;taux d'une poudre r & eacute;cup & eacute;r & eacute;e & agrave; partir de SLIB mixtes par lixiviation, pr & eacute;cipitation et extraction par solvant. On a & eacute;tudi & eacute; l'impact de divers param & egrave;tres sur l'efficacit & eacute; de la lixiviation, de la pr & eacute;cipitation et de l'extraction par solvant. De plus, on a explor & eacute; le m & eacute;canisme et la cin & eacute;tique du Li, du Mn et du Co. Les r & eacute;sultats exp & eacute;rimentaux montrent que l'on pourrait lixivier & agrave; des taux de lixiviation sup & eacute;rieurs de 96.8% de lithium, 99.1% de mangan & egrave;se et 97.9% de cobalt en utilisant 27% (v/v) de HCl & agrave; une temp & eacute;rature de 70 degrees C et une densit & eacute; de pulpe de 10% (p/v) en 2 heures. Le mangan & egrave;se & eacute;tait pr & eacute;cipit & eacute; s & eacute;lectivement de la solution de lixiviation en utilisant du persulfate de sodium comme oxydant au pH de 1.3 pendant 4 heures. Par la suite, on a extrait la liqueur de lixiviation sans Mn, avec du Cyanex-Na 272 pour & eacute;liminer s & eacute;lectivement le lithium et le cobalt. On a observ & eacute; le facteur de s & eacute;paration le plus & eacute;lev & eacute; de 80.5 & agrave; un pH d'& eacute;quilibre de 5.5. La courbe de McCabe-Thiele a projet & eacute; le besoin de deux & eacute;tapes avec un rapport aqueux:organique de 1:1 pour extraire 99.6% du cobalt, avec une coextraction de 8% du lithium. On a utilis & eacute; 6% (v/v) de HCl pour la r & eacute;tro-extraction du cobalt de la solution organique charg & eacute;e. Pour les entreprises de recyclages, le sch & eacute;ma propos & eacute; pour la lixiviation et la s & eacute;paration de chaque m & eacute;tal cl & eacute; est un proc & eacute;d & eacute; simple mais efficace.

Recycling spent Li-ion batteries (LIBs) is paramount to pursuing resource efficiency and environmental sustainability. This study introduces a synergistic approach for selectively leaching and separating strategic metals from waste LIBs, representing a more efficient alternative to traditional single-acid-based leaching methods. The research also thoroughly analyzes diverse extraction parameters, aiming to achieve clean metal separation through synergistic concepts rather than single-phase extraction. The outcome of this study is developing a comprehensive downstream process, advancing the cause of sustainable waste management in the LIB industry. Under specific conditions with 0.6 mol/L total acid content (0.5 mol/L tartaric acid + 0.1 mol/L ascorbic acid), 99.9% cobalt and 100% lithium were effectively leached. The subsequent extraction process achieved a clean separation, with 48.3% of cobalt extracted using a mixture of 0.1 mol/L Alamine-336-Cyanex-272 (A-336-Cy-272) from the leach liquor with no coextraction of lithium, and this efficiency was improved to 67.3% by adjusting the pH from 2.44 to 7.5. However, it is worth noting that increasing the extractant concentration led to an antagonistic effect. To further enhance cobalt enrichment in the organic phase, the McCabe-Thiele plot method was recommended, employing saponified Cy-272. Moreover, the regeneration of saponified Cy-272 was investigated, and the stripped solution was processed with NaOH to form Co(OH)2, subsequently converting it into cobalt oxide (Co3O4) through calcination.

This piece of work aims to study the extraction behavior of light and heavy rare earth elements, which are often found in permanent magnets, using a mixture of tri-octyl amine and bis-(2,4,4-trimethylpentyl) phosphinic acid from a chloride medium. The study showed that the extraction efficiency of Dy(III) is more than that of Nd(III) and Pr(III). Benzene proved to be an effective diluent. Increasing the pH of the aqueous phase improved the extraction percentages, with maximum extractions of 98.4% for Dy(III), 61.2% for Nd(III), and 58.3% for Pr(III) at pH 5.04 using 0.1 mol/L of each extractant. Adding sodium chloride enhanced the extraction efficiency due to the salting-out effect. The extraction mechanism has been proposed based on the slope analysis and FTIR data. From thermodynamic variables, the process was found to be exothermic. The simulated leach liquor of NdFeB magnets showed the highest separation factors of 67.7 (Dy/Pr) and 56.9 (Dy/Nd) at pH 2.05 with 0.25 mol/L extractants. The counter-current study showed that 4.15 mg/L Dy(III) was left behind in the raffinate indicating 97.4% removal of Dy(III) in two stages at unity phase ratio. Testing with actual leach liquor from hard disk magnets revealed a preference for iron extraction, which impeded REE extraction.

It is essential to develop a leaching procedure that uses minimal acid consumption, is economical, recovers large amounts of metal, and has a minimal negative impact on the environment. In this paper, a viable hydrometallurgical method using acetic acid as a leachant is suggested for recovering critical metals from waste LCO-type batteries. Several leaching parameters were examined in order to optimize the leaching conditions. With 1.2 mol/L acetic acid, 7% H2O2, 90 °C, an S/L ratio of 10 g/L, and a 60 min leaching period, the maximum leaching efficiencies of Li (99.6%) and Co (95.6%) were attained. By investigating the different kinetic models, it was feasible to figure out the reaction’s pace, as well as the mechanism involved in the leaching process. It was found, through the comprehensive kinetic studies of the leaching process, that the surface chemical reaction controls the leaching mechanism for waste LCO-type batteries. The economic viability of the current leaching procedure in comparison to those of earlier approaches is also discussed.

The necessity to preserve the environment and accomplish the rising demand for precious metals has made recycling of spent lithium-ion batteries (LIBs) crucial for conducting business in a sustainable way. An eco-friendly leaching process using ascorbic acid has been suggested in this work to leach critical metals from the spent calcined LIB sample. The optimum leaching of Li (100

A synthesized ionic liquid reagent Cyphos-SCN (trihexyl(tetradecyl) phosphonium thiocyanate) was utilized for the recovery of cobalt and lithium from the leach liquor from end-of-life lithium-ion battery powder. Several leaching parameters were studied to find the optimum leaching condition. The maximum leaching efficiency of lithium (100

Cobalt is a key element of the lithium-ion batteries that supply energy and continuous power to several electronic equipments such as cellphones, computers, and electric vehicles. Due to the depletion of primary sources of metal extraction and limited supply, countries are now focusing on recycling secondary resources for economic and sustainable management. Though the majority of the technologies involved are focused on industrial-scale development, they lack eco-friendliness and efficiency. The dead lithium-ion batteries containing several valuable metals such as cobalt, lithium, manganese and nickel are regarded as an appealing secondary resource. Battery recycling is required not only to reduce energy consumption but also to alleviate the scarcity of rare resources and eliminate pollution from hazardous components, as the world moves toward more sustainable industries such as consumer electronics and electric vehicles. The significance of cobalt recovery from secondary resources is emphasized in this paper. From the research, it is found that the amount of cobalt is more in the spent LIBs. Hence, focus is given on the green method of leaching of the spent Lithium-ion batteries (LIB) and extracting the valuable metals such as cobalt, nickel and lithium using organic acids. The method of using organic acids as leachant is environmentally friendly, cost-effective, and has the potential to provide sustainable development in the battery industry. This initiative is aimed to stimulate people's interest in wasted LIBs recycling with organic acids and raise awareness of the benefits.

Recovering precious metal ions like Co, Li, Mn, and Ni from discarded lithium-ion batteries (LIBs) has significant environmental and economic benefits. Also, graphite will be in high demand in the coming years due to the development of LIBs for use in electric vehicles (EVs) and the need for it for electrodes in a variety of energy storage devices. However, it has been overlooked during the recycling of used LIBs, which resulted in resource waste and environmental pollution. In this work, a comprehensive and environmentally friendly approach for recycling critical metals as well as graphitic carbon from discarded LIBs was proposed. To optimize the leaching process, various leaching parameters were investigated by employing hexuronic acid or ascorbic acid. The feed sample was analyzed using XRD, SEM-EDS, and a Laser Scattering Particle Size Distribution Analyzer to determine the phases, morphology, and particle size. 100% of Li and 99.5% of Co were leached at the optimum conditions of 0.8 mol L-1 ascorbic acid, a particle size of -25 μm, 70 °C, 60 min of leaching time, and 50 g L-1 of S/L ratio. A detailed study of the leaching kinetics was carried out. The leaching process was found to be well-fitted with the surface chemical reaction model based on the findings of temperature, acid concentration, and particle size variations. To obtain pure graphitic carbon after the initial leaching, the leached residue was subjected to further leaching with various acids (HCl, H2SO4, and HNO3). The Raman spectra, XRD, TGA, and SEM-EDS analysis of the leached residues following the two-step leaching process were examined to exemplify the quality of the graphitic carbon.

This research explored the significance of Cyphos IL 101 in recovering metal values from waste LiMn 2 O 4 batteries. Several leaching parameters were investigated to recover metals from the leach liquor of the battery material. The maximum leaching efficiency of Li (100%) and Mn (99.6%) was attained with 3.0 mol/L hydrochloric acid, 30°C, S/L ratio of 10 g/L, and 60 min leaching duration. The leaching process was diffusion-controlled. At pH 5.5, the separation of manganese and lithium exhibited excellent selectivity towards manganese over lithium using 0.1 mol/L Cyphos IL 101. 99.6% manganese extraction and negligible lithium extraction were obtained with two stages of counter-current extraction at A/O 1:1 predicted by the McCabe-Thiele plot. Using 0.1 mol/L hydrochloric acid, a stripping efficiency of 99.4% was attained for manganese.