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A review of technologies for the recovery of metals from spent alkaline and zinc–carbon batteries
Abstract
The main aim of this paper is to review and evaluate the recovery studies and associated technologies for metals from spent batteries. More attention was given especially to the recovery of Zn and Mn from spent alkaline and zinc–carbon batteries. Nowadays much research work is concentrated on the recovery of Zn and Mn from alkaline and zinc–carbon batteries. Various different metal recovery processes including physical, pyrometallurgical and hydrometallurgical ones are discussed. Compared to pyrometallurgical methods, hydrometallurgical methods are becoming a well-established and efficient method for recovering metals from raw materials. Although there have been many proposed or currently applied recovery processes majority of them are effective only in recovering certain components of spent batteries. Considering the more stringent regulations and cost, environmental protection, preservation of raw materials issues; thus, effective, economical and practical recovery technologies are required not only for metal recoveries but also for other components of batteries such as plastic, paper, steel, etc. More research work should be conducted to develop such recovery technologies. In addition, process control and plant optimization studies should also be conducted for more feasible full-scale applications.
... Alkaline batteries are one of the most widely used primary batteries, containing manganese dioxide as the cathode, zinc powder as the anode, and an alkaline potassium hydroxide electrolyte [1,18,21,22]. They offer high energy density, stable voltage output, long shelf life (5-7 years), and tolerance to high-drain devices. ...
... • Zinc-carbon batteries, also known as carbon-zinc or dry cell batteries. They contain a zinc anode, a carbon cathode, and an electrolyte gel [1,2,22]. Zinc-carbon batteries are inexpensive, deliver 1.5 V voltage, and have a shelf life of 5 years [1,22]. ...
... They contain a zinc anode, a carbon cathode, and an electrolyte gel [1,2,22]. Zinc-carbon batteries are inexpensive, deliver 1.5 V voltage, and have a shelf life of 5 years [1,22]. Their low energy density makes them suitable for low-power devices, like remote controls, toys, radios, and smoke detectors [1,2]. ...
As the demand for batteries continues to surge in various industries, effective recycling of used batteries has become crucial to mitigate environmental hazards and promote a sustainable future. This review article provides an overview of current technologies available for battery recycling, highlighting their strengths and limitations. Additionally, it explores the current challenges faced by the industry and discusses potential future advancements. Through an in-depth analysis of the state-of-the-art recycling methods, this review aims to shed light on the progress made in battery recycling and the path ahead for sustainable and efficient battery waste management.
... Las baterías alcalinas agotadas representan una importante fuente de recursos de metales tales como el zinc, manganeso y plomo [2,6], los cuales pueden encontrarse con niveles de alta concentración y en algunos casos con una concentración más grande que los recursos minerales [8]. Es conocido que las reservas de zinc estarán agotadas dentro de 20-40 años [2], por lo tanto, la recuperación de metales a partir de baterías agotadas resulta ser económicamente conveniente debido a que grandes cantidades de residuos sólidos pueden ser una fuente de materia prima secundaria, como por ejemplo para el manganeso [4,6,[9][10][11]. ...
... Por otro lado, el objetivo de la conminución es el de disminuir el tamaño de partícula con la finalidad de liberar los diferentes tipos de materiales a ser recuperados. En el segundo paso del procesamiento metalúrgico básicamente se tiene tres diferentes vías: hidrometalúrgica, pirometalúrgica o un proceso híbrido, es decir se emplean procesos hidrometalúrgicos y/o pirometalúrgicos para obtener metales o compuestos metálicos [6,8,11]. ...
... Finalmente, las especies metálicas son recuperadas a partir de soluciones puras de metales u óxidos metálicos, hidróxidos o sales. Los proseos hidrometalúrgicos más empleados en el reciclado de baterías son: el Proceso TNI trata baterías de NiCd; el proceso BATENUS trata diversos tipos de baterías; el proceso ZINCEX trata baterías con contenido de Zn; el proceso RECUPYL trata diversos tipos de baterías [6,11]. ...
En las pilas alcalinas de Zn/MnO2 , el dióxido de manganeso electrolítico (DME) se utiliza como cátodo y constituye una parte muy importante de los residuos domésticos que aportan metales pesados a los residuos sólidos urbanos. Este estudio describe la recuperación de DME por electro-oxidación en tela de carbón en licores ácidos lixiviados de baterías alcalinas usadas. Los rendimientos máximos de extracción para Mn y Zn fueron 43,68% (0,744 molL-1 ) y 56,11% (0,7321 molL-1 ) respectivamente. Los voltamogramas de un electrodo de carbón vítreo para la deposición de DME a partir de licores lixiviados se obtuvieron entre 0,0 y 1,4 V frente a ECS, y presentan un pico anódico a 1,2 V frente a ECS. Además, aparece un pico catódico a 0,97 V frente a ECS. La difracción de rayos X revela la presencia de nsutita (γ-MnO2) y manganita (γ-MnOOH) para todos los depósitos, y la morfología de los depósitos fue observada por microscopia electrónica de barrido (SEM).
... Zn-Mn batteries are not rechargeable and run out of power in a relatively short period. They contain Hg, Cu, Zn, and Mn (Calin et al. 2021), and the 12-28% Zn and 26-45% Mn increase their recycling potential (Sayilgan et al. 2009). ...
... Comminution and separation of steel and plastic are necessary to minimize impurities (Sayilgan et al. 2009). Sulfuric acid leaching can be used to dissolve Zn, Cu, Ni, Cd, and Hg, followed by solvent extraction for Zn recovery and selective ion exchange for other metals. ...
... In the noncontact mode with a dialysis membrane separation, 96% Zn was leached in 1 d with acid regardless of test culture. Mn II O dissolves at low pH, whereas dissolution of Mn III 2 O 3 and Mn III,IV 3 O 4 requires a reductant (Sayilgan et al. 2009). Up to 97% Mn was leached reductively with Fe 2+ as the reductant by the mixed culture in 13 d. ...
This review addresses the recovery of metals from all the main types of spent batteries (including Li-based, Zn-based, and Ni-based batteries) using bioleaching processes. Traditional processes are based on pyrometallurgical and hydrometallurgical methods and can be costly and, in some cases, cannot effectively recover the metals used in battery manufacture. Biobased hydrometallurgy may circumvent some of these drawbacks. This review presents a classification of batteries based on chemical composition from a recycling point of view. The bacterial and fungal leaching for each type of battery is reviewed. The research outputs are compared in each section, and chemical and biological mechanisms are presented. In addition, the catalytic effect of metals on the bioleaching process is reviewed for each battery. The results indicated that the main bioleaching mechanisms are the reactions of metals with metabolites, acid dissolution, and their combinations with oxidation-reduction reactions. The reactions presented in the literature are assessed and modified thermodynamically. The advantages and disadvantages of batteries bioleaching are discussed, and a future perspective is drawn. Although battery bioleaching has high efficiency and is an environmentally friendly method, with no gas emission and low energy consumption, slow kinetics and low pulp densities are among the major limiting factors hindering bioprocessing development from pilot to commercial scale.
... The presence of valuable yet hazardous species in batteries necessitates their appropriate recycling. According to 91/157/EEC legislation, batteries should be collected and treated to eliminate or reduce their toxic constituents [10,11]. An important pretreatment is the separation of the metallic parts in order to recover the corresponding valuable metals via hydrometallurgical or pyrometallurgical routes [10]. ...
... According to 91/157/EEC legislation, batteries should be collected and treated to eliminate or reduce their toxic constituents [10,11]. An important pretreatment is the separation of the metallic parts in order to recover the corresponding valuable metals via hydrometallurgical or pyrometallurgical routes [10]. Selective recovery of metals from household batteries are carried out using various commercial methods [10], e.g. ...
... An important pretreatment is the separation of the metallic parts in order to recover the corresponding valuable metals via hydrometallurgical or pyrometallurgical routes [10]. Selective recovery of metals from household batteries are carried out using various commercial methods [10], e.g. BATENUS [12], Recupyl [13], Varta 1 [14], TNO [15], Eco-bat Indiana [16], and Toxco [17]. ...
Due to the progressive shortage of primary resources and growing environmental concerns over industrial and household residues, proper management of electronic wastes is of great importance in addressing sustainability issues. Spent batteries are considered as important secondary sources of their constituting components. In this study, the co-recycling of used zinc-carbon and lithium-ion batteries was performed aiming at the recovery of their manganese and lithium contents as compounds which can be used as precursors for the synthesis of spinel LiMn2O4. Manganese was recovered in the form of amorphous, submicron, spherical nodules of MnO2 after acid leaching of zinc-carbon battery pastes. Lithium was obtained from nickel-manganese-cobalt (NMC) batteries as its monohydrate oxalate (C2HLiO4.H2O) through selective leaching in oxalic acid followed by crystallization. Lithium carbonate was also prepared by subsequent calcination of the oxalate. The synthesis of LiMn2O4 spinel cathode was investigated using the reclaimed Li- and Mn-containing compounds via solid-state synthesis method. The effect of such parameters as type of precursors (C2HLiO4.H2O/Li2CO3 with Mn2O3/MnO2), temperature (750, 800, and 850 °C), and time (8 and 10 h) on the synthesis of LiMn2O4 was investigated. The products were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The crystallographic parameters from XRD analysis were used to predict the electrochemical behavior of the synthesized cathode materials. Based on these, the spinel powder synthesized at 850°C−10h from Li2CO3−Mn2O3 starting mixture was determined as the cathode material with the best electrochemical properties among the synthesized samples. The galvanostatic charge/discharge evaluation within the voltage range of 2.5–4.3 V showed the specific capacity of the 850°C-10 h sample to be 127.87 mAhg−1.
... Several studies have been reported to recover Zn and Mn from the electrode powder of spent alkaline batteries. Sadeghi et al. [3] and Sayilgan et al. [4] have conducted reviews on this critical issue. Most of these studies adopted pyrometallurgical techniques such as volatilization [5] or roasting [6] at a high temperature, or hydrometallurgical techniques such as leaching with various reagents including sulfuric acid (H 2 SO 4 ) [7] and the addition of oxalic acid (H 2 C 2 O 4 ) or citric acid (C 6 H 8 O 7 ) as the reducing agent [8,9], sodium hydroxide (NaOH) [7,10], ammonium carbonate (NH 4 ) 2 CO 3 [7], and ammonium chloride (NH 4 Cl) [11], followed by precipitation [8], solvent extraction [12], or electrolysis [13]. ...
... MnF x can be used as a fluorination agent in thin-film production [18] or organic chemical syntheses [19], as well as in the fabrication of alloys [20], special glass, and lasers [21]. Moreover, MnO 2 is primarily used to produce electrolytic MnO 2 electrode powder for alkaline and zinc-carbon batteries, and to produce oxidants such as KMnO 4 . Carbon powder can be used as a raw material for activated carbon production. ...
In this paper, a novel procedure is proposed for comprehensively recovering zinc fluoride (ZnF2), manganese fluorides [MnFx(x = 2, 3)], manganese dioxide (MnO2), and carbon powder from the electrode powder of spent alkaline batteries. Firstly, hydrofluoric acid (HF) leaching is conducted on the electrode powder of spent alkaline batteries. Secondly, potassium permanganate (KMnO4) is introduced into the leachate to selectively precipitate manganese (Mn) ions to recover MnO2. Subsequently, the water content in the leachate is evaporated to recover ZnF2. Finally, the leaching residue is leached again by using HF, after which the water content in the leachate is evaporated to recover MnFx. The results indicated that under optimal conditions of a HF concentration of 4 M, a leaching time of 15 min, and a liquid–solid ratio of 5 mL/g, the optimal leaching selectivity for Zn and Mn was achieved and the leaching efficiencies of Zn and Mn were 97.83% and 39.94%, respectively. When KMnO4 with a dosage (KMnO4/Mn ion molar ratio) of 0.5:1 was added to the leachate, MnO2 with a grade of 91.68% and a Mn recovery of 39.07% was obtained. In addition, ZnF2 with a grade of 97.98% and a Zn recovery of 96.15% was also obtained after removing the water content from the leachate via evaporation. Under the optimal conditions of a HF concentration of 2 M, a leaching time of 15 min, and a liquid–solid ratio of 10 mL/g for the leaching residue, followed by removing the water content in the leachate via evaporation, MnFx with a grade of 94.20% and a Mn recovery of 59.46%, was obtained. The residue of the releaching process was carbon powder. The effectiveness of the proposed recovery procedure was confirmed.
... The increasing demands for metals, coupled with constraints raised by various legislations on environmental protection and resource management, have made it imperative to partly satisfy the need for such metals of concern from secondary sources such as spent dry cell batteries [9 -13]. Dry cell batteries are known to contain zinc, manganese, iron, nickel, and other heavy metals [14] hence the need for recycling and recovering valuable metals from these secondary resources. ...
... There have been proposition of various reductants such as organic acids [14] and sulphur dioxide [18] for the acid leaching of manganese from spent dry cells. ...
The recovery of manganese and zinc from spent zinc-carbon dry cells using sulphuric acid and glucose as the leaching medium and reducing agent respectively was studied to determine the optimum processing parameters for increasing the recovery of the manganese content. Leaching tests were done using the Response Surface Methodology with the process variables being leaching time, temperature, acid concentration and glucose dose. Regression equations were obtained from the experimental data for the extraction of manganese and zinc, and the main effects and interactions from the leaching studies were investigated by the analysis of variance (ANOVA). Experimental results indicate that the dissolution of the battery materials depends largely on the leaching temperature and glucose dose, with the optimum yield of manganese and zin-c being 81.93 and 98.43 %, respectively corresponding to a leaching temperature of 70oC, leaching time of 150 min, sulphuric acid concentration of 4 M and glucose dose of 0.5 g/L.
... Pyrometallurgical treatment of end-oflife Zn-C and alkaline batteries is usually performed at temperatures between 900-1500 °C and does not necessarily require the dismantling of the batteries. The processes are, however, energy-consuming and require the application of additional equipment in order to reduce the environmental loads [11]. Hydrometallurgical methods usually involve several steps, including pre-treatment, leaching and separation of metals. ...
... Those methods do not require the application of high temperatures, and no harmful substances are emitted into the air. The disadvantages are mainly the fact that the procedure requires multiple operations and the application of harsh chemicals and may lead to wastewater discharges [11]. A comprehensive approach to the recycling of end-of-life Zn-C and alkaline batteries was described by Tran et al. [12]. ...
The utilization of end-of-life batteries (including Zn-C and alkaline batteries) is one of the areas that need to be perfected in order to provide environmental and human safety as well as to contribute to closing the material loop, as described in the EU Green Deal. The presented study shows the environmental impacts of the two selected pyrometallurgical technologies (processing of the black mass from waste Zn-C and alkaline batteries as an additive to an existing process of the recycling of steelmaking dust and treatment of the black mass as the primary waste material, both processes performed in a Waelz kiln). The presented LCA-based study of the recycling of end-of-life Zn-C and alkaline batteries focused on terrestrial ecotoxicity can be a useful tool in the process of the development of a circular economy in Europe, as it provides a multi-disciplinary overview of the most important environmental loads associated with the described recycling technologies. Therefore, the goal of the presented study was to compare the environmental performance (utilizing LCA) of two different metallurgical processes of black mass utilization, i.e., the conventional method utilizing black mass as a co-substrate and the newly developed method utilizing black mass as a primary substrate.
... Since primary batteries, such as manganese and alkaline batteries, are versatile, convenient, inexpensive, and essential for electronic devices, their consumption has been steadily increasing [1]. In particular, manganese and alkaline batteries are mainly used in electronic devices requiring small power [2]. Also, they are consumed and discarded in a short time, resulting in a lot of their waste. ...
... Recently, the resourcization of SPBs has attracted increasing attention from an economic, environmental, and tech-nological perspective [7,8]. Meanwhile, various research had focused on the recovery of valuable metals, such as manganese, zinc, etc., from SPBs [2,9,10]. ...
This work synthesized spent primary batteries (SPBs)-based (SB) catalyst from the black mass (BM) of the respective SPBs of R and D companies and tested it in the complete oxidation of volatile organic compounds (VOCs) to examine its effectiveness. In particular, benzene, toluene, and o-xylene (BTX) were chosen as representative VOCs. In addition, the physicochemical properties of the RSB and DSB catalysts prepared from the BMs in the SPBs of R and D companies, respectively, were characterized by ICP/OES, SEM/EDX, BET, XRD, TGA, O2-TPO, H2-TPR, and XPS analyses. Notably, the manganese-rich DSB catalyst had a higher activity compared to the RSB catalyst. Also, the dominant crystal phases of the RSB catalyst were of C, ZnMn2O4, Mn3O4, ZnO, and C2K2, and those of the DSB catalyst were of C and MnO2. In particular, the manganese oxide species significantly influenced the catalytic activity. Furthermore, the lattice oxygen mobility of the catalyst contributed to the VOCs complete oxidation. In effect, the BTXs were completely oxidized at less than 380 and 360 ℃ over the RSB and DSB catalysts, respectively, at a gas hourly space velocity of 50,000 h⁻¹.
... By definition, a substance that participates in the reaction but not used up [1][2][3] and provides an alternative route with lower activation energy [4][5][6][7] is called catalyst. Industrial catalysts should be mechanically strong, selective, active, stable (to overheating), robust, easily be regenerated, and so forth [4][5][6][7]. ...
... [15] Disposal of these spent catalysts represent an increasing environmental problem due to their metallic content, being considered as hazardous waste [9-10]. Reusability and recycling of catalysts and catalytic materials ensures minimization of wastes, reduction in production costs, preservation of raw materials and environmental protection [3]. ...
Base metals Zn, Fe, Cr and Mg were recovered from used (catalytic cracking) catalyst using sulfuric acid leaching method. After pre-treatment at 400 o c for 4h, three sets of leaching fractions were carried out on the spent FCC catalyst. The residues were analyzed using FTIR and XRF techniques, while the leach liquors were analyzed using AAS technique to determine the concentrations of the leached metals present. Variable sulfuric acid concentrations of 0.5M, 1M and 2M; temperatures of 40, 60 and 80 o and resident time (1h, 1.5h and 2h) were used. Optimum recovery was observed at heating temperature of 80 o C, concentration of 2M and 2h leaching time.
... Several pyrometallurgical reduction procedures have been developed for recycling spent alkaline batteries. For instance, proprietary processes like Sumitomo, Batrec and Citron have been extensively documented in the literature (Espinosa and Mansur 2019;Sayilgan et al. 2009;Bernardes et al. 2004), along with various experimental systems (Belardi et al. 2012;Hu et al. 2021;Yeşiltepe et al. 2019). In general, the pyrometallurgical recycling of spent alkaline batteries involves two primary stages: a mechanical treatment, such as shredding, followed by a thermal process in a suitable reactor or furnace. ...
The recycling of heavy metals contained in alkaline batteries allows minimizing the environmental impact and gives an alternative use to this waste, which can be used in the pyrometallurgical industry. In the present research work, we evaluated the possibility of reducing the manganese oxide black mass from discarded alkaline batteries to produce metallic manganese, using charcoal as a reducing agent. The procedure begins with the characterization of the raw materials, the stoichiometric calculations and the preparation of a practical method to produce self-reducing pellets, composed of manganiferous material, charcoal and bentonite as agglomerant. Computer simulations were performed, to establish the appropriate thermodynamic conditions for reduction. The tests were carried out in a tubular-type furnace, and the results obtained were evaluated using optical microscopy, scanning electron microscopy coupled with microchemical analyses and X-ray diffraction techniques. It was verified that the agglomerates showed a self-reducing behavior, so an increase of the %Mn in the samples due to increasing the temperature of the reduction treatment was found, as well as the presence of a metallic manganese phase that was identified by X-ray diffraction analysis.
Graphical Abstract
Flow sheet for the production of self-reducing pellets containing eucalyptus charcoal for the recycling of manganese contained in spent alkaline batteries
... Other crucial factors studied consist of the type and concentration of the manganese precursor. In this report, cyclic voltammetry (CV) has been applied to study the effect of using CH 3 (COO) 2 Mn compared with MnSO 4 and the effect of acid addition [6,7]. Only a few studies have investigated zinc-manganese RFB system, thus far. ...
... [6] However, the cost, limited sources of raw materials, and environmental and safety issues of LIBs are nonnegligible in satisfying the ever-growing energy requirements related to regional and global carbon neutrality. [7][8][9][10] Hence, aqueous batteries, including lead-acid batteries, [11] Ni-Cd batteries, [12] and Zn-Mn alkali batteries, [13] are still occupying the great majority of the rechargeable batteries market because of their lower cost, abundant resources, and higher safety compared to organic-based batteries such as LIBs. [14,15] However, owing to the narrow electrochemical stability window (ESW), the much-lower energy density, self-discharge, and low charge-discharge efficiency make these old-fashioned aqueous batteries lose their competitiveness, especially in high-end electric devices. ...
Abstract Recently, aqueous rechargeable zinc batteries (ARZBs) have become a hot topic in secondary batteries. Constant attention has witnessed the development of ARZBs, such as active materials, reaction mechanisms, and mass transport, and huge successes have been achieved. However, as the fundamental basis of battery monitoring in real‐time and the theories of ARZBs, the in situ characterization techniques are equally worth discussing but the relevant review remains missing. Herein, this review focuses on the in situ characterization techniques of visualization and spectroscopy characterizations for ARZBs. Typical research of the in situ techniques is comprehensively discussed, including the setup of the in situ cells, the working principle of characterizations, the application, and the analysis applied in ARZBs. With the help of in situ characterizations, the reaction dynamics, transport kinetics, and thermodynamics in ARZBs can be thoroughly researched. Finally, the current primary challenges and future opportunities faced by in situ techniques toward ARZBs are also summarized.
... The Batrec process, which since the 1980s was focused on alkaline and Zn-C batteries, currently is used for LIBs recycling with an annual capacity of 200 T a year [71]. The battery cells initially stored and shredded in a CO 2 atmosphere are pretreated with moist air. ...
Due to the accumulation of waste mobile devices, the increasing production of electric vehicles, and the development of stationary energy storage systems, the recycling of end-of-life Li-ion batteries (EOL LIBs) has recently become an intensively emerging research field. The increasing number of LIBs produced accelerates the resources' depletion and provokes pollution. To prevent this, the global communities are concerned with expanding and improving the LIBs recycling industry, whose biggest problems are either large gaseous emissions and energy consumption or toxic reagents and low recycling yields. These issues are most likely solvable by upgrading or changing the core recycling technology, introducing effective benign chemicals, and reducing cathode losses. In this review, we analyze and discuss various LIB recycling approaches, emphasizing cathode processing. After a brief introduction (LIB's design, environmental impact, commercialized processes), we discuss the technological aspects of LIB's pretreatment, sorting and dissolving of the cathode, separation of leached elements, and obtaining high-purity materials. Covering the whole LIB recycling line, we analyze the proven and emerging approaches and compare pyrometallurgy, hydrometallurgy, and cathode's direct restoration methods. We believe that the comprehensive insight into the LIB recycling technologies made here will accelerate their further development and implementation in the large-scale battery industry.
... United States Environmental Protection Agency (USEPA) reported that about 160,000 tons of batteries are generated, and the annual Mn recovery could reach up to 20,000 tons (María et al. 2013). Moreover, a great amount of Mn in waste batteries can be used as a supercapacitor electrode (Sayilgan et al., 2009). Gam et al. reported the use of MnO 2 nanoflowers recovered from Zn-C Batteries (Gomaa et al. 2014). ...
Waste from electrical and electronic equipment exponentially increased due to the innovation and the ever-increasing demand for electronic products in our life. The quantities of electronic waste (e-waste) produced are expected to reach 44.4 million metric tons over the next five years. Consequently, the global market for electronics recycling is expected to reach $65.8 billion by 2026. However, electronic waste management in developing countries is not appropriately handled, as only 17.4% has been collected and recycled. The inadequate electronic waste treatment causes significant environmental and health issues and a systematic depletion of natural resources in secondary material recycling and extracting valuable materials. Electronic waste contains numerous valuable materials that can be recovered and reused to create renewable energy technologies to overcome the shortage of raw materials and the adverse effects of using non-renewable energy resources. Several approaches were devoted to mitigate the impact of climate change. The cooperate social responsibilities supported integrating informal collection and recycling agencies into a well-structured management program. Moreover, the emission reductions resulting from recycling and proper management systems significantly impact climate change solutions. This emission reduction will create a channel in carbon market mechanisms by trading the CO2 emission reductions. This review provides an up-to-date overview and discussion of the different categories of electronic waste, the recycling methods, and the use of high recycled value-added (HAV) materials from various e-waste components in green renewable energy technologies.
... In later years, CB was replaced with porous glassy carbon, graphite, or carbon fibers [2,3]. Due to its high conductivity and good oxygen absorption, graphite has also found application in [4] alkaline batteries, and CB and other carbon varieties in [5] zinc-oxygen batteries and [6,7] fuel cells. This allowed for the construction of cells or sensors free from toxic heavy metals [8,9]. ...
The main purpose of these studies is to compare the diffusion coefficient and ionic conductivity of carbon-based anode materials (graphene and corn starch carbon, graphene nanoplatelets) at different temperatures. The tests were carried out using electrochemical impedance spectroscopy (EIS) in a temperature chamber, which allows the assessment of important parameters during the cell’s operation and optimization, as well as the thermodynamic and kinetic response of the system to various conditions, which are important parameters taking into account the cell’s safety. An interesting method was proposed to determine thermodynamic and kinetic parameters for the development of two models of lithium ion diffusion during half-cell charging. It has been shown that the lithiation process is thermodynamically endothermic and forced. Various carbon materials were used, including corn starch-based carbon as an anode material that equates to the slogans of biodegradability, lower cost and ecology.
Graphical Abstract
... Indeed, the total content of Zn and Mn in spent Mn-Zn batteries (SMZBs) is as high as 50-70% or even higher than primary ores (Sayilgana et al. 2009;Liu 2018), and MZFO as recycling products can be obtained from SMZBs by different methods, such as co-precipitation (Song et al. 2015) and gelatin method (Deng et al. 2018). Generally, a green, simple, and low-cost synthesis process is more conducive to its practical application. ...
Visible-light-driven magnetic heterojunction as a promising photocatalysts has received much attention in environmental remediation. In this work, novel Z-scheme heterojunction MnZnFe2O4@Ag3PO4 (MZFO@APO) magnetic photocatalysts with excellent visible-light-driven photocatalytic activity are successfully constructed and characterized. The photocatalytic activity for phenol degradation is measured, and photodegradation mechanism is investigated with EPR, radical trapping experiments, and LC–MS. It turns out that the heterojunction introduced MZFO exhibits good adsorption effect on visible light and the direct Z-scheme bandgap alignment of MZFO and APO significantly improves charge separation and electron transfer, outperforming that of pure APO. MZFO@APO-40% with 40% APO content shows the rapid photodegradation performance, obtaining a 100% removal efficiency of phenol (25 mg L⁻¹) after 12-min visible light irradiation, and its kinetic constants are approximately 25.3 and 4.9 times higher than that of P25 TiO2 and pure APO, respectively. Especially, MZFO@APO-40% also possesses a high magnetic separation property and can be efficiently reused for 5 cycles. Additionally, EPR and radical trapping experiments confirm that h⁺, O2⁻, and ¹O2 are the main active species in the photocatalytic process. Hydroquinone and small molecular organic acids such as maleic acid and oxalic acid are detected by LC–MS, which further indicates that the pathway of phenol degradation involves hydroxylation, open-ring reactions, and mineralization reactions. The novel addition of MZFO in photocatalyst construction has the potential to promote its application in environmental remediation.
... These batteries are linked with heavy metals such as cadmium, mercury, silver and nickel, which poses an adverse effect on the environment as they end up in landfills when they are not properly recycled or disposed [2]. These metals also affect human health if the batteries corrode or are incinerated thereby polluting the atmosphere, surface and ground water [3]. ...
The incessant nature of electrical power supplies in a developing country like Nigeria, the dependence on dry cell batteries for varying domestic applications such as transistor radios, torchlights, remote controls, amongst others continues to rise unabated. Improper disposal of these batteries poses serious adverse effect on the environment and human health. In this study, over 1000 dry cell batteries were collected from different locations in Ede, Osun State sorted and sectioned to harvest the carbon rods which is a key component of the battery cell. The rods were pulverized for about 15 hours and screened into different particle sizes using standard sieves. The microstructural characterization was investigated using Scanning Electron Microscopy (SEM), Energy Displacer Spectroscopy (EDS), X-ray Diffractometer (XRD), and Ultraviolet (UV) Spectroscopy. High yield graphite powders (98%) were obtained from the processing. Absorption peak was observed at 272.5 nm by UV spectroscopy while XRD plots yielded a narrow peak of 26.60. The characterization results show good agreement with those available in literature.
... It is a well-known fact that the total content of zinc, manganese, and iron in spent Mn-Zn batteries (SMZBs) is as high as 70-80% or even higher than primary ores (Sayilgana et al. 2009;Liu 2018). Therefore, MZFO, as a product recovered from SMZBs, can be obtained by different methods, such as co-precipitation, gelatin method, auto-combustion, etc. ...
To improve the photocatalytic performance of Mn0.6Zn0.4Fe2O4 (MZFO) and ZnIn2S4 (ZIS) for organic pollutants, the p-n MZFO@ZIS heterojunctions with different weight percentage (10 ~ 40%) of MZFO are constructed from spent batteries and added indium ion via a green bioleaching and hydrothermal method. Structural, optical, and photocatalytic properties for the heterojunctions are investigated systematically by XRD, FT-IR, SEM–EDX, TEM, BET, VB-XPS, UV–vis DRS, PL, etc. The results confirm that p–n junction significantly improves the visible light adsorption and the separation efficiency of photogenerated carriers. Specifically, MZFO-25%@ZIS shows the highest photodegradation performance toward Congo red (CR), and its reactive kinetic constant is about 9.6, 7.8, and 7.0 times higher than that of P25 TiO2, MZFO, and ZIS, respectively, and MZFO-25%@ZIS still possesses a high reusability and simple magnetic separation after 5 cycles of reuse. The radical trapping experiments and electronic paramagnetic resonance (EPR) tests show that ·O2⁻, ·OH, and h⁺ are the most important active substance for degrading CR. The pathways for the CR degradation are further proposed based on the intermediate analysis. DFT + U calculations confirm that the high charge density of Zn–O, Fe–O, and Zn–S bonds in the MZFO and ZIS molecules provides the electrons for the sufficient production of free radicals. This work also provides a novel high value-added strategy for the green utilization of spent batteries.
... Electrowinning is widely applied in the hydrometallurgy of primary resources to recover from purified aqueous solutions non-ferrous metals such copper [55], zinc [56], cobalt and nickel [57] upon leaching and solvent extraction. The same technology is also widely utilized in hydrometallurgical processes for the recovery of metal values from secondary resources, as in the case of zinc from alkaline batteries [58] and precious metals from printed circuit boards [59]. Besides, electrowinning is the common industrial practice in the metallurgy of aluminum, where alumina is electro-reduced to aluminum metal onto carbon electrodes in molten salt media [60]. ...
This white paper covers the fundamentals of hydrometallurgical process synthesis, design, and economic evaluation. Metallurgical and Materials Engineering students and engineers with limited process design experience find it particularly useful. It features theory on process synthesis and analysis, material on hydrometallurgical process simulation, and presents a thorough methodology for estimation of capital and operating costs. It also includes the following five detailed process examples modeled and analyzed with SuperPro Designer: 1) Extraction of Lithium from Spodumene Ore, 2) Bio-Hydrometallurgical Recovery of Copper and Gold, 3) Recycling of Solar Photovoltaic Panels, 4) Hydrometallurgical Recycling of Lithium-Ion Batteries and 5) Manufacturing of NMC 811 Cathode Material for Lithium-Ion Batteries. For additional hydrometallurgical examples of SuperPro Designer, please visit https://www.intelligen.com/industries/metallurgy/
... These batteries are linked with heavy metals such as cadmium, mercury, silver and nickel, which poses an adverse effect on the environment as they end up in landfills when they are not properly recycled or disposed [2]. These metals also affect human health if the batteries corrode or are incinerated thereby polluting the atmosphere, surface and ground water [3]. ...
The incessant nature of electrical power supplies in a developing country like Nigeria, the dependence on dry cell batteries for varying domestic applications such as transistor radios, torchlights, remote controls, amongst others continues to rise unabated. Improper disposal of these batteries poses serious adverse effect on the environment and human health. In this study, over 1000 dry cell batteries were collected from different locations in Ede, Osun State sorted and sectioned to harvest the carbon rods which is a key component of the battery cell. The rods were pulverized for about 15 hours and screened into different particle sizes using standard sieves. The microstructural characterization was investigated using Scanning Electron Microscopy (SEM), Energy Displacer Spectroscopy (EDS), X-ray Diffractometer (XRD), and Ultraviolet (UV) Spectroscopy. High yield graphite powders (98%) were obtained from the processing. Absorption peak was observed at 272.5 nm by UV spectroscopy while XRD plots yielded a narrow peak of 26.6 0. The characterization results show good agreement with those available in literature.
... The recycling process of alkaline batteries requires either a hydrometallurgical or a pyrometallurgical process. Despite multiple empirical studies on hydrometallurgical recycling processes (e.g., Liu, 2018;Sadeghi et al., 2020), the pretreatment procedure is complicated and the use of acidic media results in secondary pollution (Sayilgan et al., 2009). A pyrometallurgical process is adopted in the current large-scale industrial recycling technology for alkaline batteries. ...
In the recycling sector, the transition in system networks from centralization to decentralization is an emerging concept. The feasibility to decentralize the recycling of e-waste needs to be analyzed, considering the different characteristics of each municipality. We propose a distributed recycling system for obsolete alkaline batteries using microwave apparatus as a small-scale recycling technology. Firstly, the reactivity of obsolete alkaline batteries with microwave irradiation was empirically examined. In lab-based experiments, pyrometallurgical microwave-based heating successfully separated a mixed sample of Mn3O4 and ZnO contained in obsolete alkaline batteries and recovered MnO and Zn separately, achieving a recovery rate of 97% under an ambient atmosphere. It was also found that the recovery rate of zinc obtained by microwave-based heating is 1.5-fold that using conventional electric furnace-based heating, with less than half of the heating time required. The experimental results were then used to analytically determine the energy efficiency of the distributed recycling system for the treatment of obsolete alkaline batteries with microwave apparatus compared with the centralized recycling system. In an analytical study which considered the characteristics of 1710 municipalities in Japan, it was found that an annual energy and greenhouse gas reduction of 26,500 GJ and 1.54 Gg-CO2eq, respectively, can be achieved at the national level by creating a well-balanced harmony between the centralized and distributed systems. The method applied in this study to determine the effectiveness based on population and intercity transport distance can be readily implemented in any city for the adoption of a distributed recycling system.
... Recycling of metals from e-waste could save up to 90% of natural resources (Zhou et al., 2009). However, unscientifically PCB disposal in the environment creates environmental problems due to the presence of toxic metals (Sayilgan et al., 2009). Hence, metal recycling from waste PCB is the main obligation for economic development as well as for environmental protection (Deng et al., 2007). ...
Water hyacinth (WH), Eichhornia crassipes, is considered a noxious weed in many parts of the world as it grows very fast and depletes nutrients and oxygen rapidly from water bodies, adversely affecting flora and fauna. This study investigates the effect of biogas production in an anaerobic floating drum biogas reactor by using the combination of cow dung and water hyacinth as feedstock. The study was divided into 2 phases. In phase-I, eleven batch reactors are established and feed with varying the combination of cow dung and water hyacinth from 0,10,20,30,40,50,60,70,80,90 and 100% on the dry weight of water hyacinth and cow dung. In phase-II two continuous reactors were established with the best combinations from the phase-I study, the production of biogas was studied by continuous feeding process until the daily production of biogas attains a constant value. The performance of the reactor was monitored by analyzing the daily variations in parameters like VFA (volatile fatty acids) pH, temperature, biogas produced and total solids et.al. The results show that biogas production was possible with water hyacinth and it was seen that the reactors with 90% water hyacinth and 100% water hyacinth gave good results in terms of biogas production. The biogas production rate varies from 20-25L/kg of dry solids of water hyacinth. The percentage of methane found in biogas was 40-45% by using gas chromatography.
... The rod graphite in the discarded dry cell batteries can also be used for the synthesis of graphene (Husein et al. 2021;Bandi et al. 2019). The discarded dry batteries decompose over time, and the metals and chemicals within them can leak into the environment, potentially posing serious health risks to people (Sayilgan et al. 2009). Therefore, the recovery and reuse of graphite resources from discarded dry batteries is not only cost-effective and economically efficient and reduces the expenditure of limited resources but also reduces environmental pollution and manages environmental waste (Ober 2018;Wang et al. 2021b). ...
Extensive studies have shown that doping can enhance the properties of graphene, but the application to real industrial wastewater treatment and theoretical calculations are limited. In this study, the hybrid nanoadsorbent Cu, N co-doped graphene (Cu@NG) was successfully synthesized via green route using carbon rods from waste dry batteries, human urine and copper nitrate, then multiple characterizations, detailed density functional theory (DFT) theoretical calculations and comprehensive actual wastewater tests are performed in environmental applications to investigate the adsorption properties and mechanism. The results showed that Cu@NG surface is mesoporous, decorated with CuO crystals and doped with N atoms. The isotherms and kinetics were simulated by Langmuir and pseudo-second-order models, respectively. The theoretical maximum sorption for MB and CV on Cu@NG is 116.28 mg·g⁻¹ and CV is 86.96 mg·g⁻¹, respectively. Pilot tests with Cu@NG on real textile wastewater showed that COD, BOD and color were removed by 54.2%, 55.2% and 86.4%, respectively. The desorption rate of Cu@NG is approximately above 90% for both MB and CV on Cu@NG after six cycles of treatment. The DFT calculations confirmed the experimental results as MB is more reactive than CV molecules. Besides, interactions have been systematically investigated via topology and natural bond orbital (NBO) analyses. The process mechanism involved mainly electrostatic adsorption, π-π stacking interactions and H-bonding interactions and ion exchange.
Graphical abstract
... If dumped in landfills, these toxic materials can leak into the soil, which can then reach our water supply. If incinerated, toxic fumes are produced, which again have a hazardous impact on the environment and health (Sayilgan et al., 2009). Table 1 summarizes some of these impacts of metal-carbon batteries (Eisler, 1993;Kuchhal and Sharma, 2019;Rajput et al., 2018) and plastics (Bringer et al., 2020;Kik et al., 2020;Okunola et al., 2019) on the environment and health. ...
Human are producing plastic and electronic wastes in huge amount, polluting our environment especially water resources and causing life-threatening complications. On the other hand, the increasing consumption of fossil energy is further damaging our environment. To help mitigate these problems, we present a facile, environment-friendly, and low-cost triboelectric nanogenerator (TENG) by recycling plastic and electronic waste for power generation through biomechanical energy. The proposed graphite and plastic based triboelectric nanogenerator (GP-TENG) is fabricated by recycling the electronic waste (dry cells) to get graphite and the plastic bottles to get plastic. GP-TENG is fabricated by low-cost, facile, and environment-friendly in-house rapid fabrication process which is solvent- and cleanroom-free and doesn’t require specialized equipment and expertise. The output performance of the GP-TENG is systematically studied with an open-circuit voltage of 83.88 V, short circuit current of 101 μA, and maximum output power density of 26.54 μW/cm². To demonstrate its practical applications, a digital calculator, an electronic watch, and nineteen blue light-emitting diodes (LEDs) were powered using GP-TENG. Our approach generates renewable energy by recycling plastics and electronic wastes, and therefore it provides a sustainable and viable path towards the vision of building a green world.
... The columns represent the different battery types that contain the metals marked in the corresponding rows. The list of metals in each battery is obtained from patents and research articles on the construction and recycling of batteries such as chromium (Clough and Wertz, 2001), manganese (Sayilgan et al., 2009) and zinc (Belardi et al., 2011). ...
Fossil fuels are the dominant form of storable energy, but their share in the global energy supply is slowly diminishing due to climate mitigation policies. Alternative energy production from variable renewable energy sources for both stationary and mobile use requires some form of energy storage. Batteries are the current frontrunner for this application, particularly with Li-ion batteries that are reliable and highly efficient. However, batteries themselves have evolved to meet current requirements and expectations. These changes in battery chemistry have shifted the dependency on raw materials used to produce them. Raw materials critical for battery production are subject to supply risk due to their availability or trade policies prompting a need for supply risk assessment. Such resource supply risks depend on the perspective of the importing country or region. By analysing the supply risk of raw materials used in the production of batteries in comparison to fossil fuels, it is possible to understand the shift in risk to storable energy that is underway. In this study, we analyse the supply risk of selected raw materials used in batteries and compare it with the supply risk of fossil fuels for the period 2000 to 2018 from the perspective of the European Union, USA, South Korea, Japan, Canada and Australia using the GeoPolRisk method. Our analysis demonstrates a higher risk of supply for raw materials compared to that of fossil fuels for all the selected territories. Rare earth elements, graphite and magnesium, are amongst the raw materials with the highest supply risk due to their concentrated production in one or only a few countries. Countries have recognised the need for raw material security and made specific policies to ensure secure supply. Raw material security is an emerging concern for all the countries, especially in the case of batteries for major manufacturing nations that are heavily import-dependent. Raw materials producing countries like Canada and Australia focused on stockpiling minerals and minerals exploration while importing countries such as Japan and South Korea are looking for alternate sources for their supply. The results from our analysis suggest that the necessary policy reforms taken for energy security have benefited all the countries with a reduced risk of fossil fuel supply, while similar policies to secure raw materials are discussed but not yet fully implemented.
... In the landfills and dumpsites, which are particularly large in number in developing countries, heavy metals could potentially leach into the soil, groundwater, and surface waters. Moreover, aquifers may be affected by unlined landfills for several years [18]. As mentioned earlier, batteries are composed of several metallic components, including cadmium, lithium, nickel, zinc, copper, lead, chromium, and mercury [7,19,20], and even the trace levels of these elements are extremely harmful to health [9,14,21,22]. ...
Background: Hazardous materials, such as used batteries contain heavy metals and enter the solid waste stream, ending up in landfills. The present study was done to determine the amount of used batteries in Iran and their heavy metal contents in the batteries entering the landfill site in Tabriz. Methods: A questionnaire was applied to assess the current management condition of the used batteries in Tabriz and Ardabil as the representative cities of the entire country. The heavy metal content of 15 AA-sized batteries was determined by inductively coupled plasma. Results: Our findings showed that 14.7% of the used batteries in Iran have been imported, and approximately 76% and 24% of the batteries analyzed at the landfill site were AA-sized and cellphone batteries, respectively. In 60% of the studied batteries, the total heavy metal content was less than 100 mg/kg. Conclusion: The results of this study could be a useful reference for global and local policymakers in developing effective regulations for the use of cleaner materials in the battery industry and controlling the used batteries from their generation to the end of the battery life
... Consequently, battery waste has also risen dramatically. 4 The non-rechargeable batteries, the primary batteries, are widely used as an economical alternative, providing good performance at low cost. 5 Tons of waste metals, such as zinc, manganese, cadmium, chromium, nickel, lead, mercury and lithium, were discharged in Colombia into the environment, sanitary landfills and open dumps between 2002 and 2008, referring to batteries disposed of by customers along with domestic waste. ...
A new multifunctional composite material manufactured from vinyl-acrylic resin and mixed with battery waste powders containing graphite, manganese oxide, and zinc oxide particles has been developed. The battery waste (BW) was obtained from a recycling company as a byproduct from the grinding process of primary batteries (alkaline and zinc carbon batteries). In addition, 24 and 28 AWG copper wires (CuW) were obtained from recycling circuit waste, which were added in 5, 10 and 15 wt% contents to form composite materials, with all CuW of 2 mm length. These formulations were characterized using scanning electronic microscopy, compression, density, and piezoresistivity tests. When copper was added to the composite material, the behavior of the sensor was linear, a characteristic desired in piezoresistive sensors since they do not need any additional configuration to obtain said linearity. As the percentage of copper increased, the sensitivity of the sensor decreased and the conductivity increased.
... Zinc-carbon dry cells are commonly used, due to their easy availability and low cost, in various household applications such as flashlights, remote controls, clocks, radios, tape recorders, cameras, electric toys, and other purposes [1]. However, these cells are primary batteries that cannot be recharged further after use, and the only option left is that the used cells should be discarded. ...
Development of high-performance energy storage devices is a vital research area to meet the present-day energy demand. In the work carried toward the development of high-performance electrodes, recently identified materials are hybrid materials. In this direction, we select a hybrid of sulfonated reduced graphene oxide and polyaniline, which is prepared by the conversion of graphite rod used in the zinc-carbon cell to graphene oxide, then to reduced graphene oxide followed by sulfonation, and finally, incorporation in the polymerization of aniline. IR, XRD, TGA, and EDAX analyses support the formation of hybrid. The electrochemical performances in terms of specific capacitance, rate capability, cycle stability, etc., of the hybrid electrode are higher than its components. Excellent Ragone plot is observed, i.e., less change in energy densities of 22, 22, 21, 20, and 20 W h kg⁻¹ at power densities of 150, 300, 600, 900, and 1200 W kg⁻¹, respectively. Specific capacitance value decreases with cycle numbers from 386 at the 2nd cycle to 320 F g⁻¹ at 1400 cycles, then increases to 342 F g⁻¹ at 2000th cycle due to wettability of the hybrid. Besides, the hybrid shows less solution and charge-transfer resistance with a high phase angle value of 79°.
Graphical abstract
... Recycling of metals from e-waste could save up to 90% of natural resources (Zhou et al., 2009). However, unscientifically PCB disposal in the environment creates environmental problems due to the presence of toxic metals (Sayilgan et al., 2009). Hence, metal recycling from waste PCB is the main obligation for economic development as well as for environmental protection (Deng et al., 2007). ...
Among the listed aquatic weeds Water hyacinth (Eichhornia crassipes) is one of the weeds that can double its size in 6–28 days, by forming a mat like structure on the water obstructing the sunlight. This plant affects the aquatic ecosystem (Malik, 2007). Any fresh water body has a potential threat from these types of aquatic weeds. Several control measures are added to the scientific journals among them one of the methods is using these weeds as a feed stock for the anaerobic digestion to produce biogas. Water hyacinth is suitable for anaerobic digestion process due to its carbon nitrogen ratio. Using weeds as a feedstock and converting them to useful bio-fuel may reduce the load on the conventional power generation processes from air, water and solar energy sources (Rao et al., 2010). The biogas producing capacity of the biodegradable wastes like weeds and agricultural wastages is estimated to be 40,734 m³ year in India (Rao et al., 2010). By using the mixture of cattle dung and Water hyacinth will lead to better biogas production (Kumar, 2005). The present study summons the usage of Water hyacinth in anaerobic digestion process. For better yield of biogas, cow dung was used in combination with Water hyacinth.
... Recycling of metals from e-waste could save up to 90% of natural resources (Zhou et al., 2009). However, unscientifically PCB disposal in the environment creates environmental problems due to the presence of toxic metals (Sayilgan et al., 2009). Hence, metal recycling from waste PCB is the main obligation for economic development as well as for environmental protection (Deng et al., 2007). ...
Plastic waste is one of the major environmental concerns. Eight million to 12.7 million tonnes are dumped into the sea (https://www.sas.org.uk/our-work/plastic-pollution/plastic-pollution-facts-figures/). If plastic wastes are thrown in the land, it makes the soil less fertile and it also pollutes water and harms sea life. Plain concrete has a limited ductility and resistance to cracking (https://theconstructor.org/concrete/). The addition of fibres can improve the properties of concrete. These fibres are uniformly dispersed into the concrete mix which increases its structural integrity. This type of concrete is known as fibre reinforced concrete. This can be natural, animal fibres or polymers. Incorporating plastic into concrete is one possible environmentally friendly approach for their safe disposal. Polyethylene terephthalate is one of the most important and extensively used plastics in the world. PET (polyethylene terephthalate) is a form of polyester that is extracted or moulded into plastic bottles and containers (https://www.worldbank.org/en/news/immersive-story/2018/09/20/what-a-waste-an-updated-look-into-the-future-of-solid-waste-management). PET as fibre reinforcement in structural concrete can provide crack control and ductility enhancement for concrete (Kim et al., 2010). In recent years, a lot of experimental studies were carried out on using waste plastic bottles. The use of PET bottle fibres has a positive effect on the properties of the concrete (Subramani and Fizoor Rahman, 2017). PET-fibres as the partial replacement of aggregate in the Portland cement aggregate concrete. It shows an increase in compression and tensile strength (Ramadevi and Manju, 2012). Akcaözoglu et al. (2010) shredded waste PET bottles granules and used it as a lightweight aggregate in mortar. It was concluded that the use of shredded waste PET granules as aggregate resulted in the production of structural lightweight concrete. The PET-fibres increase the durability of concrete and it can be used to improve the ductility of the concrete (Foti, 2011). Long term durability performance of recycled PET-fibre reinforced cement composite can be achieved (Won et al., 2010). In this study, the effect of different sizes of PET fibres on concrete was evaluated. These PET fibres are produced from PET bottles. Also, the study of strength and failure mode of PET-fibres reinforced concrete is performed.
In the modern era, realizing highly efficient supercapacitors (SCs) derived through green routes is paramount to reducing environmental impact. This study demonstrates ways to recycle and reuse used waste dry cell anodes to synthesize nanohybrid electrodes for SCs. Instead of contributing to landfill and the emission of toxic gas to the environment, dry cells are collected and converted into a resource for improved SC cells. The high performance of the electrode was achieved by exploiting battery-type polyoxometalate (POM) clusters infused on a reduced graphene oxide (rGO) surface. Polyoxometalate (K5[α-SiMo2VW9O40]) assisted in the precise bottom-up reduction of graphene oxide (GO) under UV irradiation at room temperature to produce vanadosilicate embedded photo-reduced graphene oxide (prGO-Mo2VW9O40). Additionally, a chemical reduction route for GO (crGO) was trialed to relate to the prGO, followed by the integration of a faradaic monolayer (crGO-Mo2VW9O40). Both composite frameworks exhibit unique hierarchical heterostructures that offer synergic effects between the dual components. As a result, the hybrid material's ion transport kinetics and electrical conductivity enhance the critical electrochemical process at the electrode's interface. The simple co-participation method delivers a remarkable specific capacity (capacitance) of 405 mA h g-1 (1622 F g-1) and 117 mA h g-1 (470 F g-1) for prGO-Mo2VW9O40 and crGO-Mo2VW9O40 nanocomposites alongside high capacitance retentions of 94.5% and 82%, respectively, at a current density of 0.3 A g-1. Furthermore, the asymmetric electrochromic supercapacitor crGO//crGO-Mo2VW9O40 was designed, manifesting a broad operating potential (1.2 V). Finally, the asymmetric electrode material resulted in an enhanced specific capacity, energy, and power of 276.8 C g-1, 46.16 W h kg-1, and 1195 W kg-1, respectively, at a current density of 0.5 A g-1. The electrode materials were tested in the operating of a DC motor.
The rechargeable battery market has almost doubled in 15 years. Regardless of the type of batteries, their limited lifespan means that sooner or later they will constitute a mass of waste whose management is problematic as their content is high in elements and metals of high economic interest, but also toxic to the environment. This project is to optimize the solubilization conditions for rare earth elements (REEs) and other metals from waste nickel-metal hydride (Ni-MH) batteries. The Ni-MH battery powder used contained the following main elements: Ni (548 g/kg), La (45 g/kg), Co (32 g/kg), Zn (22 g/kg), Nd (15 g/kg), Sm (12 g/kg), and Ce (11 g/kg). The metals were solubilized in the presence of sulfuric acid. Acid concentration, solids concentration, leaching time, and temperature were optimized using the Box-Behnken design methodology. The optimal conditions identified are an H2SO4 concentration of 2 M, a S:L ratio of 10% (w:v), a leaching temperature of 60oC and a reaction time of 90 min. These conditions make it possible to solubilize 81% Ni, 99% Co, and 70% REEs, while the mathematical model predicted 83% Ni, 100% Co, and 80% REEs respectively. The process was also operated in counter-current leaching mode with the optimal parameters. The high solubilized yields obtained after five loops for all metals, REE and the significant reduction of water consumption confirm that this process leaching can be apply for industrial application.
Due to ecotoxicity, zinc (Zn) as a heavy metal from electronic waste (e-waste) has been a source of pollution to soil and water for several decades. This study proposes a solution to this serious environmental problem via a self-consumed strategy to stabilize Zn in anode residues. This unique method uses cathode residues from spent zinc-manganese oxide (Zn-Mn) batteries as a stabilized matrix via thermal treatment. More specifically, the strategy incorporates zinc metal into a chemically durable matrix comprised of a lattice of AB2O4 compounds. Results demonstrate that 5-20 wt% of anode residue were fully incorporated into the cathode residue to form a Mn3-xZnxO4 solid solution after sintering at 1300 ℃ for 3 h. The lattice parameters of the Mn3-xZnxO4 solid solution reveal an approximately linear decreasing evolution with the addition of anode residue. To determine the occupancy of Zn in the crystal structure of the products, we used Raman and Rietveld refinement processes; the results reveal that Mn2+ in the 4a site was gradually replaced by Zn2+. We then used a prolonged toxicity leaching procedure to evaluate the Zn stabilization effect after phase transformation; this showed that the Zn leachability of sintered anode-doped cathode sample was over 40 folds lower than that of untreated anode residue. Therefore, this study presents an economical and effective strategy for mitigating the presence of heavy metal pollutants derived from e-waste.
Recovery of valuable metals from used portable batteries is gaining widespread importance owing to the conservation of natural sources and possible environmental pollution from these batteries. In this paper, zinc (Zn) and manganese (Mn) recovery from waste zinc–carbon (Zn–C) batteries was investigated. For this purpose, two-stage leaching experiments were conducted in the laboratory. In the first stage, only sulfuric acid (H2SO4) solution was used, and in the second stage, ferrous ion (Fe2+) was added to the H2SO4 solution as a reducing agent. The burnt and wet sieved battery powder was obtained from manually disassembled waste Zn–C batteries. Particle size fraction of -75 + 53 µm battery powder contained 23.75% Zn and 48.47% Mn. Leaching experiments performed with a solid-to-liquid ratio of 4 g/L showed that Zn and Mn were leached with a recovery of 100% and 58.55%, respectively, using 400 rpm stirring speed, 0.25 M H2SO4 solution, and 70 °C temperature. Reductive leaching experiments showed that all of the Mn was recovered in 0.25 M H2SO4 solution using 3.6 × 10–2 M Fe2+ as a reducing agent at 60 °C temperature.
Nowadays, the research on wearable electronics have received tremendous attraction because of their potential applications in personalized health monitoring and treatment, energy conversion and storage, and human-machine interface system. Herein, we report a facile route for the fabrication of electrically conductive cotton fabric with excellent joule heating and high electromagnetic shielding performances using graphene oxide (GO) and silver nitrate (AgNO 3 ). The GO used in this study is exclusively synthesized from spent batteries in order to minimize the environmental pollution. The surface morphology, elemental analysis, electrical conductivity, thermo-heating behavior and electromagnetic shielding performance have been studied systematically. Due to the high electrical conductivity, the GO-Ag coated cotton with 5 wt% of GO reached high surface temperature of 117.8°C within 35 s, and also it exhibits high electromagnetic interference shielding efficiency value of 79.08 dB. The high flexibility, excellent conductivity, electromagnetic shielding efficiency and joule heating performance of GO-Ag coated cotton fabric suggesting that the GO synthesized from spent batteries will be a potential and valuable resource for the new generation of wearable electronics.
The recovery of valuable metals from waste batteries gains more importance over time due to the decrease in natural resources and the possible harms of these to the environment. Economic benefits can also be obtained by recycling waste batteries. The recovery of valuable metals such as manganese (Mn) and zinc (Zn) in waste zinc-carbon (Zn-C) batteries has attracted the attention of many researchers. Hydrometallurgical methods are used as an effective method for the recovery of metals from waste Zn-C batteries. In this paper, kinetics of Mn and Zn dissolution from waste Zn-C batteries in sulfuric acid (H2SO4) solution was studied. The maximum Mn and Zn dissolution recoveries in 60 min leaching time were achieved using 400 rpm stirring speed, 0.25 M H2SO4 concentration, 70°C temperature and −53 µm particle size. In these conditions, Mn and Zn dissolution recoveries were obtained as 62.56% and 100%, respectively. To determine the dissolution kinetics of Mn and Zn, a new equation of shrinking core model was used and determined that Mn and Zn were dissolved in H2SO4 solution by interfacial mass transfer and diffusion across the product layer.
Spent batteries are one of the most problematic in the waste management sector. The number of batteries grows annually, where only a few percent of materials are successfully recovered. Battery waste recovery is challenging for its complex composition including porous electrodes and toxic electrolytes. In this work, we refer to the acid leaching of spent battery waste for the recovery of Li and Co. Spent batteries were discharged, mechanically disassembled, and electrode powder was treated chemically. The leaching agents were mild organic acids like glutaric, lactic, and formic acids, and/or sulphuric acid. The morphology of spent electrode carbon-based powder was determined with SEM. The post-leaching solutions were studied within the ICP-OES to estimate the % of the recovery rate of certain metals. The recovery rate reaches even 59% and 82% of Co and Li, respectively, when the acid-leaching bath contained sulphuric acid, hydrogen peroxide, and glutaric acid.
The energy consumption of the heating, ventilation, and air-conditioning
systems
(HVAC)
represents
around
40%
of
energy
consumption
in
Europe.
According to
several
studies,
evaporative
cooling
technology
presents
an
interesting
solution to
conventional
air-cooling
systems
in
terms
of
energy
efficiency.
However,
few
research
works
analysed
water-related
indexes
in
indirect
evaporative
coolers
(IEC).
So,
the
main
objective
of
this
research
study
was to
evaluate
the
environmental
and
the
water-use
impact
on
IEC
systems
in
the
Mediterranean
climate
area.
Several
experimental
tests
were
carried
out to
fit
the
empirical
models
of
cooling
capacity,
power
consumption
and
water
consumption
of
an
IEC.
These
models
were
used
for
annual
energy
simulations.
Several
key
performance
indices
(KPI)
were
obtained
with
the
results
of
these
annual
simulations.
These
KPIs
for
the
IEC
system
were
evaluated
for
four
different
climate
zones.
Based
on
energy
simulations,
the
IEC
system
reached
the
highest
values
of
annual
seasonal
energy
efficiency
ratio
(SEER),
3.8,
and
cooling
capacity
per
unit
of
water
consumed
(KPIC-W),
0.23
kWh/l,
for
the
Athens
weather
conditions,
but
also
the
highest
value
of
annual
CO2
emissions
(ĖCO2),
3378.4
kgCO2/year.
The
results
showed
that
the
IEC
systems
reached
the
highest
values
of
environmental
impact
and
water-
use efficiency for hot climate zones.
Hazardous waste alkaline batteries and waste fatty acids significantly threaten the environment. In this study, waste alkaline batteries were simply transferred to r-MnZn catalysts, which were then applied in the ketonization of fatty acids. The assessment results show that r-MnZn can efficiently convert n-octanoic acid to 8-pentadecanone. The conversion and yield are evaluated as 100% and 92.9%, respectively, which are much better than those of TiO2, ZrO2, CeO2 and other metal oxides. The excellent catalytic efficiency is derived from the MnO2 nanorods in r-MnZn materials which are characterized by XRD, TEM, and XPS. In addition, when using different kinds of fatty acids in ketonization, longer carbon chains require a higher activation energy, and the conversion of fatty acids was lower. Furthermore, the ketone products have a short carbon chain that induces side reactions, leading to a low yield. The above results indicate that r-MnZn is an efficient catalyst applied in the ketonization of fatty acids.
Spent zinc–manganese batteries contain heavy toxic metals that pose a serious threat to the environment. Recovering these metals is vital not only for industrial use but also for saving the environment. Recycling metal from spent batteries is a complex task. In this study, machine-learning-based predictive models are developed for predicting metal recovery from spent zinc–manganese batteries by studying the energy substrates concentration, pH control of bioleaching media, incubating temperature and pulp density. The main objective of this study is to make a detailed comparison among five machine learning models, namely, linear regression, random forest regression, AdaBoost regression, gradient boosting regression and XG boost regression. All the machine learning models are tuned for optimal hyperparameters. The results from each of the machine learning models are compared using several statistical metrics such as R2, mean squared error (MSE), mean absolute error (MAE), maximum error and median error. The XG Boost regression model is observed to be the most effective among the tested algorithms.
Mn-Fe bimetallic oxide has been employed as an outstanding peroxydisulfate (PDS) activator, but the underlying mechanism is still controversial. In this work, Mn0.27FeO4.55 (MFBO) was synthesized using the recovered waste alkaline battery and its catalytic activity and mechanism for PDS activation were explored in detail. Results show that MFBO exhibited a higher catalytic activity than the individual single metal oxides (FeOx and Mn2O3) due to the synergistic effect between Fe and Mn elements. The removal efficiency of bisphenol A (BPA) with an initial concentration of 10 mg/L reached 98% within 90 min in the presence of 0.5 g/L MFBO and 2.0 mM PDS. Moreover, the MFBO maintained high stability and reusability even after being recycled for five times. With the aid of a series of experiments and ex-situ/in-situ characterizations, a non-radical PDS activation mechanism was proposed, in which organic contaminants would be oxidized through a direct electron transfer pathway mediated by the metastable reactive complexes (MFBO-PDS*). Notably, the MFBO/PDS system revealed selective oxidation towards different organic pollutants and the reaction rates were closely related to their structures and properties. The research provided an effective alternation process for application of the waste battery, as well as developed a novel perspective for removal of recalcitrant aqueous contaminants through a non-radical mechanism.
Sustainable energy storage medium has increased significantly in recent times. Air contamination, which is widely considered to be harmful to an ecological niche, has fuelled the growth of sustainable energy sources. On the other hand, adopting sustainable energy technology can create significant issues for keeping the grid stable. With variations in the output of renewable energy sources, storage is essential for power and voltage balancing. Storage of electricity is necessary for energy management, frequency control, peak shaving, load balancing, periodic storage, and backup production in the event of a power outage. As a result, storage technologies have received increasing attention and have evolved into something more than a need in today's world. This article provides a thorough assessment of battery energy storage systems. In addition to describing the features and capabilities of each type of battery storage technology, it also discusses the benefits and drawbacks of each innovation when contrasted to other storage mediums. There are comparative charts with many features of each storage technique provided and descriptions of the various uses of energy storage methods. Furthermore, The current work discussed the batteries' strengths, weaknesses, opportunities, and threats (SWOT) analysis in power transmission.
Advances in biohydrometallurgical technology have made it possible to utilize the microorganisms and their metabolites in the recovery and resource recycling of metals from secondary sources like industrial wastes. Various strategies have been developed to apply these microorganisms to improve the efficiency of the method. Use of microbial consortia is one of the promising strategies. Microbial consortia can be applied in various approaches and this chapter discusses the current applications and some promising emerging technologies that can assist in enhancing the bioleaching performance. Furthermore, interesting applications of microbial consortia for metal recovery from different industrial wastes are described along with the role of consortia and mechanisms involved.KeywordsMicrobial consortiaBioleachingIndustrial wasteMetal
Green, simple and high value-adding technology is crucial for realizing waste batteries recycling. In this work, the magnetically recyclable Mn0.6Zn0.4Fe2O4@Zn0.9Mn0.1O ([email protected]) heterojunctions are prepared from waste Mn–Zn batteries via a green bioleaching and sample co-precipitation method. The as-prepared catalysts with different Zn0.9Mn0.1O weight percentage (25%, 50% and 75%) have been comprehensively characterized in structure, optics, photoelectrochemistry and photocatalytic activity. Characterization results indicate that [email protected] heterojunctions with the core-shell structure, demonstrates excellent absorption intensity in the visible light region, outperforming that of individual ZnO and Zn0.9Mn0.1O. Especially, the staggered bandgap alignment of Mn0.6Zn0.4Fe2O4 and Zn0.9Mn0.1O greatly enhances electron transfer and charge separation in the binary heterojunction system. The optimized [email protected]%-ZMO shows the highest photodegradation performance toward methylene blue (MB) under the visible light irradiation, with a 99.7% of photodegradation efficiency of 20 mg L⁻¹ of MB within 90 min, and its reactive kinetic constants is about 7.2, 10.8 and 21.7 times higher than that of Zn0.9Mn0.1O, P25 TiO2 and Mn0.6Zn0.4Fe2O4, respectively. The MB photocatalytic mechanism is investigated in the scavenger and 5,5-dimethylpyrroline-N-oxide (DMPO) spin-trapping electron spin resonance (ESR) experiments, and h⁺ and *O2⁻ are identified as the major active species for MB degradation. In addition, [email protected]%-ZMO also exhibits a good reusability and high magnetic separation properties after six successive cycles. This new material indicates the advantages of low costs, simple reuse and great potential in application.
The information revolution has shown augmented growth in the production of information technology (IT) equipment like personal computers and mobile phones in addition to other electrical and electronic equipment (EEE) from the last two decades. Due to the higher obsolescence rate of EEE, waste EEE (WEEE) or electronic waste (e-waste) is presently growing at a faster rate than the municipal waste streams (Grossman, 2007). Baldé et al. (2017) estimated the global WEEE generation of about 44.7 million tonnes (Mt) in 2016 and expected to grow to 52.2 Mt by 2021. According to the recent joint study of the ASSOCHAM-NEC (2018), India generates a total of 2.0 Mt of e-waste. Each EEE contains a printed circuit board (PCB) as the main working component with heterogeneous elemental content, which includes base, toxic and precious metals. Studies have reported that obsolete computer PCB contains metal in the range of 20–24% Cu, 1–3% Ni, 0.6–6.3% of Pb, which are comparatively higher than the mineral ores. Because of their high content of base and heavy metals besides some amount of precious metals, make it valuable metal resource (Bandyopadhyay, 2008; Priya and Hait, 2018a). Recycling of metals from e-waste could save up to 90% of natural resources (Zhou et al., 2009). However, unscientifically PCB disposal in the environment creates environmental problems due to the presence of toxic metals (Sayilgan et al., 2009). Hence, metal recycling from waste PCB is the main obligation for economic development as well as for environmental protection (Deng et al., 2007). Metal recycling techniques like pyrolysis and hydrolysis are expensive, energy-intensive and generate secondary pollution (Ilyas et al., 2010; Pant et al., 2012; Priya and Hait, 2017). In the case of pyrometallurgy, heat treatment is given to wastes for metal recovery and the process is fast and efficient but emits toxic gases and requires high energy for operation. In hydrometallurgy, chemicals like mineral acids, ligand are used to recover metals efficiently from e-waste, however toxic nature of these chemicals is a major concern for their applicability (Priya and Hait, 2017). Effluent generated from these conventional metallurgical processes, which further needs treatment to dispose of into the environment safely (Priya and Hait, 2017). To overcome these aforementioned drawbacks, nowadays researchers are focusing on the metal recycling process, which is efficient as well as environmentally friendly.
In this paper several leaching tests were performed to optimize the leaching section of a hydrometallurgical process for the recycling of alkaline and zinc-carbon batteries. Zinc and manganese oxides were dissolved by an acidic-reductive leaching using sulphuric acid and oxalic acid as reductant. Leaching tests were developed according to a full factorial design. The operational variables were pulp percentage, sulphuric acid concentration, temperature and oxalic acid concentration. Additional tests were performed to evaluate the precipitation rate of Mn and Zn oxalates. Finally a hydrometallurgical process were proposed for the recycling of alkaline and zinc-carbon batteries, in which Zn and MnO2 are recovered from purified solution by electrowinning: Zn is recovered as metallic compound, while Mn can be recovered as electrolytic manganese dioxide (EMD), but recovery of further manganese compounds is possible with simple process changes.
In this work, hydrometallurgical processes have been applied starting from spent alkaline batteries.
Main aim of the research was to develop a preliminary experimental work to recover selectively MnO2 and Zn from leaching solution containing Mn and Zn, both at concentration of 10 g dm-3, by electrolysis, with the scope to apply electrochemical technologies for Zn and Mn recovery from exhaust batteries.
The results have demonstrated the technical feasibility of the application of the mentioned technologies; in fact, high recoveries of manganese and zinc dissolved in solution were achieved (97 % MnO2 and 98.50 % Zn).
This paper presents the experimental results for the leaching of printed circuit boards (PCB) from obsolete computers for extracting and recovering tin and copper by means of leaching followed by precipitation. Printed circuit boards were dismantled, cut into small pieces, and fed into a cylinder mill. The powder obtained was leached by using the aqueous solutions 2.18N H2SO4, 2.18N H2SO4 + 3.0N HCl, 3.0N HCl, and 3.0N HCl + 1.0N HNO3. The lowest values for the percentage of metal extraction were obtained with 2.18N H2SO4 (2.7% for Sn and lower than 0.01% for Cu), while the 3.0N HCl + 1.0N HNO3 leach system exhibited an extraction of 98% for Sn and 93% for Cu. Precipitates were obtained at different pH values by neutralizing the leach liquors using NaOH. The 3.0N HCl + 1.0N HNO3 leach system presented the highest recovery values from the powder feed (84.1% for Sn and 31.9% for Cu), as well as from the leach liquor (85.8% for Sn and 34.3% for Cu).
The fly ash generated from oil burning is collected with a dust collector installed on a boiler. Recently, The necessity of developing a new process for recycling fly ash has recently received considerable attention due to the rather short life of landfills used for the disposal of a fly ash. Many tests have therefore recently been carried in order to develop a recycling process for useful components such as V and Ni following the concept of zero emission. The results can be summarized as follows: (1) V ions in the fly ash can be leached out by mixing with an equal quantity of water and most of the components that remain in the residue can then be leached out by adding an: aqueous ammonia solution. Using this two-stage leaching method, all components of interest can be leached out without heating or using significant amounts of chemicals. (2) It was possible to recover of Ni and V ions by a solvent extraction method which resulted in a high purity of the recovered compounds. (3) The sulfate ions, Mg ions, and ammonium ions that remained in the solution after the solvent extraction process to recover Ni and V ions were recoverable through a crystallization and distillation process as calcium sulfate, magnesium hydroxides and aqueous ammonia solution, respectively. (4) Based on results of this work, a new recycling system which does not produce secondary waste was developed for fly ash generated from oil burning.
Cyanide has been recognized for a long time as a powerful lixiviant for gold and silver, forming very stable cyano complexes with both metals. While cyanide is very effective in leaching free milling ores, there are certain classes of gold and silver ores (i.e., carbonaceous, pyritic. arsenical, manganiferous, cuperferous) that are considered refractory to conventional cyanidation dissolution. Recently there has been considerable effort directed towards new and improved reagents for leaching these difficult-to-treat ores and concentrates. A large portion of this effort has been devoted to finding alternative lixiviants that might compete with conventional cyanidation. Furthermore, there is a general interest in developing non-toxic environmentally safe substitutes for cyanide.There are a number of reagents that form stable complexes with gold and silver e.g., thiourea, thiosulfate, halides, malononitrile, acetonitrile and polysulfides. The chemistry of gold and silver dissolution using alternative lixiviants is discussed in this paper. Special emphasis is given to the application of Eh-pH diagrams to interpret the dissolution behavior.
In this paper a recycling process for the recovery of zinc and manganese from spent alkaline and zinc–carbon batteries is proposed. Laboratory tests are performed to obtain a purified pregnant solution from which metallic zinc (purity 99.6%) can be recovered by electrolysis; manganese is recovered as a mixture of oxides by roasting of solid residue coming from the leaching stage. Nearly 99% of zinc and 20% of manganese are extracted after 3h, at 80°C with 10% w/v pulp density and 1.5M sulphuric acid concentration. The leach liquor is purified by a selective precipitation of iron, whereas metallic impurities, such as copper, nickel and cadmium are removed by cementation with zinc powder. The solid residue of leaching is roasted for 30min at 900°C, removing graphite completely and obtaining a mixture of Mn3O4 and Mn2O3 with 70% grade of Mn. After that a technical-economic assessment is carried out for a recycling plant with a feed capacity of 5000ty−1 of only alkaline and zinc–carbon batteries. This analysis shows the economic feasibility of that plant, supposing a battery price surcharge of 0.5€kg−1, with a return on investment of 34.5%, gross margin of 35.8% and around 3 years payback time.
This paper concerns the recovery of zinc and manganese from alkaline and zinc-carbon spent batteries. The metals were dissolved by a reductive-acid leaching with sulphuric acid in the presence of oxalic acid as reductant. Leaching tests were realised according to a full factorial design, then simple regression equations for Mn, Zn and Fe extraction were determined from the experimental data as a function of pulp density, sulphuric acid concentration, temperature and oxalic acid concentration. The main effects and interactions were investigated by the analysis of variance (ANOVA). This analysis evidenced the best operating conditions of the reductive acid leaching: 70% of manganese and 100% of zinc were extracted after 5h, at 80°C with 20% of pulp density, 1.8M sulphuric acid concentration and 59.4gL−1 of oxalic acid. Both manganese and zinc extraction yields higher than 96% were obtained by using two sequential leaching steps.
Discussed is the INMETCO processing of electric arc furnace (EAF) baghouse dusts from the specialty-steel and low-alloy industries. In addition, the INMETCO process has been modified to recover nickel, chromium and iron from many other waste materials including: pickling solutions or filter cakes, spent nickel and chromium plating baths, carbon refractories from pickling tanks, and superalloy wastes including baghouse bags. INMETCO is the only North American company presently capable of recycling nickel-cadmium batteries by high-temperature metals recovery. This process and the details of INMETCO's best demonstrated available technology (BDAT) test program are discussed.
Batrec AG operates an industrial plant for recycling of used dry batteries with a production capacity of 3200 tons per year. The process consists essentially of the following three process stages: • Pyrolysis of the organic part of the waste in the shaft furnace at temperature up to 700°C where the mercury is also evaporated. • Reduction of the metallic parts in the melting furnace at temperature of 1500°C. The metals are either molten (Fe, Mn, Ni) or evaporated (Zn, Pb, Cd). • Recovery of the gaseous metals (Zn, Pb, Cd) in the splash condenser. This Technology permit us to treat hazardous waste without the formation of new waste. As an demand we have seen, that other heavy metal containing wastes could be treated in this plant. Today Batrec AG is able to treat the most mercury contaminated wastes from dental waste to track field coverings and from sludge to contaminated scrub.
Material and energy resource consumption is on the rise in both the industrialized and developing world (e.g., countries like India and China). In order to sustain this growth and provide resources for future generations, there is a need to design products that are easy to recover and recondition, thus enabling multiple use cycles. Processes are needed that can achieve this multi-use while producing zero (or very near zero) waste. There exist a number of barriers and challenges to achieving this vision of multi-use with zero waste; one such challenge is the development of a product recovery infrastructure that will minimize short-term impacts due to existing products and will be robust enough to recover products of the future. This paper identifies the barriers to developing such a recovery and reuse infrastructure. The aim is to achieve product multi-use and zero waste.
The Placid process is a hydrometallurgical technique for recovering lead from spent battery pastes. The process, when used in combination with a pyrometallurgy process, has the potential to recover high-purity lead and offers significant environmental improvements.
In this work, zinc from the spent Zn–MnO2 batteries is recycled. Ionic zinc is recovered from acidic or alkaline solutions using a galvanostatic technique. An optimum current density between 10.0 and 25.0 mA cm−2 was obtained for recovery of ionic zinc from acidic solutions. The optimum current density is equal to 15.0 mA cm−2 for zinc electrodeposition from alkaline solution. The charge efficiency is 80.0% and decreases with increase of current density. In acidic solutions, hydrogen adsorption catalyse Zn2+ electrodeposition. In alkaline solutions, a parallel reaction of the hydrogen evolution inhibits zincate electrodeposition.
Aqueous SO2 leaching studies of Nishikhal manganese ore containing 32.5% Mn and 16.5% Fe were carried out at atmospheric pressure and room temperature using H2SO3. The variables considered were SO2 concentration, solid-to-liquid ratio, sulphuric acid concentration and duration of leaching. Regression equations for extraction of manganese and iron were determined from 24 full factorial design. The effect of variables on extraction of manganese were independent of each other within the range of variables chosen for experiment. It was found that 95% of manganese could be extracted in 15 min from −150 μm ore with twice the stoichiometric quantity of SO2 required for dissolution of manganese. The quantity of SO2 present in the solution is the controlling factor in the extraction of manganese.
A novel energy-saving hydrometallurgical recovery process for copper from electronic scrap employing the Cu(I)-ammine complex has been presented on the basis of a thermodynamic consideration. In order to experimentally explore the feasibility of the leaching stage in this process, the copper leaching behavior from a printed circuit board (PCB) in ammoniacal alkaline solutions has been investigated under a nitrogen atmosphere. Copper in PCB was oxidized by Cu(II) to form Cu(I)-ammine complex ions. The leaching reaction can be expressed as: Cu + Cu(NH3)(4)(2+) = 2Cu(NH3)(2+). The Cu(II)-ammine complex significantly enhanced the leaching rate, while the Cu(I)-ammine complex slightly depressed it. Crushing of the PCB effectively enhanced the leaching rate, because the exposed metallic copper area is increased by the crushing. The effect of temperature on the leaching rate was insignificant. Consequently, the feasibility of the leaching stage in the proposed copper recovery process has been experimentally confirmed.
The improving awareness of environmental problems associated with the toxicity of heavy metals keeps the recycling of spent nickel–cadmium batteries an important assignment due to the presence of cadmium, nickel and cobalt on the electrode material. While cadmium from batteries is one of the major sources of cadmium contamination of the environment, the other heavy metals contained on the electrode material have a considerable economic value. Therefore a complete and valorising solution to the management of this type of residues is not possible through the existing pyrometallurgical processes because the treatment of complex materials in order to recycle all materials is difficult. An integrated process based on physical and hydroelectrometallurgical operations seems to be more efficient because it is possible to recover the three metals, Cd, Ni and Co, present on the electrode material. The study here presented deals with the first chemical stage of an integrated process, the leaching of spent nickel–cadmium electrodes with sulphuric acid. The electrode materials essentially composed of Ni, Cd and Co hydroxides were readily solubilised in 0.5 h with low acid concentrations (pH∼1) at ambient temperature. At higher pH values the solubilisation of metal hydroxides was inefficient, except when using long residence times. The leaching of nickel present in the metallic form, in the electrodes, was more difficult due to kinetic constraints, applying high temperature (e.g. 95 °C) and acid concentration (e.g. 2.5 M H2SO4) in order to obtain complete conversions in acceptable time (∼4 h).
The effects of adding carboxylic acid to the leaching media upon the extraction of niobium and tantalum from a ferrocolumbite are studied. Leaching tests were carried out with a pressure reactor in hydrofluoric and carboxylic acids media. Comparative experiments were performed modifying the following variables: temperature, hydrofluoric acid concentration, solid/liquid ratio and carboxylic acid type and concentration.The reagents and products have been characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDXS), X-ray fluorescence (XRF), X-ray diffraction (XRD), and surface area (BET) measurement.The results obtained show an increase in the niobium and tantalum dissolution when carboxylic acids such as oxalic and tartaric acids are added to the reaction media. The addition of tartaric acid also increases the iron and manganese recovery. The addition of oxalic acid decreases the extraction of manganese, while the extraction of iron is almost nonexistent under certain conditions due to the formation of an insoluble compound that remains in the residue. Results of the residue analysis by XRD show the formation of a new crystalline structure when oxalic acid is used. In experiments with other carboxylic acids such as formic and citric acids, no significant changes in the recovery are observed.
The results of a leaching kinetics study of low-grade zinc silicate ore with sulfuric acid are presented. Effect of ore particle size, reaction temperature, and acid concentration on zinc dissolution rate were determined. The results obtained show that leaching of about 94% of zinc is achieved using −200+270 mesh ore particle size at a reaction temperature of 70°C for 180 min reaction time with 10% sulfuric acid concentration. The solid:liquid ratio was maintained constant at 1:20 g/ml. Leaching kinetics indicate that diffusion through the product layer is the rate controlling process during the reaction. The activation energy was determined to be about 3.2 kcal/mol, which is characteristic for a diffusion-controlled process.
This paper presents the results of laboratory scale experiments carried out at CVRD Centre of Technology on the sulphation of Carajás manganese ore using the classical method of pyrometallurgical reduction/ leaching with sulphuric acid. In addition, the removal from impurities of the resulting manganese sulphate solutions was studied by means of jarosite and sulphide precipitation.The results obtained provide preliminary data for the utilization of Carajás ore by the chemical industry, and indicate that this ore is a suitable raw material for the manufacture of manganous sulphate and other manganese containing compounds.
A Pyrolusite (MnO2) ore of industrial interest has been treated by an acid leaching process (H2SO4) with sucrose (C12H24O11) as reducing substance. The aim of the present work has been the preliminary analysis of the leaching process, considering the main factors of the process. The experimental runs have been carried out at different temperatures (50–90°C), acid concentrations (0.1–1 M), reducing substance concentrations (10–40 g/L) and mineral concentrations (5–10% w/v). In some cases, the Analysis of Variance technique (Factorial Experiments) has been used in order to determine the main effects and the cross-interactions of the above parameters. Furthermore, the possible stoichiometry of the reactions has been proposed and experimentally verified. In the experimental runs at 90°C with 10% (w/v) of mineral concentration (size distribution <75 μm) and 20 g/L of sucrose concentration an extraction yield of 73% was obtained after 5 minutes of treatment, and 95% after 30 minutes. Experimental runs using molasse and starch were carried out in order to check the use of the agro-industrial waste material in the leaching process. The measured yield and the extraction rates show the potential application of the process for the manganese recovery from ores of industrial interest.
The aim of this review is to enquire into the development of processes and plants for the recycling of spent alkaline-manganese batteries.This product, which is classified as toxic and noxious because of its content of heavy metals, especially mercury, is now being collected and sent for treatment.Though the problem is only a very recent one, many patents and some plants utilising pyrometallurgical or hydrometallurgical processes have been built in this period.
Of the various mechanical metal recycling techniques employed in electronic scrap processing, air table separation, magnetic separation and eddy current separation technolo gies have proved to be the most commercially successful. In addition, it is very important, even indispensable, that, prior to the physical processing of electronic scrap, selective dis mantling and identification (if necessary) be employed. It is, however, recognized that problems such as process optimiza tion and organics handling remain and that in-depth charac terization of electronic scrap will be essential in this context.
The cathode of spent Zn-MnO2 primary batteries is made up of mainly Mn3O4 and α-MnO2. Energy dispersive X-ray analysis of the cathode surface also shows the presence of zinc from the anode and chloride from the electrolyte. Manganese was recovered by precipitation, electrodeposition and anodization. X-ray diffraction measurements confirmed that the Mn3O4 material was recycled by chemical precipitation. The charge efficiency by electrodeposition was 85% at 25.0mAcm−2. In the current density range studied, the potential/current density plots follow a Tafel-like relation. In the anodic process, the material oxidizes at the electrode/solution interface and precipitates to the bottom of the cell. Only a fraction corresponding to 20% of the charge density is deposited onto the electrode. This happens because Mn2+ oxidizes to Mn3+, which then suffers disproportionation.
A hydrometallurgical route is proposed in this paper for the selective separation of zinc and manganese from spent alkaline batteries. The recycling route comprises the following steps: (1) batteries dismantling to separate the spent batteries dust from other components (iron scraps, plastic and paper), (2) grinding of the batteries dust to produce a black homogeneous powder, (3) leaching of the powder in two sequential steps, “neutral leaching with water” to separate potassium and produce a KOH solution, followed by an “acidic leaching with sulphuric acid” to remove zinc and manganese from the powder, and (4) selective precipitation of zinc and manganese using the KOH solution (pH around 11) produced in the neutral leaching step. For the acidic leaching step, two alternative routes have been investigated (selective leaching of zinc and total leaching) with regard to the following operational variables: temperature, time, sulphuric acid concentration, hydrogen peroxide concentration and solid/liquid ratio. The results obtained in this study have shown that the proposed route is technically simple, versatile and provides efficient separation of zinc and manganese.
The household battery recycling procedures presently in progress in Switzerland are illustrated. Particular attention is devoted to the description of the country's organizations for providing an efficient battery disposal plan. The financial aspects of this plan are also outlined.
Purpose
This paper aims to present a review carried out under DEFRA‐funded project WRT208, describing: the composition of WEEE, current treatment technologies, emerging technologies and research.
Design/methodology/approach
This paper summarises the output from the first part of the project. It provides information on the composition of WEEE and an extensive survey of technologies relevant to materials recycling from WEEE. A series of further papers will be published from this research project.
Findings
WEEE has been identified as one of the fastest growing sources of waste in the EU, and is estimated to be increasing by 16‐28 per cent every five years. Within each sector a complex set of heterogeneous secondary wastes is created. Although treatment requirements are complicated, the sources from any one sector possess many common characteristics. However, there exist huge variations in the nature of electronic wastes between sectors, and treatment regimes appropriate for one cannot be readily transferred to another.
Research limitations/implications
A very large number of treatment technologies are available, both established and emerging, that singly and in combination could address the specific needs of each sector. However, no single set of treatment methods can be applied universally.
Originality/value
This paper is the first part of work leading to the development of technical strategies and methodologies for reprocessing WEEE into primary and secondary products, and where possible the recovery of higher added‐value components and materials.
The electrochemical reduction of gold thiosulfate has been studied and compared to the reduction of gold cyanide. Gold thiosulfate is a potential replacement for gold cyanide in electro and electroless plating baths. Gold thiosulfate has a more positive reduction potential than gold cyanide and eliminates the use of cyanide. The standard heterogeneous rate constant, transfer coefficient, and diffusion coefficient for gold thiosulfate reduction were found to be 1.58 >< 1O cm/s, 0.23 and 7 x 10 cm2/s, respectively. The effect of sulfite as an additive to gold thiosulfate solutions was examined.
The recovery of vanadium from heavy oil fly ash having a high carbon content was performed using a four-step process consisting of a preliminary burning in order to reduce the carbonaceous fraction, followed by an acid leaching and an oxidative precipitation of vanadium pentoxide. The preliminary burning was conducted in the temperature range 650 to 1150 °C, below the initial deformation temperature (IDT) of the fly ash. The temperature of the preliminary burning step was revealed to be a significant parameter. Above 950 °C various phenomena (fusion, volatilisation of V, formation of V–Ni refractory compounds) occurred that adversely affected the recovery of vanadium. The burning temperature of 850 °C was found to be the best as a result of the trade-off between the overall vanadium recovery yield (83%) and the V2O5 weight percentage in the precipitate (84.8%).
This work concerns a three-step process for the recovery of vanadium from heavy oil and Orimulsion combustion fly ashes. This consisted of acid leaching, oxidation and precipitation of the vanadium pentoxide, followed by washing of the precipitate. Preliminary tests were conducted to investigate the effect of some operating parameters for the various steps of the process. After these preliminary tests, the recovery of vanadium from the fly ash samples was performed on a laboratory scale and the overall yield of the process was determined. By washing the precipitate, it was possible to reduce the concentration of the impurities and to allow its use for the production of ferrovanadium alloys.
Fly ash samples were collected from the flue lines of two different oil-fired power plants and analyzed by a variety of analytical procedures designed to determine the V cations extractable from the samples. Both VOâ/sup +/ and VO/sup 2 +/ were shown to be present in the samples. The V(V) cation, VOâ/sup +/, was the principal species extracted from these samples.