Article

A review of technologies for the recovery of metals from spent alkaline and zinc–carbon batteries

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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.

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... 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]. ...
Article
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.
... 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]. ...
Article
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.
... The most relevant battery recycling processes and selected representative companies in the EU for alkaline battery recycling are mainly based on pyrometallurgical treatment or possess a stage with thermal pre-treatment. These pyrometallurgical techniques consist basically on the selective volatilization of metals at elevated temperature followed by condensation (Sayilgan et al., 2009). These methods are often seen as less expensive routes, capable of high metal recovery with a rapid reaction rate without the necessity of complex pre-treatment process; they allow the separation of materials in the form of molten metal or gases from other products that can be high value byproducts. ...
... After the collection of spent batteries and before their chemical treatment, some mechanical/physical pre-treatments are required. These may include shredding or cut-crashing, thermal procedures, separation of ferrous metal from inert compounds (paper, plastic, ferrous and non-ferrous scraps) by the use of magnets as well as powder sieving (Sayilgan et al., 2009). Subsequently, hydromettalurgical processes may be applied, usually in small scale plants, which involves leaching, separation and metal recovery steps. ...
Article
This review paper aims to present and analyse data from the most recent literature (between 2007 and 2019) published on the topic of manganese (Mn) and zinc (Zn) recovery from zinc-based spent batteries through hydrometallurgical methods. In a first attempt, a detailed comparative assessment of the metals leaching performance (as well as the experimental variables that influence its performance) reported in the various studies with strong acid or bases, potentially supplemented by complexing or reducing agents, as well as the reactions involved, are reviewed and discussed. All data point out that the use of a reductant is needed to fully solubilize Mn from spent batteries during the leaching process. Comparison of the data seem to indicate that most reductants have similar performance and, therefore, the choice of a reductant should be focused on low cost or even waste materials. In a second attempt, the separative processes mostly described in the literature to recover Mn and Zn from leachates are reviewed emphasizing the strengths and weaknesses of each technique. Solvent extraction is the most widely tested process for this aim. A thorough comparison of existing data indicates that, in general, neutral extractants have higher potential for selective separation of Zn and Mn. Furthermore, although chemical precipitation is a simple process, low pure final metal hydroxide products are expected to be achieved when alkaline precipitation is implemented comparatively to the Mn oxidative precipitation where Mn can be recovered selectively as a solid of manganese (IV) oxide.
... Furthermore, these batteries have a certain lifetime, and the increase in volume of spent batteries over the last few years requires an innovative recycling process. Findings from research into metal recovery in recent years indicate the importance of recycling spent batteries [1][2][3][4][5][6][7][8]. In Canada, Call2recycle collected more than 2.5 kt of batteries for recycling in 2017 and 2.7 kt in 2018, of which 78% consisted of alkaline and Zn-C batteries [9]. ...
... To obtain a pure manganese solution, zinc precipitation was achieved by adding Na 2 S (2 SMR of Na 2 S at pH [4][5]. Under these conditions, up to 100% of zinc was precipitated (Table 5) and the obtained ZnS could be added to the first leaching stage for PLS-1 rich in Zn. ...
Article
Full-text available
An innovative, efficient, and economically viable process for the recycling of spent alkaline batteries is presented herein. The developed process allows for the selective recovery of Zn and Mn metals present in alkaline batteries. The hydrometallurgical process consists of a physical pre-treatment step for separating out the metal powder containing Zn and Mn, followed by a chemical treatment step for the recovery of these metals. Sulfuric acid was used for the first leaching process to dissolve Zn(II) and Mn(II) into the leachate. After purification, Mn was recovered in the form of MnO2, and Zn in its metal form. Furthermore, during the second sulfuric acid leaching, Na2S2O5 was added for the conversion of Mn(IV) to Mn(II) (soluble in the leachate), allowing Mn to be recovered as MnCO3. Masses of 162 kg of Zn metal and 215 kg of Mn (both in the form of MnO2 and MnCO3) were recovered from one ton of spent alkaline batteries. The direct operating costs (chemicals, labor operation, utilities, energy) and indirect costs (amortization, interest payment) required for a plant treating 8 tons of spent batteries per day was calculated to be $CAD 726 and $CAD 534 per ton, respectively, while the total revenue from the sale of the metals was calculated at $CAD 1359.6 per ton of spent batteries. The development of this type of cost-effective industrial process is necessary for a circular economy, as it contributes to addressing environment- and energy-related issues, and creates opportunities for the economic utilization of metals.
... Glucose is a low cost and non-hazardous chemical and was first proposed for Mn reducing leaching of pyrolusite ores [48,49] and zinc manganese dioxide alkaline battery [50]. It was discovered that the leaching solution contained high concentrations of formic acid along with mono-carboxylic poly-hydroxyl acids like glyceric acid and glycolic acids, suggesting that glucose was oxidized. ...
... H 2 SO 4 Leach Flowsheet[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50]. ...
Article
With the increasing market share of lithium-ion battery in the secondary battery market and their applications in electric vehicles, the recycling of the spent batteries has become necessary. The number of spent lithium-ion batteries grows daily, which presents a unique business opportunity of recovering and recycling valuable metals from the spent lithium-ion cathode materials. Various metals including cobalt, manganese, nickel, aluminum, and lithium can be extracted from these materials through leaching with chemicals such as hydrochloric acid (HCl), nitric acid (HNO3), sulfuric acid (H2SO4), oxalate (H2C2O2), DL-malic acid (C4H5O6), citric acid (C6H8O7), ascorbic acid (C6H8O6), phosphoric acid (H3PO4) or acidithiobacillus ferrooxidans. This paper provides a comprehensive review on the available hydrometallurgical technologies for recycling spent lithium-ion cathode materials. The recycling processes, challenges and perspectives reported to date and recycling companies in the market are summarized. To accelerate the development of battery recycling technology toward commercialization, some potential research directions are also proposed in this paper.
... 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]. ...
... 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]. ...
... 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. ...
Article
Full-text available
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.
... It is shown in Fig. 4 that the mechanical process such as gravity, magnetic, and pneumatic separations can separate scrap plastics and iron containers from cathodic materials. However, battery dismantling is not mandatory in the pyrometallurgy process (Sayilgan et al. 2009). In case of Li-ion battery, electrochemical discharging requires to avoid short circuiting of Li-contained materials (Chabhadiya et al. 2019). ...
Chapter
Renewable energy, by means of energy capture, storage, and transmission, is able to fulfil the catastrophic energy demand worldwide but requires suitable storage devises. Rechargeable batteries are prominent to do so. However, based on the capability of energy storage, Ni-Cd, Pb-acid, and Li-ion batteries are the most important and remained in wider use among others. Therefore, a large number of batteries is being spent after completion of their life span, and this needed to be handled in proper manner. The landfill disposal may cause severe environmental problems like soil, ground, and water pollution with the hazardous and toxic contents therein (like Cd, Ni, Co, KCl). Additionally, such kind of disposal is a huge loss of resources as to the criticality and strategic importance of these metals due to their crustal abundance and geopolitical scenario. Efficient recycling of spent batteries can lead toward the sustainable solution of this problem via conservation of primary ores by recovery of metals, waste minimization, and recycling. Recycling of spent battery is in trend and has been a global topic for environmentalists and metallurgists. Several research works have been done that clearly indicate the economic and environmental interests in this area. Therefore, we attempt, in this chapter, to investigate and discuss the recycling processes for the extraction, separation, and recovery of metals from not only a technological perspective but also the related environmental issues.
... Comparing with pyrometallurgical techniques, hydrometallurgy processes are highly lucrative in terms of low cost operation, possible recovery of leachants and reduced air pollution level (Sethurajan et al., 2019;Sayilgan et al., 2009;Innocenzi et al., 2014). In hydrometallurgical process to recover the rare earth in the powder mix coming from the waste resources belongs to the decomposition and leaching step. ...
Article
Present day rising necessity for rare earth elements (REE) is of great interest for its recovery through processing various waste materials concerning both economic and environmental benefits. The present study investigates the recovery potential of yttrium from fluorescent lamp waste using a hydrometallurgical process. Leaching of metals from the waste was studied by applying acids viz. hydrochloric acid (HCl), nitric acid (HNO3) and sulfuric acid (H2SO4). Influence of various factors (solid:liquid ratio, reaction temperature, reaction time, and acid concentration) were conducted by full factorial design for the recovery of yttrium. Experimental variables such as decomposition, leaching and the oxide preparation were studied and the mechanisms responsible during the progress in each step was systematically investigated. The optimal experimental conditions attained with 40% solid/liquid ratio, at 45oC in 0.5 h at 150 rpm, with 3N H2SO4 concentration. Whereas, HCl and HNO3 leachants showed poor performance. Leaching process conducted in this study were best suited to ‘ash diffusion control dense constant size-spherical particles model’, which means that the diffusion process through the ash is the rate regulatory step in the leaching process. With increase in the concentration of oxalic acid as precipitating agent, a reduction in the nuclear induction period resulted indicating a higher sedimentation rate and shorter equilibration time. In addition, crystal nucleation rate and crystal growth rate, showed that the reaction velocity of the crystal nucleation ‘p’ is 2.88 and the crystal growth degree and value increases with the increase in the concentration of oxalic acid (n: 0.3437 ∼ 0.4872). The precipitation rate was improved with the rise in temperature (from 25oC to 45oC) while the sedimentation rate was found negligible above 45oC. This detailed study methodology can be considered as a feasible process thus creating a possibility to treat fluorescent waste lamp powders for various industrial applications.
... Large-scale applications require low-cost, stable electrode active materials. Lithium manganese oxide, LiMn 2 O 4 (LMO), is a suitable cathode material for large-scale LIB applications because Mn is found abundantly in nature in the form of minerals as well as in spent alkaline-manganese batteries [2,3] and has a stable spinel-type crystal structure. However, the LMO cathode suffers from cycling performance degradation at high temperatures (>50°C) [4][5][6]. ...
Article
Full-text available
The cyclability of LiMn2O4 (LMO), a spinel cathode used in Li-ion batteries (LIBs), at high temperatures (>50°C) should be improved. In this study, we use an olivine-type LiMnPO4 (LMP) cathode with a composite structure as the surface material to improve the cyclability of LMO. The fabrication strategy includes mechanical coating of the LMO core with shell precursor particles and their subsequent transformation into LMP rod particles via hydrothermal vapor conversion. The core-shell precursor particles (composing NH4MnPO4·H2O (AmMP) plates) are successfully converted into LMO@LMP composite particles with a rod-like surface layer. The composite cathode fabricated with 7 mass% AmMP exhibits improved capacity retention of 72% after 30 cycles at 60°C, while that of the uncoated LMO cathode decreases to 63%. Further structural arrangement of the surface particles can lead to the development of a suitable cathode material for large-scale applications of LIBs.
... This indicates that the sulfur is oxidized by the ferric sulfate species, and that the sulfate ion allows the formation of zinc sulfate as aqueous species. Ferrous iron oxidizes to ferric iron in the presence of oxygen, according to Equation (7). However, comparing the energies values between Equations (7) and (8), its shows that the oxidation reaction is more thermodynamically possible in the presence of sulphuric acid rather than just H + . ...
Article
Full-text available
The present work reports the direct leaching of zinc from a sphalerite concentrate in acid media. Lab-scale and pilot-scale experiments were conducted in atmospheric-pressure and low-pressure reactors, respectively. Leaching of zinc and precipitation of iron was achieved in the same stage using different reagents like Fe 3+ , O 2 , O 3 , and Fe 2+ (which is continuously oxidized in the leaching solution by H 2 O 2 and O 2). The highest percentage of zinc extraction (96%) was obtained in pilot-scale experiments using H 2 SO 4 , Fe 2+ , and O 2. Experimental results were compared with those of other researchers to provide a better understanding of the factors influencing the dissolution of zinc. In the first instance, it was determined from analysis of variance that leaching time and the use of an oxidant agent (O 2 or O 3) were the most influential factors during the direct leaching of zinc from the sphalerite concentrate. Kinetic models were also evaluated to determine the rate-limiting step of the sphalerite leaching; it was concluded that the type of the sulfur layer formed in the residue (porous or non-porous) depends on the type of the oxidant used in the leaching media, which determines the dissolution kinetics of zinc.
... Due to the large volume and widespread dispersion of battery waste, safe landfill disposal involving adequate operation and maintenance of liners, leachate collection, and detection of toxic waste or leaks can be costly (Sayilgan et al., 2009). Exposure to toxins such as cadmium have been reported to cause brain damage and impair skeletal development (Duruibe, Ogwuegbu, Egwurugwu, et al., 2007). ...
Article
Growing concern about the degradation of the environment and public health has called into question the use of conventional household batteries that are consumed and then typically discarded. Because most conventional batteries are not recycled, they end up in landfills where they decompose, potentially leaching harmful chemicals into the surrounding soil. Bio‐based batteries, which are made from agricultural by‐products, have been designed to help meet the need for household batteries while using sustainable, safe technology. This research examines the links between consumer willingness‐to‐pay (WTP) for bio‐based batteries and consumer characteristics and preferences for certain product attributes and environmentally‐friendly practices. We designed a nationwide survey and analyzed the survey data using the dichotomous‐choice contingent valuation method. The results show an increase in the estimated WTP in the Midwest and South in response to an information treatment about bio‐based batteries. Overall, U.S. consumers concerned about green production and recycling practices are willing to pay a premium for bio‐based batteries. Our results provide essential information for quantitatively assessing the potential market impact of bio‐based batteries, for developing effective management and marketing strategies to reach various consumer groups, and for efficiently establishing sustainable policies and regulations.
... Zinc is primarily associated with sulfide i.e. sphalerite (ZnS)-a zinc ore, and it is basically extracted by pyro and hydrometallurgical based methods; where 80% of zinc is being produced worldwide via hydrometallurgical route (Cole and Sole, 2002;Sahu et al., 2004). Zinc produced via such routes finds various application in galvanization of alloy products, automobiles, construction, batteries like Zn-Mn batteries, household appliances and so forth (Deep and de Carvalho, 2008;Sayilgan et al., 2009). This is corroborated by the demand in galvanizing sector (~50%), die-casting (17%), brass and bronze (17%) and other chemicals and miscellaneous products as per report of International Lead and Zinc study group (Hern� andez-Betancur et al., 2019;Khunte, 2018). ...
... As a consequence, more electronic devices produce more pollution and hazardous wastes [1], demanding cleaner manufacturing processes and initiatives elsewhere [2]. Consequently, the battery waste has also significantly increased [3]. Alkaline batteries occupy most of the primary battery market, particularly in developed countries where nonrechargeable batteries are the most used due mainly to its low costs and relatively good performance [4]. ...
Article
A new multifunctional and sustainable composite material manufactured from a vinyl-acrylic resin mixed with primary battery waste (BW) powders in 5, 10, 15, and 20 wt% contents. The waste was obtained from a recycling company as a byproduct of the primary batteries grinding process (alkaline and zinc carbon batteries), which was mainly composed by graphite, manganese oxide, and zinc oxide. The characterization was conducted by scanning electronic microscopy, density, hardness, compression strength, x-ray diffraction and FTIR tests. Dimension stability tests were conducted in order to determine the shrinkage percentage. Sensors were built in three different electrode geometries, in order to evaluate the piezoresistivity of the developed formulations. It was found in this research that the compound with the highest BW content showed the highest modulus of elasticity, corresponding to 2.28 MPa; the shrinkage for the specimen with 0%BW was 68.37% and the specimens with BW content (5, 10, 15, and 20%BW) the shrinkage was 15.97%. The maximum conductivity was reached by the compound with 10% BW and was approximately 0.01 S/m. These results showed a promising waste derived material able to use in electronics, inexpensive, and with a very positive impact for the environment. A statistical analysis of the piezoresistivity variables of each sensor was performed using RStudio software. For resistivity, the variable that affects the sensor the most is the amount of battery residue; while for the final resistance and sensitivity, the most important variable is the geometry of the sensor. The percolation threshold is nearly to 5 wt% BW.
... This is due to more stringent regulations and costs, environmental protection, raw materials and preservation issues. This is applicable also for other battery components such as plastic, paper, and steel (Sayilgan et al., 2009). ...
Article
Fast industrialization has increased the demand for heavy metals, on the other hand, high-grade ore natural reserves are belittling. Therefore, alternative sources of heavy metals need to be investigated. Massive amounts of industrial wastes are being generated annually. The majority is sent to landfills or to incinerators, which eventually poses environmental challenges such as ecological contamination and health hazards to living beings. Such industrial wastes contain hazardous elements of various metals (Au, Ag, Ni, Mo, Co, Cu, Zn, and Cr), whose improper disposal leads to adverse effects to human being and the environment. As a result, methods for industrial waste management such as reuse, remanufacturing, and recycling have received much attention due to the fact that they improve cost effectiveness over time and enable the metal recovery businesses to thrive profitably. The present study provides a state of art review on the current technologies existing for the recovery of precious metals from industrial wastes streams to analyse the sustainability. Among the wastes, spent petroleum catalysts, medical waste, electronic scraps, battery wastes, metal finishing industry waste, and fly ash are some of the largest industrially-generated wastes. Various metal recovery processes involve physical, chemical, and thermal characteristics of waste streams and target metals for separation and extraction. The current challenges of pyrometallurgy, modification on the hydrometallurgy, physical and chemical methods and other advanced technologies are presented in this review. The hydrometallurgical method, which involves dissolving and leaching, is a proven and successful process for recovering metals from various raw materials. Several other recovery methods have been proposed and are currently being implemented; the problem is that most of them are only successful in retrieving certain metals based on specific properties of industrial waste. The recovered metal solutions are further concentrated and purified using adsorption, cementation, chemical precipitation, ion exchange, membrane filtration and ion flotation techniques, which can also be applied to other liquid waste streams. The recovery method only makes sense if the recovery cost is much less than the value of the precious metal. The limitations placed on waste disposal and stringent environmental legislation require environmentally-friendly metal recovery technologies. This review paper provides critical information that enables researchers to identify a proper method for metal recovery from different industrial wastes, and also it benefits researchers and stakeholders in determining research directions and making waste management-related decisions.
... 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). ...
Chapter
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.
... 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]. ...
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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
... 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). ...
Article
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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. ...
Article
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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). ...
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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.
... These disposed dry cell batteries disintegrate with time and the chemicals and metals inside the batteries leach to the environment. Their toxicity, abundance and permanence in the environment results in severe impact on nature and poses grievous health consequences [2]. Also, the limited storage availability of landfills/dumpsites and increased expenses of disposal necessitates recycling of these batteries. ...
Patent
The present invention demonstrates a novel synthesis approach for graphene from waste battery electrodes.
... 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. ...
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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. ...
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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
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In this work, inorganic pigments were synthesized by solid state reaction, from the incorporation of components of exhausted alkaline batteries. For this, after disassembling the batteries, the components were subjected to water leaching, milling and heat treatment at high temperatures with an addition of 33% (in mol) commercial or recovered from own alkaline batteries anodes zinc oxide. The obtained pigments were characterized by X-ray diffractometry, scanning electron microscopy, laser diffraction particle size, and UV-Vis diffuse reflectance spectroscopy. It was concluded that incorporation of the components of batteries generally yielded brown pigments with a structure of the spinel type ZnMn2O4. SEM and particle size distribution analyses show that the addition of ZnO leads to a reduction in average grain size of the powders. The pigments when applied to color ceramic enamels, polymers and paints show good performance in the coloring of these products, with potential for commercial application.
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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.
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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.
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Magnetic ferrite/biochar composites are a kind of promising adsorbents due to their high adsorption efficiency and facile magnetic separation; however, their synthesis is associated with high cost and secondary environmental impacts. In this study, a novel Mn–Zn ferrite/biochar composite (MZF-BC) is synthesized via a green two-step biocheaching and hydrothermal method using waste batteries and pine sawdust. Characterization results indicate that the introduced Mn–Zn ferrite particles are successfully embedded and coated on biochar (BC), and synthesized MZF-BC50 with 50% BC content exhibits best performance with a specific surface area of 138.5 m² g⁻¹, the saturation magnetization of 27.5 emu g⁻¹ and CEC value of 53.2 mmol 100 g⁻¹. The maximum adsorption capacity of Pb²⁺ is 99.5 mg g⁻¹ based on the Langmuir sorption isotherm study at 298 K, and pseudo-second-order model accurately describes the adsorption process. Regeneration test suggests that MZF-BC50 can be efficiently reused for 6 cycles. In addition, it exhibits a good selective Pb²⁺ and Cd²⁺ removal performance in lead-acid battery wastewater. The results illustrate that this newly developed material has low cost and rapid remediation of Pb²⁺ as good application potential.
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This research investigates the extraction behavior of copper and zinc from the sulfate leachate of a porcelain stone tailings sample with Chemorex CP-150 and D2EHPA in detail. The findings demonstrated that Chemorex had greater ability and selectivity in the extraction of copper, while D2EHPA was better in the extraction of zinc. 97.88% copper and 78.2% zinc were extracted, respectively, with Chemorex and D2EHPA within 10 min contact time at an 1:1 aqueous/organic ratio, 10% (v/v) extractant concentration, and ambient temperature. The appropriate solution pH levels for Chemorex and D2EHPA were found to be 2.5 and 2, respectively. Also, a McCabe–Thiele diagram was drawn and one single-step extraction for copper and a two-stage process for zinc were needed to achieve the highest extraction efficiency. Additionally, the mechanism study indicated the association of ~ 1.5 and 1 mol of Chemorex CP-150 and D2EHPA for the extraction of one mole of Cu and Zn from the leach solution. Moreover, thermodynamic parameters, including ΔH, ΔG and ΔS were found to be 65.29 kJ/mol, 9.83 kJ/mol, and 186.14 J/mol K for copper and − 18.71 kJ/mol, 17.80 kJ/mol, and − 122.53 J/mol K for zinc, respectively, indicating that the extraction process was endothermic for copper and exothermic for zinc. The effect of contact time, pH, and extractants concentration on the extraction efficiency of Cu and Zn by Chemorex CP-150 and D2EHPA and also the number moles required for extractants
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By 2025, 2 million metric tons of batteries must be recycled. Among these batteries, the spent Zinc-Manganese batteries poses a serious threat to environment due to toxic heavy metals. This metals are toxic but at same time vital for various industrial applications. This metals are generally recovered by physical-chemical process which are highly energy intensive and polluting. An eco-friendly recycling process has to be explored to tackle such issue. The bioleaching is one such eco-friendly recycling method. The objective of this work is to optimize the process parameters of bioleaching method, so as to make this process commercially viable. The optimization of this process is done through statistical based automated neural network intelligent optimization approach. The formulated models were inline with the complex behaviour of bioleaching process. The training and validation performance of the models were near to 1. The parametric, global sensitivity and interaction analysis was undertaken for understanding the relationship between different parameters and its affect on the metal yield. The optimum values of process parameters were determined for maximizing the metal yield.
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Fine-grained fraction (<1.25 mm) of industrial zinc ash was characterized in terms of chemical and phase compositions as well as leaching behaviour in hydrochloric acid solutions. Waste product contained about 55% Zn, 14% Cl, and less than 0.4% of other metals (Fe, Pb, Al, etc.). It was a mixture of metallic zinc, simonkolleite, zinc oxide, and zinc hydroxide chloride. Dissolution of metals from the zinc ash was determined depending on the solid-to-liquid ratio (1:80-1:20), acid concentration (0.23-2.0 M), and temperature (20-60ºC). The best results (almost 100% zinc recovery) were obtained for 2M HCl at 20ºC, S:L ratio 1:20, and leaching time 30 min. The final solutions were contaminated mainly by iron and lead ions (both below 0.15 g/L). Further treatment of the solution to obtain metallic zinc or zinc chloride was also proposed.
Article
A single oxidative leaching process was developed for simultaneous enhancement of dissolution of nickel and precipitation of lanthanum by using Na2S2O8 in sulfuric acid solution from a heat-treated mixture of batteries containing 50 wt.% alkaline batteries, 25 wt.% Ni-MH batteries, and 25 wt.% Ni-Cd batteries. The effect of leaching parameters was investigated, including the concentrations of sulfuric acid, Na2S2O8, and H2O2, the temperature, and the leaching time. The results show that almost all metals such as zinc, manganese, and cadmium are dissolved by 2 M sulfuric acid, but the leaching efficiency of nickel is 86.8%. However, in a leaching process using Na2S2O8, the leaching efficiency of Ni is enhanced while lanthanum is selectively precipitated in the form of NaLa(SO4)2·H2O at the same time, and this result is supported by XRD, ICP, and SEM analysis. Under the optimum conditions of 2 M H2SO4, 10 vol.% H2O2, 10 vol.% 1 M Na2S2O8, and 95 ℃, 97.8% of the nickel is leached while 98.8% of the lanthanum is selectively precipitated. This study shows that the separation and purification stages can be simplified to recover La and valuable metals.
Chapter
In the present chapter, the author has elaborated how manganese‐based material for Zn batteries will exhibit extensive properties for the future use, along with the electrochemical properties like voltage, capacity, and efficiency and number of cycles for the manganese‐based Zn‐batteries. By studying all these properties, we have decided best performance shown in manganese‐based Zn batteries. Zinc‐manganese dioxide batteries are the first ever commercial dry batteries, designed based on the technology of the wet Leclanche cell, and are the cheapest and most widely available dry cell. This battery is still very popular. The manganese‐based battery is one of the best‐selling batteries and it has widely dominated the market worldwide.
Chapter
The growing demand for electric energy storage has prompted many researchers to pursue advanced replacement batteries. Zn‐based batteries have attracted widespread attention as a viable alternative to the lithium‐ion batteries that surround the market. The zinc‐air batteries have been taken into consideration because of its low cost, high‐energy density, safer battery technology, and environmental friendliness. These rechargeable batteries are very important because of their usability in portable electronic devices, grid management, and electrical vehicles. However, due to their durability, cycle life, and efficiency, these batteries have not yet been widely used in practical applicability. Zinc particles are commonly used as anode material in primary zinc air batteries. One of the challenges in zinc‐air batteries is zinc anode, which has a significant effect on the performance of these batteries. In this chapter, the challenges and problems facing zinc anodes of electrically rechargeable zinc‐air batteries are discussed. Different solutions to overcome these problems are discussed and the effects of some modifiers on Zn‐air batteries performance are investigated. Another purpose of this chapter is to provide adequate information to design a new and improved zinc anode in order to increase the performance and stability of this anode, consequently the increase of the battery energy efficiency and its lifetime.
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Concerns over considerable solid waste production, increasing environmental pollution, and the energy crisis have assigned a high value to solid waste recycling. Solid waste can be recycled as a potential substitute for some chemical substances. Additionally, a promising strategy is the conversion of solid waste into heterogeneous catalysts for use in environmental remediation and renewable energy production. Hence, this article aims to provide a state-of-the-art review of recent developments in solid waste-derived heterogeneous catalysts (e.g., supported and Cu-, Co-, Mn-, Fe-, and Ca-based) for organic contaminant removal and biodiesel production. First, the types and characteristics of solid waste that are suitable to be processed into catalysts are summarized. This is followed by a brief description of the recycling technologies and processes of solid waste-derived environmentally friendly catalysts. Next, the applications of these new valuable heterogeneous catalysts in organic pollutant removal and biodiesel production are emphasized. Finally, some future research directions are proposed.
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Nowadays, humankind is in urgent need of energy generation and storage systems. The supercapacitor is one of the essential types of storage systems. The high cost of obtaining capacitor electrodes is the reason behind the researchers’ attempts to find low-cost sources. The need for the development of efficient energy storage systems is paramount in meeting the world’s future energy targets, especially when the energy costs are on the increase in addition to the escalating demand. Energy storage technologies can improve efficiencies in supply systems by storing the energy when it is in excess, and then release it timely. Batteries are slowly becoming obsolete due to their poor cyclability (limited to a few thousand) and long charge time (tens of minutes) in comparison to supercapacitors. On the other hand, supercapacitors have a long lifetime and fast charging times. Nowadays, the research focuses on advanced suitable electrode materials that directly reflect in supercapacitor technology enhancement. The researchers have prepared a variety of single components and hybrid electrodes by recycling various environmental wastes. The recycled materials include metal oxides (MnO2, Co3O4, etc.), carbon materials (carbon nanosphere, porous carbon nanoparticles, activated carbon), and hybrid materials (MnO2/graphene, CaO/AC). The obtained materials exhibited interesting structural and morphological properties as well as excellent energy storage behavior. The recycling technique provides a unique alternative cheap way for getting supercapacitor electrode materials, as well as it helps to maintain a clean environment.
Chapter
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.
Article
A sustainable and effective sulfuric acid-based process with the combination of facile acid leaching and electrowinning has been developed for the recovery of valuable elements from spent silver oxide batteries. Results suggest that the dissolution of elementary Ag was markedly promoted by the presence of MnO2 in the spent silver oxide batteries. Also, H2O2 was added to support an improved Mn and Ag extraction after 240 min of leaching. In the leaching step, 97% of silver and over 99% of Mn and Zn could be extracted under the optimum conditions: 1 mol/L H2SO4, a leaching temperature of 70 °C, an S/L ratio of 50 g/L, addition of 3 v/v % H2O2 at 240 min, and a total leaching time of 270 min. Ultra-pure silver (Ag w/w % ≥ 99.98%) was further recovered from the pregnant leaching solution (PLS) by potentiostatic electrowinning. Under the optimum deposition potential of −0.10 V and after 4 h of electrowinning, the silver recovery reached 98.5% with a high energy efficiency of 98.7%. Simultaneously, 5.6% Mn was recovered on the anode in the form of MnO2. Overall, these promising results suggest feasibility in the recycling of silver oxide batteries in sulfuric acid media.
Article
The utilization of mildly acidic electrolyte and corresponding Mn salt pairing unlocked a path toward highly rechargeable Zn-MnO2 batteries, but long-term feasibility of these cathode-preserving strategy under practical conditions is never verified. In this study, in-situ MnO2 electrodeposition occurring in the battery recharging process is discovered to be a side reaction that substantially nullifies the practicality of the strategy. Particularly, it is identified to be responsible for irreversibly converting the electrolyte Mn ions to electrochemically passive species and triggering battery performance deterioration. These newfound recognitions lead to the formulation of a kinetic inhibition strategy, which is executed through an unconventional cathode electrode design. Specifically, graphite nanosheets with limited surface defects are incorporated into MnO2 electrodes to hinder the rate determining Mn adsorption process and thus effectively suppress the electrodeposition reaction. The resulting thin film binder-free MnO2 electrodes achieve near-full one-electron capacity reversibly for over 600 cycles, with an average columbic efficiency of ∼99.8%. Overall, this study reveals the importance of suppressing MnO2 electrodeposition in Zn-MnO2 batteries and provides a contrasting view on key factors that dictate the stability of the system.
Article
A spent alkaline battery-based (SB) catalyst was prepared from the black mass of a spent alkaline battery to determine the potential of recycling spent alkaline batteries as catalysts for the total oxidation of hydrocarbons. Five different acids (H2SO4, HNO3, C2H2O4, HCl, and H3PO4) were used to examine the effect of acid treatment on catalytic activity during catalyst preparation. Hexane, benzene, toluene, and o-xylene (HBTX) were adopted as the VOCs for experiments. The properties of the prepared catalysts were studied using ICP/OES, BET, XRD, ATR/FTIR, TGA, SEM, and H2-TPR analyses. The results showed that acid treatment significantly influenced the activity of the SB (400) catalyst, with the type of acid also found to greatly influence the activity of the catalyst. The order of activity according to the type of acid was H2SO4 > HNO3 > C2H2O4 > HCl > H3PO4 > none. Good performance of an acid-treated SB catalyst was associated with high concentrations of manganese and iron and a large BET surface area. In addition, the sequence in which the TPR peaks appeared at low temperatures according to each acid treatment was consistent with that of catalyst activity.
Article
While alkaline battery is the one that dominates portable battery market in Australia, its recycling rate is far from sufficient. In the current work, small-scale carbothermic process to recover high value zinc/zinc oxide (Zn/ZnO) powder from spent alkaline black mass is studied. The study involved experimental investigation, process modelling that includes thermodynamics and mass and energy balance calculations, and techno-economic analyses. Continuous and batch-type process plants; as well as adoption of solar energy were considered in the study. It was found that Zn/ZnO recovery process is economically viable at the current Australian annual black mass production (200 tonnes/year) with a minimum annual income and IRR value over 20 years plant lifetime of AU$509,742 and 19.1%, respectively. A minimum capacity of 100 tonnes/year is expected to ensure that the process is economically favourable. The application of concentrated solar energy, however, enables the batch process to be carried out at a much lower capacity of 15 tonnes/year. The results of this study can be extended to better inform the feasibility of a small-scale process in countries other than Australia.
Article
Spent alkaline and zinc-carbon batteries contain valuable elements (notably, Zn and Mn), which need to be recovered to keep a circular economy. In this study, the black mass materials from those spent batteries are pyrometallurgically treated via a series of process steps in a pilot-scale KALDO furnace to produce an Mn–Zn product, a ZnO product, and an MnO (manganese monoxide) product, toward applications of Mn–Zn micronutrient fertilizer, zinc metal, and manganese alloy, respectively. After an oxidative roasting step, an Mn–Zn product, containing 43% Mn, 22% Zn, and negligible amounts of toxic elements (notably, Cd, Hg, and Pb), could be produced, being suitable for the micronutrient fertilizer application. After a reductive roasting step, a ZnO product and an MnO product are produced. The attained ZnO product, containing up to 84.6% ZnO, is suitable for zinc metal production when the leaching steps are taken to remove most of the Cl and F in the product. The attained MnO product, containing up to 91.7% MnO, is of premium quality for manganese alloy production, preferably for SiMn alloy production due to its low phosphorus content. The proposed application scenarios could substantially improve the recovery efficiency of those spent batteries.
Article
Among the currently available processes, iron precipitation as hematite from hydrometallurgical process solutions is the most suitable from an environmental point of view. The crystallization and dissolution of ferrous sulfate play an essential role in the hematite process. In this work, the effects of the Zn²⁺ concentration, temperature and oxygen partial pressure on the ferrous ion concentration, solution pH, and the composition of filter residues and crystallization sediments were studied. The influence of the dissolution behavior of ferrous sulfate on the hematite process was explained based on crystallization theory. The results indicated that the ferrous ion concentration in the solution showed a “wave-like” change in the presence of Zn²⁺ due to the common ion effect and the isomorphism effect. The sulfur content in filter residues increased as the concentration of SO4²⁻ was increased by the addition of zinc sulfate and due to the increasing concentration of ferrous ions. Additionally, the maximum variation was obtained for the Fe content decreased from 11.52% to 7.3% and Zn content increased from 20.86% to 24.54% in the sediments.
Chapter
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Wastewater treatment has been drawing more and more attention due to increasing water pollution. The most common sources of water pollution are heavy metals, dyes, plastics, and foods from industries. Animal, agriculture, and farm wastes are other important causes of water pollution. Several adsorbents have been tested for wastewater treatment. Among these, activated carbon (AC) is the best and the most effective adsorbent for a specific class of pollutants because of its abundant starting materials availability, high surface area, surface reactivity, adsorption efficiency, and porosity structure. Although commercial AC has outstanding potential in the industry of water treatment, the usage is limited because of the high cost. The high initial cost and expensive regeneration of AC motivate the search for low cost, disposable ACs from conventional wastes materials to remove dyes, volatile organic compounds, heavy metals, and organic pollutants. The main goal of this chapter is to compare and list the advantages and disadvantages and methods of AC preparation from wastes materials as adsorbents and their application in water treatment to remove pollutants.
Article
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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.
Article
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.
Article
Manganese oxide catalysts have been synthesized from the used batteries via hydrometallurgical method and effect of hydrometallurgical parameters such as the effect of acid type (H2SO4, HNO3, HCl), acid concentration (0.5, 1, 1.5, 2 %v/v) and powder to acid ratio (1/50, 1/60, 1/70, 1/80) were in detail investigated. The physico-chemical properties of as-prepared catalysts were characterized by FT-IR, XRD, FESEM, EDX, BET, TEM, and TPR-H2 analysis. The activity of as-prepared catalysts were investigated towards the oxidation of benzene, toluene, and xylene (BTX) in a plasma-catalytic process. The results show that benzene and toluene conversion were almost constant in the range of 97–98% in case of various acid types, acid concentrations and solid to liquid ratios. However, the xylene conversion were varied in case of different hydrometallurgical factors. The highest xylene conversion was obtained in the presence of MnS0.5–60, which was prepared using H2SO4 with concentration of 0.5%v/v and solid to liquid ratio of 1/60. The effect of the input voltage and BTX flow rate on the BTX conversion was also investigated using MnS0.5–60 catalyst in detail.
Conference Paper
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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.
Conference Paper
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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).
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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).
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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.
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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.
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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.
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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.
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Conference Paper
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.
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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.
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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.
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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.
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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).
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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%).
Article
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.
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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.
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Fly ashes resulting from the combustion of fuel containing high concentrations of vanadium that can be slightly removed by water and more efficiently by alkaline or acid solutions. This uncontrolled release can contaminate water sources and requires appropriate storage of fly ashes. This study investigated the possibility of cleaning the ashes by leaching the material and recovering vanadium by solvent extraction (for metal concentration solutions higher than 200 mg V L-1) using several amine extractants (Primene JM-T, Amberlite LA-2, Alamine 336, and Alamine 304), a quaternary ammonium salt (Aliquat 336), and by a sorption process (for low-metal concentration solutions) using chitosan. Extraction and stripping were investigated with liquid extractants and showed that Aliquat 336 was the best of these extractants. However, since Aliquat 336 exhibits a greater difficulty at stripping, secondary or tertiary amine extractants appear more suited for the extraction process. Vanadium sorption occurs on chitosan through anion exchange with a maximum sorption capacity of 400 to 450 mg V g(-1) at pH 3. The treatment of acid leachates with chitosan does not appear possible, since it requires a pH control to pH 3, which precipitates ferric ions and coprecipitates vanadium. Alternative routes could be the alkaline leaching of fly ashes and a further pH control.
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The extraction of zinc was studied with solvents containing bis (2,4,4-trimethylpentyl)phosphinic acid and its monothio and dithio analogues. Comparative data are presented to illustrate the effect of composition (sulphur substitution) on the extraction and stripping characteristics of the three reagents. Special emphasis is given to the selective separation of zinc from sulphate solutions containing calcium. The effect of aralkyl versus alkyl groups in the molecule is also illustrated and important extractant properties such as hydrolytic stability and aqueous solubility are discussed.