High-value Metals Research Articles

Selective recovery of manganese from spent ternary lithium-ion batteries for efficient catalytic oxidation of VOCs: Unveiling the mechanism of activity Enhancement in recycled catalysts

With the widespread application of ternary lithium-ion batteries (TLBs) in various fields, the disposal of spent TLBs has become a globally recognized issue. This study proposes a novel method for reutilizing metal resources from TLBs. Through selective oxidation, manganese in a leaching solution of TLBs was converted into MnO2 with α, γ, and δ crystal phases (referred to as T-MnO2) for catalytic oxidation of volatile organic compounds (VOCs), while efficiently separating manganese from high-value metals such as nickel, cobalt, and lithium, achieving a manganese recovery rate of 99.99%. Compared to similar MnO2 prepared from pure materials, T-MnO2 exhibited superior degradation performance for toluene and chlorobenzene, with T90 decreasing by around 30 °C. The acidic synthesis environment provided by the leaching solution and the doping of trace metals altered the physicochemical properties of T-MnO2, such as increased specific surface area, elevated surface manganese valence, and improved redox performance and oxygen vacancy properties, enhancing its catalytic oxidation capacity. Furthermore, the degradation pathway of toluene on T-γ-MnO2 was inferred using thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) and in-situ DRIFTs. This study provides a novel approach for recycling spent TLBs and treating VOCs catalytically.

Al Impurity Upcycled High-Voltage Cathodes from Spent LiCoO2 Batteries.

Al impurity is among the most likely components to enter the spent lithium-ion battery (LIB) cathode powder due to the strong adhesion between the cathode material and the Al current collector. However, high-value metal elements tend to be lost during the deep removal of Al impurities to obtain high-purity metal salt products in the conventional hydrometallurgical process. In this work, the harmful Al impurity is designed as a beneficial ingredient to upcycle high-voltage LiCoO2 by incorporating robust Al-O covalent bonds into the bulk of the cathode assisted with Ti modification. Benefiting from the strong Al-O and Ti-O bonds in the bulk, the irreversible phase transitions of the upcycled R-LCO-AT have been significantly suppressed at high voltages, as revealed by in situ XRD. Moreover, a Li+-conductive Li2TiO3 protective layer is constructed on the surface of R-LCO-AT by pinning slow-diffusion Ti on the grain boundaries, resulting in improved Li+ diffusion kinetics and restrained interface side reactions. Consequently, the cycle stability and rate performance of R-LCO-AT were significantly enhanced at a high cutoff voltage of 4.6 V, with a discharge capacity of 189.5 mAhg-1 at 1 C and capacity retention of 92.9% over 100 cycles at 4.6 V. This study utilizes the detrimental impurity element to upcycle high-voltage LCO cathodes through an elaborate bulk/surface structural design, offering a strategy for the high-value utilization of spent LIBs.

Comprehensive recovery of valuable metals from spent LiCoO2 cathode material by a method of NH4HSO4 roasting- (NH₄)₂S leaching

With the retirement of rechargeable lithium-ion batteries (LIBs) entering peak period, the recycling of LiCoO2 has become a hot topic. The spent LiCoO2 batteries are rich in carcinogenic metal Co and high-value metal Li, so they are needed to be recovered in time before causing serious environmental pollution and resource waste. Thus, a clean and efficient process is proposed for the comprehensive recovery of Li, Co, and Mn from the spent LiCoO2 cathode material. It is an integrated pyro-hydrometallurgical process, mainly consisting of sulfation roasting with NH4HSO4 and selective sulfurizing leaching with (NH4)2S solution. Using low melting point ammonium salt as roasting auxiliary, 99.7 %, 99.1 %, and 99.8 % of Li, Co, and Mn in the spent LiCoO2 powder can be converted into sulfate when roasting under 400 ℃ for 75 min. Then 99.5 % of Li in the sulfation roasting product can be selectively leached with an aqueous (NH4)2S solution, which is also a precipitator for Co, Mn, and impurity Al. In addition, 96.4 % of Co and 96.0 % of Mn in the sulfurized precipitate can be separated with impurity elements Al and C via oxidation roasting–water leaching process. Compared to traditional recycling, this method can achieve a higher Li leaching rate at a low roasting temperature, and the recovery of Co and Mn can be realized without adding any acid/base reagents or impurity cations. More importantly, the circulation of NH3/NH4+ and S element in the recycling system has been taken into account, making it an environmental-friendly and economical process. In this study, the sulfation reduction roasting and selective sulfurizing leaching mechanisms were both revealed in details, and the behavior of the valuable elements was also elucidated.

Coupled physicochemical dual-crosslinking Ti3C2Tx composite aerogels for the selective adsorption of gallium ions in acid fly ash leaching

Herein, in order to extract Ga3+ from acid fly ash leaching, we propose a functionalized Ti3C2Tx-based MXene composite aerogel adsorbent for Ga3+ adsorption. The prepared physicochemical dual-crosslinking network aerogel MPHG-40 possesses good Ga3+ adsorption performance (132.52 mg g−1) at the pH of 3 and Ga3+ initial concentration of 50 mg L−1 within 6 h. After five adsorption-desorption cycles, the material shows good mass retention and a 95.65 % retention of its initial adsorption capacity, compared to most reported adsorbents. The optimized adsorbent realized good selective adsorption of Ga3+ against Cu2+, Zn2+, Fe3+, and Al3+ in a simulated acid fly ash leaching with the selective coefficient of 8.63, 96.10, 4.49, and 28.30, respectively. The adsorption may comply with a combined mechanism of physical adsorption, electrostatic interactions, ion-exchange mechanism, and ligand chelation, dominated by chemical adsorption, as identified by theoretical calculations based on density functional theory and experimental data. The three-dimensional solid adsorbent constructed in this study provides a new strategy for selective adsorption of Ga3+, making it possible to be applied to solid waste utilization of fly ash.

Valorization of battery manufacturing wastewater: Recovery of high-value metal ions through reaction-enhanced membrane cascade

Leveraging the latent value within battery manufacturing wastewater holds considerable potential for promoting the sustainability of the water-energy nexus. This study presents an efficient method for recovering transition metal ions (Ni2+, Co2+, Cu2+, and Cd2+) from highly saline battery wastewater (Na+, Li+, K+, or Mg2+). Our approach involves the effective utilization of a reaction-enhanced membrane cascade (REMC), comprising a meticulously orchestrated series of selective complexation-decomplexation steps involving polyethyleneimine (PEI) and various transition metal ions. This strategic intervention effectively segregates transition metal ions from salt ions during the fractionation process using an ultrafiltration membrane in a diafiltration process, overcoming osmotic pressure limitations. The ensuing concentration step via nanofiltration achieves an impressive 99 % yield and an extraordinary 215-fold concentration of transition metal ions (>99.8 % purity). The proposed method was validated with 16 different ion pairs to demonstrate its versatility, offering a pragmatic pathway for recycling various transition metal ions from industrial wastewater.

Harnessing carboxymethyl cellulose and Moringa oleifera seed husks for sustainable treatment of a multi-metal real waste

This study aimed to evaluate effective treatment strategies for laboratory waste with an initial pH of 1.0, containing Cr6+, Mn2+, Co2+, Fe3+, Ni2+, Cu2+, Zn2+, Sr2+, Hg2+, and Pb2+ ions, focusing on flocculation, precipitation, and adsorption techniques. The study utilized microparticles derived from Moringa oleifera seed husks (MS), cryogels of carboxymethyl cellulose (CMC), and hybrid cryogels combining CMC and MS (CMC-MS25 and CMC-MS50) as adsorbents. The optimal strategy involved raising the pH to 7 using NH4OH, leading to the partial precipitation of metal ions. The remaining supernatant was then passed through columns packed with the aforementioned adsorbents. Utilizing CMC-MS25 and CMC-MS50 adsorbents resulted in the simultaneous removal of over 90% of the targeted metal ions. The adsorption of Cu2+ ions onto the adsorbents was facilitated by electrostatic interactions between Cu2+ ions and carboxylate groups, as well as Cu–OH chelation, as confirmed by X-ray photoelectron spectroscopy. Under optimized conditions, the fixed-bed column adsorption capacity was determined as 88.2 mg g−1. The CMC-MS25 adsorbents proved reusable at least 5 times, with the recovered Cu2+ ions potentially suitable for other processes. The scalability and feasibility of producing these novel adsorbents suggest a promising, cost-effective solution for treating complex matrices and recovering high-value metals, as copper.

High Lift Value Metal Pipeline Detection Model Based on Metal Magnetic Memory 3-D Differential Method

High Lift Value Metal Pipeline Detection Model Based on Metal Magnetic Memory 3-D Differential Method

Tuning Reactive Crystallization Pathways for Integrated CO2 Capture, Conversion, and Storage via Mineralization.

ConspectusAchieving carbon neutrality requires realizing scalable advances in energy- and material-efficient pathways to capture, convert, store, and remove anthropogenic CO2 emission in air and flue gas while cogenerating multiple high-value products. To this end, earth-abundant Ca- and Mg-bearing alkaline resources can be harnessed to cogenerate Ca- and Mg-hydroxide, silica, H2, O2, and a leachate bearing high-value metals in an electrochemical approach with the in situ generation of a pH gradient, which is a significant departure from existing pH-swing-based approaches. To accelerate CO2 capture and mineralization, CO2 in dilute sources is captured using solvents to produce CO2-loaded solvents. CO2-loaded solvents are reacted Ca- and Mg-bearing hydroxides to produce Ca- and Mg-carbonates while regenerating the solvents. These carbonates can be used as a temporary or permanent store of CO2 emissions. When carbonates are used as a temporary store of CO2 emissions, electrochemical sorbent regeneration pathways can be harnessed to produce high-purity CO2 while regenerating Ca- and Mg-hydroxide and coproducing H2 and O2. Figure 1 is a schematic representation of this integrated approach.Tuning the molecular-scale and nanoscale interactions underlying these reactive crystallization mechanisms for carbon transformations is crucial for achieving kinetic, chemical, and morphological controls over these pathways. To this end, the feasibility of (i) crystallizing Ca- and Mg-hydroxide during the electrochemical desilication of earth-abundant alkaline industrial residues, (ii) accelerating the conversion of Ca- and Mg-carbonates for temporary or permanent carbon storage by harnessing regenerable solvents, and (iii) regenerating Ca- and Mg-hydroxide while coproducing high-purity CO2, O2, and H2 electrochemically is established.Evidence of the fractionation of heterogeneous slag to coproduce silica, Ca- and Mg-hydroxide, and a leachate bearing metals during electrochemical desilication provides the basis for further tuning the physicochemical parameters to improve the energy and material efficiency of these pathways. To address the slow kinetics of CO2 capture and mineralization starting from ultradilute emissions, reactive capture pathways that harness solvents such as Na-glycinate are shown to be effective. The extents of carbon mineralization of Ca(OH)2 and Mg(OH)2 are 97% and 78% using CO2-loaded Na-glycinate upon reacting for 3 h at 90 °C. During the regeneration of Ca- and Mg-hydroxide and high-purity CO2 from carbonate sources, charge efficiencies of as high as 95% were observed for the dissolution of MgCO3 and CaCO3 while stirring at 100 rpm. Higher yields of Mg(OH)2 are observed compared to that for Ca(OH)2 during sorbent regeneration due to the lower solubility of Mg(OH)2. These findings provide the scientific basis for further tuning these reactive crystallization pathways for closing material and carbon cycles to advance a sustainable climate, energy, and environmental future.

Maintaining a proper droplet transfer state in electron beam directed energy deposition via absorbed current-sensed control

Electron beam directed energy deposition (EB-DED) holds immense promise for the fabrication of large, intricate, and high-value metal components. However, with the synchronized nature of material feeding and melting, EB-DED introduces substantial challenges to the stability of the process. This affects both part consistency and repeatability. The droplet transfer process has a crucial part in shaping the stability of EB-DED, with the maintenance of the liquid bridge transfer assuming critical importance in ensuring optimal forming quality. Consequently, we present a cutting-edge closed-loop control system built with absorbed current as a solution to this conundrum. This system harnesses absorbed current signals as the sensory source for droplet transfer states. The droplet transfer state serves as the control objective and the droplet transfer distance acts as the regulated variable. We performed a series of experiments, that corroborated the efficacy of this control system in preserving the desired liquid bridge transfer across diverse scenarios while providing a comprehensive elucidation of its operational principles. By capitalizing on the electron products engendered during the forming process, our control system enabled convenient and reliable monitoring and control of droplet transfer states. The system revealed substantial potential in upholding a well-preserved droplet transfer mode, with significant ramifications for enhancing part consistency and repeatability within EB-DED.

Selective separation of metals from waste printed circuit boards using supergravity-assisted liquation technology

Waste printed circuit boards (WPCBs) are the most crucial components of electronic waste，containing high-value metals that are attractive secondary sources and main recycling targets. This study proposed a combined method of supergravity technology and liquation technology to separate metals from WPCBs. Fe-rich, Cu–Zn and Cu–Sn phases were gradually precipitated and separated in supergravity fields. Two key parameters of separation temperature and gravity coefficient were investigated under different conditions. The optimum temperature was 1100 °C for separating Fe-rich alloy, and 800 °C for separating Cu–Zn and Cu–Sn alloy. Moreover, controlling the gravity coefficient at 600 in this study was deemed the most appropriate and energy-efficient. Under the optimum conditions, the mass fractions of Fe, (Cu + Zn), and (Cu + Sn) in Fe-rich, Cu–Zn, and Cu–Sn alloy reached 81.8 wt%, 95.0 wt%, and 89.9 wt%, respectively. A potential industrial apparatus for the novel method was also proposed. The results demonstrate that the proposed supergravity-assisted liquation method is a promising and optimized approach for selectively separating metals from WPCBs.

A new hyperaccumulator plant (Spergularia rubra) for the decontamination of mine tailings through electrokinetic-assisted phytoextraction

The screening of new effective metal hyperaccumulators is essential for the development of profitable phytoremediation projects in highly degraded environments such as mining areas. The goal of this research was to analyze the phytoextraction potential of the native plant Spergularia rubra to decontaminate and eventually recover metals (phytomining) from the mine tailings (belonging to an abandoned Pb/Zn Spanish mine) in which it grows spontaneously. To do so, the ability of this plant species to accumulate metals was evaluated both under natural conditions and through simple and electrokinetically assisted phytoextraction tests using alternating current and different combinations of voltage gradient (1/2 V cm−1) and application time (6/12 h per day). The complete duration of the greenhouse trial was 64 days, although alternating current was applied only during the last 14 days. The results obtained demonstrated the exceptional effectiveness of S. rubra for metal hyperaccumulation and growth without affecting toxicity in highly contaminated mining waste. Zn was the metal accumulated to a higher extent in the shoots, reaching concentrations up to 17,800 mg kg−1; Pb was mainly accumulated in the roots reaching a maximum concentration of 8709 mg kg−1. Cu and Cd were accumulated to a lesser extent but the bioconcentration factors were much >1. It has been proved that S. rubra is a hyperaccumulator species for Zn and Cd both in natural and greenhouse conditions and, very probably, Pb in wild conditions. The application of AC current did not significantly increase metal concentrations in plant tissues but it was able to increase the aerial biomass of S. rubra by 49.8 %. As a result, the phytoextraction yields of all metals were significantly improved as compared to wild conditions (up to 86 % for Zn). It could open new expectations about the economic viability of recovering high-value metals from mine tailings.

Synergetic treatment of waste tantalum capacitors and polyvinyl chloride by subcritical water: Tantalum recovery, benzoic acid production and dechlorination

The rapid upgrading of electronic products led to the generation of a great deal of waste tantalum capacitors (WTCs). The recovery of WTCs is of great interest due to the high-value metal tantalum and resin materials. However, it is difficult to separate/recover the materials from WTCs because of the special structure and composition. Polyvinyl chloride (PVC) waste with high level of chlorine could result in severe corrosion and emission of chlorinated pollutants in the conventional disposal process. In this study, a synergetic and high-efficiency treatment of WTCs and PVC by subcritical water (SubCW) process was developed based on the interaction of the two kinds of wastes. The interaction between WTCs and PVC in SubCW could significantly reduce the treatment temperature and shorten the reaction time for recovering high-purity metal tantalum from WTCs, and it could also markedly improve the dechlorination efficiency (DE) of PVC. The optimized conditions for the synergetic treatment of WTCs and PVC were 325 ℃, 30 min, solid-to-liquid ratio of 1:5 g/mL, and PVC-to-WTCs ratio of 6:1 g/g. The resin conversion efficiency (RCE) of WTCs and the DE of PVC could reach 100% and 97.39% under the optimized conditions. The HCl released from PVC in SubCW could significantly promote the acid-catalytic hydrolysis of resin materials in WTCs and resulted in the production of abundant phenol/phenol derivates. In turn, hydroxyl functional group of phenol/phenol derivates could enhance the dechlorination of PVC by promoting the hydroxyl substitution reaction pathway. High level of benzoic acid (72.52%) could be obtained from the interaction between the decomposition products of WTCs and PVC by radical and oxidation reactions. The SubCW synergetic process developed in this study provided a high-efficiency and low-energy strategy for metal tantalum recovery, benzoic acid production, and dechlorination from WTCs and PVC wastes.

From waste to wealth: Valuable metals recovered from waste tungsten leaching residue by a smelting reduction process using CaO-Fe capture agent

Tungsten leaching residue (W-residue), a hazardous waste generated from the industrial recovery of the spent tungsten carbides, poses a threat to the environment. The W-residue contains high grades of SiO2 and TiO2 oxides, and low grades of high-value metal oxides such as WO3, CoO, Ta2O5, and Nb2O5. Herein, a smelting reduction process was proposed to effectively recover the high-value metals from the W-residue and obtained a medium-entropy carbide (MEC) composite. During the smelting process, the valuable metals were recovered as alloy consisting of (Fe, Co)-rich silicide, (Fe, Cr, W)-rich silicide, and (W, Ta, Nb, Ti)C, respectively. The addition of flux CaO lowered the liquidus temperature of the molten slag, and effective alloy-slag phase separation was achieved by adding Fe as a metal collector to capture the alloy droplets entrapped in the slag. Under the optimal conditions, the total recovery rate reached 86.8%. Moreover, the obtained (W, Ta, Nb, Ti)C as MEC exhibited a Vickers hardness of over 19 GPa and can be used as a wear-resistant alloy. This study proposed a strategy for extracting high-value metals from hazardous tungsten residue, which could complement existing recycling processes towards a closed-loop process in the tungsten industry.

Influence of Wire Feed Speed and Torch Speed on the Mechanical Properties of Wire Arc Additively Manufactured Stainless Steel

Abstract Wire arc additive manufacturing (WAAM) enables 3D printing of large high-value metal components. However, integrating WAAM into production lines requires a critical understanding of the influence of process parameters on the resulting material characteristics. As such, this research investigates the relationship between WAAM wire feed speed (WFS) and torch speed (TS) on the resulting mechanical characteristics of 316LSi thick parts (2.5 cm (0.98 in.)). The experimental procedure is informed by a training matrix that allows parametric analysis of WFS and TS on the ultimate tensile strength (σult), yield strength (σy), elastic modulus (E), failure strain (εf), hardness (HV0.5), and dimensional accuracy (Da) of the printed samples. The research found that WAAM-processed 316LSi parts feature isotropic material properties despite variations in WFS and TS. The surrogate model developed in this study offers five significant polynomial models capable of accurately predicting the influence of WAAM process parameters on σult, σy, εf, E, and Da. The research found TS to be the most significant WAAM process parameter in comparison to WFS for σult and εf. On the contrary, σy, E, and Da were found to be primarily driven by WFS as opposed to TS. Overall, the paper for the first time presents an accurate surrogate model to predict the mechanical characteristics of WAAM 316LSi thick parts informed by wire feed speed and torch speed. The study demonstrates that the mechanical properties of WAAM-processed steel are primarily influenced by the underlying process parameters offering significant potential for tunable performance.

A novel method for recovering valuable metals from spent lithium-ion batteries inspired by the mineral characteristics of natural spodumene

Based on the unique crystal structure characteristics of natural spodumene (LiAlSi2O6) with six coordination of Li at the M2 position and monoclinic crystal system, an innovative approach is developed for the simultaneous recovery of Co, Ni, and Cu, while selectively enriching Li into the slag. The slag system was designed and controlled according to thermodynamic simulations and calculations to provide the theoretical basis for subsequent experiments. The effects of the ratio of Al2O3 to SiO2, temperature, and ratio of raw material to oxidizer addition on metal recovery were systematically investigated. The results showed that Li, Co, Ni, and Cu recovery efficiencies could exceed 99%, while Li was concentrated in the slag with a high grade of Li2O (6.0–9.0 wt%) under the experimental conditions, which is about 1.0–1.6 times that of the commercially available spodumene concentrate (Li2O, 5.5 wt%). By sulfation roasting-leaching of this lithium-rich slag, a leaching efficiency of Li can be achieved to 93%. This study provides valuable insights into shortening the recycling process of spent lithium-ion batteries and increasing the comprehensive utilization rate of high-value metals.

Extraction of High-value Metals from Boron Waste by Bioleaching Using Aspergillus niger

Extraction of High-value Metals from Boron Waste by Bioleaching Using Aspergillus niger

Processing of automotive shredder residues: Economic evaluation of a process for energy and high-value metals recovery

Challenges in recycling heterogeneous waste remain untapped. Automotive shredder residue is one such heterogenous waste generated after processing End-of-Life Vehicles, making it difficult to process. There are two impediments to the recycling of ASR. One is the heterogeneity of the ASR (as received), and the other is not knowing what constituents to be extracted from the ASR. The ability of the thermochemical process to transform waste into beneficial products is well known. The objective of this work is based on a techno-economic evaluation of the recovery of energy and high-value metals from Automotive Shredder Residue. The equipment sizing and fabrication cost of each piece used in this process are calculated based on laboratory experiments. An integrated techno-economic study for processing heterogeneous waste ASR has not been studied in the literature previously. The economic evaluation was carried out assuming a plant life of 25 years. In addition, the plant's revenue was generated by the obtained products, and the payback period for energy and metal recovery was found to be 3 years respectively. The capital cost and operating cost for the ASR recycling plant with a combined approach of recovering energy and metals have been estimated from grass root stage. The outcome of this study confirms that ASR recycling has potential value for secondary resources and the process is economically viable. The resource recovery from ASR is an environmentally friendly technology where the maximum utilization rate is raised, along with energy saving and environmental protection by reduction of ASR waste in landfill.

Ultra-selective chelating membranes for recycling of cobalt from lithium-ion spent battery effluents by electrodialysis

The recovery of valuable resources from spent effluents is critical to ensure sustainable growth and reduce commodity shortages at global levels. Spent batteries are largely untapped resources containing multiple high-value metal ions that may be harnest and resued indefinitely to develop a circular battery economy. Challenges however lay with the cost of purification and recovery strategies and the limited selectivity of existing processes. This work presents the development of selective cation exchange membranes suitable for the selective recovery of cobalt from mixtures of lithium, cobalt, and nickel from spent battery effluents. Efficient cation exchange membranes were generated by modifying poly(vinyl chloride) films with ethylene diamine followed by grafting of 5-chloro-8-hydroxyquinoline (5C8Q) chelating agents and two synthesis routes were compared including surface and bulk grafting and the membrane separation properties were benchmarked against CIMS Neosepta. Besides being stable across a pH range between 2 and 8, relevant to spent battery lixiviat, the surface grafted membranes exhibited the lowest energy of sorption in comparison to bulk membranes, which was ten times lower than that of the commercial CIMS Neosepta reference membranes. The transfer of ions from model single salt solutions across the surface grafted membranes allowed for over 60 % of cobalt recovery within 1 h, while nickel and lithium were transferred only up to 18 % and 0.2 %, respectively. In addition, the electrodialysis-based separation of multi-component solutions remained very cost-effective with cobalt ion removal amounts up to 58 %, leading to Co/Li separation factors as high as 247. This novel chelating agent strategy opens avenues for the development of highly efficient and selective membrane materials, which are able to operate in extreme pH environments and supporting ultra-selective ionic transfer.

Recovery and Recycling of Valuable Metals from Spent Lithium-Ion Batteries: A Comprehensive Review and Analysis

The recycling of spent lithium-ion batteries (Li-ion Batteries) has drawn a lot of interest in recent years in response to the rising demand for the corresponding high-value metals and materials and the mounting concern emanating from the detrimental environmental effects imposed by the conventional disposal of solid battery waste. Numerous studies have been conducted on the topic of recycling used Li-ion batteries to produce either battery materials or specific chemical, metal or metal-based compounds. Physical pre-treatment is typically used to separate waste materials into various streams, facilitating the effective recovery of components in subsequent processing. In order to further prepare the recovered materials or compounds by applying the principles of materials chemistry and engineering, a metallurgical process is then utilized to extract and isolate pure metals or separate contaminants from a particular waste stream. In this review, the current state of spent Li-ion battery recycling is outlined, reviewed, and analyzed in the context of the entire recycling process, with a particular emphasis on hydrometallurgy; however, electrometallurgy and pyrometallurgy are also comprehensively reviewed. In addition to the comprehensive review of various hydrometallurgical processes, including alkaline leaching, acidic leaching, solvent (liquid-liquid) extraction, and chemical precipitation, a critical analysis of the current obstacles to process optimization during Li-ion battery recycling is also conducted. Moreover, the energy-intensive nature of discussed recycling process routes is also assessed and addressed. This study is anticipated to offer recommendations for enhancing wasted Li-ion battery recycling, and the field can be further explored for commercialization.

Industrial Recycling Process of Batteries for EVs

The growing number of decarbonization standards in the transportation sector has resulted in an increase in demand for electric cars. Renewable energy sources have the ability to bring the fossil fuel age to an end. Electrochemical storage devices, particularly lithium-ion batteries, are critical for this transition’s success. This is owing to a combination of favorable characteristics such as high energy density and minimal self-discharge. Given the environmental degradation caused by hazardous wastes and the scarcity of some resources, recycling used lithium-ion batteries has significant economic and practical importance. Many efforts have been undertaken in recent years to recover cathode materials (such as high-value metals like cobalt, nickel, and lithium). Regrettably, the regeneration of lower-value-added anode materials (mostly graphite) has received little attention. However, given the widespread use of carbon-based materials and the higher concentration of lithium in the anode than in the environment, anode recycling has gotten a lot of attention. As a result, this article provides the most recent research progress in the recovery of graphite anode materials from spent lithium ion batteries, analyzing the strengths and weaknesses of various recovery routes such as direct physical recovery, heat treatment recovery, hydrometallurgy recovery, heat treatment-hydrometallurgy recovery, extraction, and electrochemical methods from the perspectives of energy, environment, and economy; additionally, the reuse of recycled anode mats is discussed. Finally, the problems and future possibilities of anode recycling are discussed. To enable the green recycling of wasted lithium ion batteries, a low energy-consuming and ecologically friendly solution should be investigated.