Free Access
Issue
Metall. Res. Technol.
Volume 117, Number 3, 2020
Article Number 302
Number of page(s) 10
DOI https://doi.org/10.1051/metal/2020025
Published online 08 May 2020

© EDP Sciences, 2020

1 Introduction

Lithium-ion batteries (LIBs) find applications in mobile electronic devices and electric vehicles because of favorable characteristics [1]. Technological advancements and increasing consumption of electronic commodities lead to massive accumulation of LIBs [13]. Inadequate disposal of waste LIBs containing toxic and flammable compounds with heavy metals can cause severe environmental and health issues [2,4,5]. Discarded LIBs contain 5–20% cobalt, 5–10% nickel, 5–7% lithium, 5–10% copper, aluminum, iron, 15% organic compounds, and 7% plastics [3]. Lithium, cobalt, and natural graphite are classified as critical metals [6]. The cathode material comprises lithium transition metal oxides such as LiCoO2, LiMn2O4, LiNixMnyCoz, LiNi0.5Mn1.5O4 (LNMO), LiFeO4 deposited on aluminum foil [6,7]. India imports cobalt and lithium because of limited primary production [8]. Discarded batteries comprise Li, Co, Mn, Ni contents, which are significantly higher than in primary ores; therefore, recycling of waste lithium-ion batteries is essential for resource conservation, environmental concerns, and beneficial to the circular economy [5]. Recycling of discarded LIBs involves pyrometallurgical, hydrometallurgical, or a combination of these processes [2,5]. A pyrometallurgical process involves high-temperature reduction smelting (> 1000 °C) of different battery feed. Metallic values (Co, Ni, Cu, and Mn) are recovered in alloy form, whereas Li and Al transfer to the slag fraction [9,10]. Dang et al. [11] used chlorination roasting (800 °C, 60 min) followed by water leaching (60 °C, 30 min) for recovery of lithium from simulated slag of the pyrometallurgical process. Hydrometallurgical processing involves the separation of the active material from the steel case, Al and Cu fraction [12]. Leaching of active material is carried out in inorganic acids (H2SO4, HCl, H3PO4, HNO3), organic acids (citric acid, ascorbic acid, succinic acid, oxalic acid) and reducing agents (H2O2, Na2SO3, NaHSO3, glucose) to recover Co, Mn, and Ni [6,10,13,14] followed by metal extraction through solvent extraction and precipitation route [10,12,15]. Leaching of nickel cobalt manganese cathode material was also reported in ammonical solution (NH4)2CO3, NH4HCO3, (NH4)2SO4 and NH4Cl) with reductant (Na2S2O3 and Na2HPO3) in an autoclave using S/L (solid to liquid) ratio of 1:100, 50 °C, 500 rpm, 30 min [15]. Low energy consumption, higher metal recoveries, multiple steps, expensive reagents, and considerable effluent generation are the main attributes of the hydrometallurgical processes [4,16].

Recently, cobalt, manganese, nickel, and lithium are recovered from the discarded LIBs using reduction roasting with reductants (coke, carbon black, or lignite) in an inert atmosphere (argon or vacuum) with subsequent water and H2SO4 leaching [1721]. Roasting (600 °C, 180 min, argon atmosphere) of cathode material (LiNixCoyMnzO2) with graphite followed by sulfuric acid leaching (85 °C, 60 min, S/L: 1:6, 1.05 times of theoretical acid consumption) is followed to improve metal recovery [5]. The requirements of an inert (vacuum/argon) atmosphere and external reductants, and multiple heating-cooling cycles in the existing thermal processing for recycling LIBs are a bottleneck for process implementation and cost considerations. In our previous work, the carbothermal reduction was carried out on LCO and mixed LCO, LMnO (LiMn2O4) in a muffle furnace in an ambient atmosphere [4,16,22]. Because of the heterogeneous composition of batteries containing Co, Mn, Ni, an effective recycling process needs to recover all metallic values from mixed-phase cathode material. L1 denotes the single-phase cathode material (LCO), and L3 depicts mixed cathode material (LCO, LMnO, LNMO). The main objectives of this work include: (a) reduction behavior of cathode materials (LCO and LCO. LMnO. LNMO) under ambient and inert atmosphere; (b) reductant selection for carbothermal reduction (graphite vs. activated charcoal); (c) product characterization; (d) energy calculation.

2 Materials and methods

Spent LIBs of different mobile phone manufacturers were obtained from a registered recycler and were discharged by soaking in 5 wt.% sodium chloride solution for 24 h to avoid the risk of short circuits. Discharged batteries classified as L1 and L3, where cathode material of L1 contains single-phase LCO, and L3 comprises mixed LCO, LMnO, and LNMO. The batteries were manually dismantled; both electrode sheets were separated and dried for 24 h at room temperature (25 °C) before pulverization in an attritor (IKA A11). Pulverized material was sieved at 53-micron sieve to separate the active material from metals. The fraction above 53-micron size comprises Cu and Al. Homogenized active cathode material and reductant (graphite or activated charcoal) were mixed at a predetermined dosage and reduced in a muffle furnace (ambient atmosphere, Carbolite) and tube furnace (inert atmosphere, Carbolite) at different temperature (600–1000 °C) and time (30–60 min). A refractory grade silica crucible was used for heat treatment experiments. The heating rate was 10 °C/min. Heat-treated product was subjected to distilled water leaching at a solid to liquid ratio of 1:50, 1000 rpm, 10 min, and 25 °C in an overhead stirrer (IKA RW 20). Carbonation of water leach solution was conducted by purging industrial-grade CO2 gas for 30 min at a flow rate of 0.05 L/min. Vacuum filtration and evaporation of leach solution were applied at a temperature of 250 °C on a hot plate for the recovery of lithium carbonate (Li2CO3). For the recovery of Co, Mn, and Ni by magnetic separation, a slurry of water leach residue was prepared using a solid to liquid ratio of 1:80 and subjected to a wet magnetic separator (Eriez) at a magnetic intensity of 1500 Gauss. Homogenized active cathode material (L3) was subjected to hydrometallurgical processing under optimum conditions reported in the literature [23,24]. The leaching was carried out in 4 M sulfuric acid for 120 min at twice the stochiometric dosage of H2O2, 90 °C, 120 min, S/L: 1:8. Alternatively, leaching was carried out in citric acid at 1.5 M, 2 vol % H2O2, 95 °C, 30 min, and S/L: 1:20. The preliminary flowsheet is schematically shown in Figure 1. The yield of the magnetic fraction is computed as:

Analysis of different phases of active material was performed by X-ray diffraction (XRD, Rigaku) at a scanning rate of 2°/min with 2 theta range of 10–100°. XRD analysis of cathode material and graphite is shown in Figure 2a. Morphology and composition analysis was determined using scanning electron microscopy (SEM; Carl Zeiss) and energy dispersive X-ray spectroscopy and inductively coupled plasma mass spectroscopy (ICPMS, ELAN DRC). The morphology study reveals irregular particles in L1 and L3, as displayed in Figures 2b and 2c. The carbon content of graphite was measured as ∼ 84.3% using a carbon-hydrogen nitrogen sulfur (CHNS) analyzer (Vario micro). The lithium content was determined with a flame photometer (Systronic). The composition and key characteristics of L1 and L3 are shown in Table 1. The concentration of Co, Mn, Ni, Li in acid leach solution was determined using ICPMS. The magnetic properties of various fractions were evaluated using a vibrating sample magnetometer (VSM, Quantum PAR 155). The saturation magnetization of different phases is Co: 162.7, CoO: 1.27, Co3O4: 0.9, MnO: 0.1–0.3, Mn3O4: 1–8 and Ni: 57.5 emu/g [2528]. Thermal behavior of cathode, graphite, and charcoal was investigated using thermo-gravimetric analysis (TGA, SII 6300 EXSTAR), at 10 °C/min under air atmosphere. Weight loss up to 1200 °C in L1, L3, graphite, and charcoal were 10, 12.6, 92.9, and ∼ 91%, respectively, as shown in Figure 2d. Weight loss is higher in L3, depicting higher stability of L1. Activated charcoal oxidized faster and at low temperatures compared to graphite [29].

thumbnail Fig. 1

Flowsheet of the experimental procedure used in this work.

thumbnail Fig. 2

(a) XRD analysis of L1, L3, and anode; Morphology, the composition of (b) L1, (c) L3; (d) TG plot in air atmosphere.

Table 1

Characteristics of L1 and L3 cathode materials.

3 Results and discussion

3.1 Thermodynamic assessment

LCO possesses a lamellar structure comprising alternate layers of cobalt and lithium [30]; however, it dissociates to Co3O4, Li2O, and O2 beyond 900 °C. The dissociation of LCO leads to Li2O, CoO, O2 below 937 °C [4,20]. Graphite oxidation occurs because of CO and CO2 formation and depends on the temperature, oxygen content, and is predicted by weight loss [31]. Li2O reacts with CO2 to form Li2CO3, and CoO is reduced to Co with C or CO [20]. LMnO possesses a cubic spinel structure and dissociates in Li2O, Mn3O4, and O2, and Mn3O4 is reduced by C or CO to MnO [19,32,33]. LNMO with spinel structure dissociates to NiO, Li2O, Mn3O4 beyond 600 °C [18,32,34]. Below 1400 °C, MnO cannot be reduced to Mn as per thermodynamic considerations [33]. Hence, LCO, LMnO, LNMO can be reduced by graphite during heat treatment of active cathode material above 600 °C [34]. The overall reaction mechanism and the steps involved in the carbothermic reduction of both cathode materials are summarized in Figure 3. LCO, LMnO, LNMO are present in combined form in the active material, and hence higher reductant dosage is required for reduction.

thumbnail Fig. 3

Proposed reaction mechanism of LCO, LMnO, and LNMO.

3.2 Muffle furnace reduction

The parameters for the process are selected based on TGA results and preliminary experiments, and the effect of temperature (600–1000 °C), time (30, 45, 60 min) and graphite dosage (10–40%) was studied. The reduction was conducted using graphite at a constant temperature (900 °C) and time (45 min). Saturation magnetization increases with increasing graphite dosage up to 30% and further saturates, as shown in Figure 4a. Further, on increasing the reduction time at a fixed temperature (900 °C) and graphite dosage (30%), saturation magnetization, lithium extraction, and weight loss increased, as shown in Figure 4b. The effect of temperature on process responses for both L1 and L3 at fixed graphite dosage (30%) and time (60 min) are shown in Figure 4c. For L3, the weight loss increased with increasing temperature up to 900 °C and saturated beyond 900 °C, while lithium extraction increased up to 900 °C, attaining a maximum value (90%) and decreased with increasing temperature. The saturation magnetization increased significantly with temperature because of the phase transformation of CoO to Co and is in agreement with XRD results. Similar trends were observed for L1; however, saturation magnetization decreased beyond 950 °C because of the re-oxidation of Co and CoO phases to Co3O4. The weight loss increased on increasing the temperature, graphite dosage, and time due to the reduction of oxides (CoO, Mn3O4, NiO) to lower oxide (MnO) and metallic (Co, Ni) phases as confirmed by XRD analysis. Lower weight loss was observed in L1 compared to L3 because of the higher stability of L1 and agrees with TGA results.

Further, the reduction was carried out with charcoal at 885 °C, 30% C, 60 min. The process responses of the reduced product with both reductants are shown in Table 2. Saturation magnetization, lithium extraction, and yield values were relatively higher in the case of graphite, whereas higher weight loss was found for activated charcoal. The morphology and composition of different magnetic fractions are shown in Figures 5a5d. Reduced L3 fraction of both graphite and charcoal consists of Co: 68%, Mn: 21%, Ni: 2.5%, O: 8.5% and Co: 63%, Mn: 13%, Ni: 7%, O: 17% respectively and for L1 magnetic fraction comprises Co: 70%, O: 30% and Co: 68%, O: 32% respectively. The low saturation magnetization of the L1 magnetic fraction is because of the higher CoO content and low ferromagnetic Co phase compared to the L3 magnetic fraction, as revealed by XRD.

thumbnail Fig. 4

(a) Variation of graphite dosage for L3 (900 °C, 45 min); (b) variation of time at 900 °C, 30% C for L3; (c) temperature effect at fixed dosage (30% C), time (60 min) for L1, L3.

Table 2

Process response of different routes at 885 °C, 30% C, 60 min; where G-graphite and C-charcoal.

thumbnail Fig. 5

SEM-EDS of the magnetic fraction at 885 °C, 30%C, 60 min in a muffle furnace for (a) L3-G (b) L3-C, (c) L1-G, (d) L1-C; where G-graphite and C-charcoal.

3.3 Tube furnace reduction

Based on the success in the muffle furnace reduction under ambient conditions (30% graphite dosage and 60 min), the controlled reduction was carried out in the tube furnace. The reduction was carried out at different temperatures (600–1000 °C) in an argon atmosphere (0.05 L/min), and the corresponding temperature effect on process response is shown in Figure 6. For L3, saturation magnetization increased with temperature up to 850 °C, achieving the maximum value of 115 emu/g and decreased beyond 850 °C because of oxidation of Co, CoO to Co3O4. A similar trend was observed for L1, attaining a maximum saturation magnetization of 129 emu/g with the formation of a pure cobalt phase. It was observed that saturation magnetization and yield were relatively higher for L1 magnetic fraction, whereas lithium extraction was higher for L3 magnetic fraction, as shown in Figure 6a. The morphology and composition of the magnetic fraction of L1 and L3 shown in Figures 6b and 6c comprise Co: 94%, O: 6%, and Co: 70%, Mn: 15%, Ni: 4% and O: 11% respectively. Magnetic fractions obtained have higher metallic concentration than feed showing the significant enrichment of metal content.

XRD analysis of magnetic fractions for different routes is shown in Figure 7a. Very similar phases were present in L3 reduced fractions, i.e., Co, CoO, MnO, Mn3O4, and Ni. Metallic Co phase was attained in the inert atmosphere using graphite for L1, whereas, Co, MnO, and Ni were present in L3. XRD analysis of solution crystal reveals almost pure lithium carbonate with minor LiF peak yielding 97% purity, as shown in Figure 7b. XRD analysis reveals that only carbon is present in non-magnetic fraction, and the absence of LCO, LMnO, LNMO indicates the complete dissociation of cathode material. The yield of non-magnetic fraction decreased on increasing temperature and time due to the increased oxidation rate of graphite. The yield of non-magnetic fraction obtained with activated charcoal was relatively lower, depicting a higher oxidation rate of activated charcoal. Graphite is a layered structure with a hexagonal arrangement of atoms within each layer and possesses crystalline nature; whereas, activated charcoal has higher porosity, surface reactivity, and extensive surface area but lacks long-range periodicity [35,36]. The apparent energy of activation of graphite and activated charcoal is similar; however, the graphite and charcoal oxidation rates were different because of different internal surface areas. The rate of oxidation is directly proportional to the surface area. Rate is higher with activated charcoal because the presence of micro-pores results in higher surface area. It is in agreement with the TG result [29].

thumbnail Fig. 6

(a) Effect of temperature on process responses at 30% C, 60 min in a tube furnace with graphite; SEM-EDS of magnetic fractions at 850 °C, 30% C, 60 min of (b) L3, (c) L1.

thumbnail Fig. 7

XRD of (a) magnetic fractions, (b) solution crystal, of L1, L3 at optimum conditions (muffle furnace: 885 °C, 30% C, 60 min; tube furnace: 850 °C, 30% C, 60 min); (G-graphite and C-charcoal).

3.4 Hydrometallurgical processing

Homogenized active cathode material (L3) was also subjected to hydrometallurgical processing under optimum conditions reported in the literature [23,24] and was compared with the results of the present investigation, as shown in Table 3. XRD analysis of phases observed in leach residue of aqua regia, sulfuric acid, and citric acid leaching consists of LCO, LNMO, and LCO, LNMO, Co3O4 respectively showing partial dissociation of cathode material. The overall comparison of different routes in the present study is summarized in Table 4. Cost and energy calculations were conducted for processing of 2 kg batteries in both muffle and tube furnace, as given in Table 5. The energy consumption of reduction of cathode material was ∼ 92.4 and 90 kWh/kg batteries in muffle and tube furnace routes, respectively, and processing cost was higher in the tube furnace because of an inert atmosphere. The overall input cost was ∼ 7.23 and 13.96 $/kg batteries while the product costs are ∼ 23.63, 23.57 $/kg batteries in a muffle furnace, and tube furnace route, respectively providing positive net cash flow.

Table 3

Summary of hydrometallurgical experiments.

Table 4

Overall comparison of different routes followed in this study.

Table 5

Cost and energy calculation of different routes followed.

4 Conclusions

Carbothermic reduction of cathode material (LCO and mix LCO, LMnO, LNMO) using graphite and activated charcoal was investigated in an ambient and inert atmosphere for recovery of Co, Mn, Ni, and Li. Based on cobalt purity, effective reduction of L1 cathode material was observed in the inert atmosphere, whereas for L3, ambient conditions and inert atmosphere yielded similar results. For higher metal recovery (Co, Mn, Ni, Li), the inert atmosphere is better for L1 and ambient atmosphere for L3. Based on the product purity and metal recovery values, graphite was found superior reductant for cathode materials in the ambient atmosphere. The proposed route is encouraging, as the entire battery material can be used. Metal recovery of product comprising Co (95%), Mn (70%), Ni (25%), Li (83%) was higher in muffle furnace route and is a potential raw material for cathode manufacture of LIBs. Overall input costs for metal recovered from L3 were ∼ 7.23, 13.96 $/kg batteries, and product cost is ∼ 23.63, 23.57 $/kg batteries in a muffle, and tube furnace routes respectively, and corresponding energy consumption was 92.4 and 90 kWh/kg batteries. Processing of single-phase LiCoO2 cathode material in an inert atmosphere yielded better product, whereas, mixed cathode material responded better in ambient conditions. Finally, it can be summarized that the carbothermic processing of cathode materials is suitable for the extraction of Co, Li, and Mn from mixed spent batteries.

Acknowledgments

The authors are thankful to the Indian Institute of Technology, Roorkee, India, for providing Faculty Initiation Grant.

References

  1. B. Swain, Recovery and recycling of lithium: A review, Sep. Purif. Technol. 172, 388 (2017) [Google Scholar]
  2. T. Or, S.W. Gourley, K. Kaliyappan, A. Yu, Z. Chen, Recycling of mixed cathode lithium-ion batteries for electric vehicles: Current status and future outlook, Carbon Energy (2020), https://doi.org/10.1002/cey2.29 [Google Scholar]
  3. J. Ordonez, E.J. Gago, A. Girard, Processes and technologies for the recycling and recovery of spent lithium-ion batteries, Renew. Sustain. Energy Rev. 60, 195 (2016) [CrossRef] [Google Scholar]
  4. S. Pindar, N. Dhawan, Carbothermal reduction of spent mobile phones batteries for the recovery of lithium, cobalt, and manganese values, JOM 71, 4483 (2019) [CrossRef] [Google Scholar]
  5. Y. Zhang, W. Wang, Q. Fang, S. Xu, Improved recovery of valuable metals from spent lithium-ion batteries by efficient reduction roasting and facile acid leaching, Waste Manage. 102, 847–855 (2020) [CrossRef] [Google Scholar]
  6. E. Rudnik, J. Knapczyk-Korczak, Preliminary investigations on hydrometallurgical treatment of spent Li-ion batteries, Metall. Res. Technol. 116, 603 (2019), https://doi.org/10.1051/metal/2019008 [CrossRef] [EDP Sciences] [Google Scholar]
  7. H. Liu, G. Zhu, L. Zhang, Q. Qu, M. Shen, H. Zheng, Controllable synthesis of spinel lithium nickel manganese oxide cathode material with enhanced electrochemical performances through a modified oxalate co-precipitation method, J. Power Sources 274, 1180 (2015) [Google Scholar]
  8. Indian Bureau of mines, Part II: Metals & Alloys, Cobalt, Indian Minerals Yearbook, Vol. 57, 2018, https://ibm.gov.in/index.php?c=pages&m=index&id=1373 [Google Scholar]
  9. K.M. Winslow, S.J. Laux, T. Townsend, A review of the growing concern and potential management strategies of waste lithium-ion batteries, Resour. Conserv. Recycl. 129, 263 (2018) [Google Scholar]
  10. P. Meshram, B.D. Pandey, T.R. Mankhand, H. Deveci, Acid baking of spent lithium-ion batteries for selective recovery of major metals: A two-step process, J. Ind. Eng. Chem. 43, 117 (2016) [Google Scholar]
  11. H. Dang, N. Li, Z. Chang, B. Wang, Y. Zhan, X. Wu, W. Li, Lithium leaching via calcium chloride roasting from simulated pyrometallurgical slag of spent lithium ion battery, Sep. Purif. Technol., 233, 116025 (2020) [Google Scholar]
  12. H. Pinegar, Y.R. Smith, Recycling of end-of-life lithium-ion batteries, Part II: Laboratory-scale research developments in mechanical, thermal, and leaching treatments, J. Sustainable Metall. (2020), https://doi.org/10.1007/s40831-020-00265-8 [Google Scholar]
  13. L. Yun, D. Linh, L. Shui, X. Peng, A.L. Garg, M.L.P. Le, J. Sandoval, Metallurgical and mechanical methods for recycling of lithium-ion battery pack for electric vehicles, Resour. Conserv. Recycl. 136, 198 (2018) [Google Scholar]
  14. G.P. Nayaka, K.V. Pai, G. Santhosh, J. Manjanna, Recovery of cobalt as cobalt oxalate from spent lithium-ion batteries by using glycine as leaching agent, J. Environ. Chem. Eng. 4, 2378 (2016) [Google Scholar]
  15. S. Wang, C. Wang, F. Lai, F. Yan, Z. Zhang, Reduction-ammoniacal leaching to recycle lithium, cobalt, and nickel from spent lithium-ion batteries with a hydrothermal method: Effect of reductants and ammonium salts, Waste Manage. 102, 122 (2020) [CrossRef] [Google Scholar]
  16. S.R. Sunil, S. Vishvakarma, A. Barnwal, N. Dhawan, Processing of spent Li-ion batteries for recovery of cobalt and lithium values, JOM 71, 4659 (2019) [CrossRef] [Google Scholar]
  17. P. Liu, L. Xiao, Y. Chen, Y. Tang, J. Wu, H. Chen, Recovering valuable metals from LiNixCoyMn1 − x yO2 cathode materials of spent lithium-ion batteries via a combination of reduction roasting and stepwise leaching, J. Alloys Compd. 783, 743 (2019) [Google Scholar]
  18. Z. Huang, J. Ruan, Z. Yuan, R. Qiu, Characterization of the materials in waste power banks and the green recovery process, ACS Sustain. Chem. Eng. 6, 3815 (2018) [Google Scholar]
  19. J. Xiao, J. Li, Z. Xu, A novel approach for in situ recovery of lithium carbonate from spent lithium-ion batteries using vacuum metallurgy, Environ. Sci. Technol. 51, 11960 (2017) [Google Scholar]
  20. J. Li, G. Wang, Z. Xu, Environmentally-friendly oxygen-free roasting/wet magnetic separation technology for in situ recycling cobalt, lithium carbonate and graphite from spent LiCoO2/graphite lithium batteries, J. Hazard. Mater. 302, 97 (2016) [Google Scholar]
  21. J. Hu, J. Zhang, H. Li, Y. Chen, C. Wang, A promising approach for the recovery of high value-added metals from spent lithium-ion batteries, J. Power Sources 351, 192 (2017) [Google Scholar]
  22. S.R. Sunil, N. Dhawan, Thermal processing of spent Li-ion batteries for extraction of lithium and cobalt-manganese values, Trans. Indian Inst. Met. 72, 3035 (2019) [CrossRef] [Google Scholar]
  23. Y. Yang, G. Huang, S. Xu, Y. He, X. Liu, Thermal treatment process for the recovery of valuable metals from spent lithium-ion batteries, Hydrometallurgy 165, 390 (2016) [CrossRef] [Google Scholar]
  24. B. Musariri, G. Akdogan, C. Dorfling, S. Bradshaw, Evaluating organic acids as alternative leaching reagents for metal recovery from lithium ion batteries, Miner. Eng. 137, 108 (2019) [CrossRef] [Google Scholar]
  25. S.J. Jose, F.G. Goya, P.M. Calatayud, B.H. Claudia, C.R. Paula, G.G. Rodolfo, Magnetic field-assisted gene delivery: Achievements and therapeutic potential, Curr. Gene Theory 12, 116 (2012) [CrossRef] [Google Scholar]
  26. G. Yang, D. Gao, Z. Shi, Z. Zhang, J. Zhang, J. Zhang, D. Xue, Room temperature ferromagnetism in vacuum-annealed CoO nanospheres, J. Phys. Chem. C. 114, 21989 (2010) [CrossRef] [Google Scholar]
  27. T. Ozkaya, A. Baykal, M.S. Toprak, Y. Koseoğlu, Z. Durmuş, Reflux synthesis of Co3O4 nanoparticles and its magnetic characterization, J. Magn. Magn. Mater. 321, 2145 (2009) [Google Scholar]
  28. W.S. Seo, H.H. Jo, K. Lee, B. Kim, S.J. Oh, J.T. Park, Size‐dependent magnetic properties of colloidal Mn3O4 and MnO nanoparticles, Angewandte Chemie Int. Ed. 43, 1115 (2004) [CrossRef] [Google Scholar]
  29. E.T. Turkdogan, J.V. Vinters, Kinetics of oxidation of graphite and charcoal in carbon dioxide, Carbon 7, 101 (1969) [Google Scholar]
  30. E. Antolini, M. Ferretti, Synthesis and thermal stability of LiCoO2, J. Solid State Chem. 117, 1 (1995) [Google Scholar]
  31. L. Xiaowei, R. Jean-Charles, Y. Suyuan, Effect of temperature on graphite oxidation behavior, Nucl. Eng. Des. 227, 273 (2004) [CrossRef] [Google Scholar]
  32. V. Massarotti, D. Capsoni, M. Bini, Stability of LiMn2O4 and new high temperature phases in air, O2 and N2, Solid State Commun. 122, 317 (2002) [Google Scholar]
  33. F.E. Sesan, Practical reduction of manganese oxides, J. Chem. Technol. Appl. 1, 1 (2017) [Google Scholar]
  34. S. Pindar, N. Dhawan, Recycling of mixed discarded lithium-ion batteries via microwave processing route, Sustain. Mater. Technol. 25, e00157 (2020) [Google Scholar]
  35. D.D.L. Chung, Review graphite, J. Mater. Sci. 37, 1475 (2002) [Google Scholar]
  36. A. Mohammad-Khah, R. Ansari, activated charcoal: Preparation, characterization and applications: A review article, Inter. J. Chem. Tech. Res. 1, 859 (2009) [Google Scholar]

Cite this article as: Sanjay Pindar, Nikhil Dhawan, Evaluation of carbothermic processing for mixed discarded lithium-ion batteries, Metall. Res. Technol. 117, 302 (2020)

All Tables

Table 1

Characteristics of L1 and L3 cathode materials.

Table 2

Process response of different routes at 885 °C, 30% C, 60 min; where G-graphite and C-charcoal.

Table 3

Summary of hydrometallurgical experiments.

Table 4

Overall comparison of different routes followed in this study.

Table 5

Cost and energy calculation of different routes followed.

All Figures

thumbnail Fig. 1

Flowsheet of the experimental procedure used in this work.

In the text
thumbnail Fig. 2

(a) XRD analysis of L1, L3, and anode; Morphology, the composition of (b) L1, (c) L3; (d) TG plot in air atmosphere.

In the text
thumbnail Fig. 3

Proposed reaction mechanism of LCO, LMnO, and LNMO.

In the text
thumbnail Fig. 4

(a) Variation of graphite dosage for L3 (900 °C, 45 min); (b) variation of time at 900 °C, 30% C for L3; (c) temperature effect at fixed dosage (30% C), time (60 min) for L1, L3.

In the text
thumbnail Fig. 5

SEM-EDS of the magnetic fraction at 885 °C, 30%C, 60 min in a muffle furnace for (a) L3-G (b) L3-C, (c) L1-G, (d) L1-C; where G-graphite and C-charcoal.

In the text
thumbnail Fig. 6

(a) Effect of temperature on process responses at 30% C, 60 min in a tube furnace with graphite; SEM-EDS of magnetic fractions at 850 °C, 30% C, 60 min of (b) L3, (c) L1.

In the text
thumbnail Fig. 7

XRD of (a) magnetic fractions, (b) solution crystal, of L1, L3 at optimum conditions (muffle furnace: 885 °C, 30% C, 60 min; tube furnace: 850 °C, 30% C, 60 min); (G-graphite and C-charcoal).

In the text

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.