Environmental Technology, 2013 Vol. 34, No. 10, 1307–1317, http://dx.doi.org/10.1080/09593330.2012.746734
Selective recovery of valuable metals from spent Li-ion batteries using solvent-impregnated resins Fuqiang Guo, Syouhei Nishihama and Kazuharu Yoshizuka∗ Department of Chemical Engineering, The University of Kitakyushu, Kitakyushu, Japan (Received 17 April 2012; final version received 30 October 2012 ) Selective recovery of valuable metals (Cu2+ , Co2+ and Li+ ) from leachate of spent lithium-ion (Li-ion) batteries was investigated in acidic chloride media using solvent impregnated resins (SIRs). An SIR containing bis(2-ethylhexyl) phosphoric acid (D2EHPA) had high selectivity for Fe3+ and Al3+ , with an order of selectivity Fe3+ > Al3+ > Cu2+ > Co2+ . Fe3+ and Al3+ could be removed from synthetic leachate by precipitation, followed by column adsorption with the SIR containing D2EHPA. The synthetic leachate was then applied to chromatography for selective recovery of Cu2+ , Co2+ and Li+ . The solution was first fed upward to a column packed with an SIR containing 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC-88A) for selective separation of Cu2+ , followed by upward feed to another column packed with an SIR comprising PC-88A and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) for selective recovery of Co2+ . Finally, a column packed with a synergistic SIR containing both 1-phenyl-1,3-tetradecanedione (C11 phβDK) and tri-n-octylphosphine oxide (TOPO) was used for selective recovery of Li+ . A process flowsheet is proposed for selective recovery of Cu2+ , Co2+ and Li+ using several SIRs. This process was found to be simple and efficient for selective recovery of valuable metals from leachate of spent Li-ion batteries. Pure copper, cobalt and lithium products were obtained, with high elution yields. Keywords: Li-ion battery; adsorption; recovery; solvent impregnated resins; PC-88A; Cyanex 272
1. Introduction Lithium-ion batteries (LIBs) are one of the most popular types of rechargeable cell, because they are light in weight, have high energy density, high battery voltage, no memory effect, a long charging-discharging cycle and operate over a wide temperature range [1–3]. Because of their excellent electrochemical properties, safety and acceptable environmental effects, LIBs have been widely used as electrochemical power sources in mobile telephones, laptop computers, video-cameras and other modern electronic equipment [4,5]. The annual global production and consumption of LIBs have been rapidly rising. However, their inappropriate disposal may cause environmental concerns because of the generation of hazardous waste from flammable and toxic elements or compounds, even though spent LIBs are not generally classified as dangerous waste [6,7]. Recycling of spent LIBs has increasingly become an important issue faced by many countries. Simultaneously, spent LIBs are considered as secondary resources or the so-called ‘urban mine’ and economic benefits could be achieved in recovery of major components from spent LIBs [8,9]. Some of the metals in LIBs can be found at higher concentration levels than those typically found in processing concentrates of natural ores or natural ores themselves [10]. The recovery of valuable metals from spent LIBs is ∗ Corresponding
author. Email: [email protected]
© 2013 Taylor & Francis
thus highly desirable for protecting natural resources and the environment either at the present time or in the near future. Various processes have been reported for separation or recovery of metals from spent LIBs and these can be classified into two general categories: physical and chemical processes. Several of the existing processes for recycling LIBs use various types of thermal treatment, while others are fully mechanical. Most processes are focused on cobalt recovery but do not recover lithium as a refined product. Solvent extraction, an effective chemical technology, has been applied to the recovery of metals from spent LIBs, because of its simple operation, inexpensive equipment and the easy recovery and recycle of the solvents. In a joint recycling venture between Sony and Sumitomo Metal Mining in Ehime, Japan, standard hydrometallurgical methods are used to recover cobalt from active cathode materials after untreated LIBs are incinerated at 1000°C, while lithium is not a target for recovery [11]. Zhang et al. reported a hydrometallurgical process for separation and recovery of cobalt and lithium from spent LIBs [12]. It was found that solvent extraction with 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC-88A) was quite effective in separating cobalt from lithium to obtain highpurity cobalt product. A reductive leaching and solvent extraction
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process using bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) was developed for recovery of cobalt sulphate from spent LIBs by Kang et al. [13]. After reductive leaching and removal of metal ion impurities such as copper, iron and aluminium, cobalt was selectively extracted from the purified aqueous phase with 50% saponified 0.4 mol/L Cyanex 272. Overall, 92% cobalt could be recovered from spent LIBs. Dorella et al. investigated a hydrometallurgical route consisting of the following steps, focusing on recovery of cobalt from spent LIBs: (1) manual dismantling, (2) manual separation of anode/cathode, (3) leaching with sulphuric acid in an oxidizing environment, (4) precipitation with NH4 OH and (5) solvent extraction with Cyanex 272, to separate cobalt from lithium [14]. Nan et al. reported a recycling process for valuable metal from spent LIBs using chemical deposition and solvent extraction [15]. The mass cobalt was chemically deposited as oxalate; and 5-nonylsalicylaldoxime (Acorga M 5640) and Cyanex 272 were efficient and selective for extraction of copper and cobalt in sulphate solution. A mixed extractant system was developed for the separation and purification of cobalt and lithium from spent LIB leach solutions by Cheng et al. [16] A process flowsheet has been proposed for recovering cobalt and lithium from spent lithium-ion battery leach solutions using the mixed Ionquest 801 and Acorga M5640 system in the first solvent extraction circuit and Cyanex 272 in the second solvent extraction circuit. The solvent extraction technology thus provides an exciting opportunity for the recycling of spent LIBs. Recently, disadvantages of the solvent extraction method, such as the intense mixing of phases, the requirement for large amounts of organic solvent, the third phase formation and the loss of organic solvent into the aqueous phase, have been pointed out. Therefore, there is intense interest in creating a technology combining the advantages of solvent extraction with those of adsorption and/or ion exchange. Solvent impregnated resins (SIRs) [17–21] and microcapsules encapsulating extractant [22–25] have been investigated as a second-generation extraction system. SIRs are easily prepared by treating a polymer resin with an organic solvent containing extractants, and has been shown to produce effective adsorbents for selective separation and removal of metals, even at low concentrations. Akita and Takeuchi conducted the adsorption of Zn2+ , Cu2+ , Co2+ and Ni2+ using SIRs containing bis(2-ethylhexyl) phosphoric acid (D2EHPA) and PC-88A to attain the selective separation of Zn2+ /Cu2+ and Co2+ /Ni2+ [26]. Levextrel resin (a microcapsule resin) containing Cyanex 272 was applied for the adsorptive separation of Co2+ and Ni2+ from aqueous ammonium nitrate and sulphate solutions by Yoshizuka et al. [27]. Kabay et al. investigated the extraction of Cd2+ and Cu2+ from phosphoric acid with SIRs containing bis(2,4,4-trimethylpentyl) monothiophosphinic acid (Cyanex 302) [28]. The separation of Cd2+ , Fe3+ and Ni2+ using SIRs containing Cyanex 272 and Cyanex 302 was investigated by Gonzalez et al. [18]. SIRs impregnated
with acidic organophosphorus extractants are feasible for separating or recovering a number of metal ions from industrial toxic sludges, metal-bearing wastewater and various secondary resources. Acidic organophosphorus extractants were recommended by Meyer et al. for selective extraction of iron and aluminium from acidic solution [29]. D2EHPA was reported to be an effective extractant for extracting Fe3+ and Al3+ from aqueous solution [30–32] and is normally used for removal of Fe3+ and Al3+ to attain desired purity of metals in hydrometallurgical processing operations. In previous work, it was found that an SIR containing PC-88A had high selectivity for Cu2+ and the order of selectivity was Cu2+ > Co2+ > Ni2+ [33]. Moreover, the adsorption of Co2+ and Ni2+ could be significantly suppressed by the high selectivity for Cu2+ of a PC-88A SIR in Cu2+ , Co2+ and Ni2+ ternary metal systems. The separation of Cu2+ from co-existing Co2+ and Ni2+ can be achieved with a PC-88A SIR by controlling the pH of the aqueous solution. In previous work, high selectivity for Co2+ was observed using an SIR containing Cyanex 272, and Co2+ could be effectively separated from binary metal solutions containing Co2+ and Ni2+ by chromatographic operation [33]. The adsorptive separation of Li+ with a synergistic SIR impregnated with both 1-phenyl-1,3-tetradecanedione (C11 phβDK) and trin-octylphosphine oxide (TOPO) was also investigated in aqueous chloride media in previous work [34], showing high selectivity for Li+ over Na+ and K+ . Li+ could thus be effectively separated from aqueous solution containing a large excess of Na+ concentration by chromatographic operation. In this study, a recycling process for selective recovery of valuable metals (Cu2+ , Co2+ and Li+ ) from synthetic leachate of spent LIBs by solvent impregnated resins (SIRs) was investigated. SIRs impregnated with 3 types of acidic organophosphorus extractants were applied not only to remove Fe3+ and Al3+ , but also to recover Cu2+ and Co2+ . Selective recovery of Li+ could be achieved by using an SIR containing both C11 phβDK and TOPO. A recycling process flowsheet is proposed for mutual recovery of Cu2+ , Co2+ and Li+ from spent LIBs using SIRs. 2. Experimental 2.1. Materials A synthetic leachate containing 133.1 mmol/L Cu2+ , 358.0 mmol/L Co2+ , 353.0 mmol/L Li+ , 135.2 mmol/L Al3+ and 1.1 mmol/L Fe3+ was prepared by dissolving the corresponding metal chlorides in hydrochloric acid solution. The composition of the synthetic leachate was analogous with that of leachate from a spent Li-ion battery (Panasonic CGR18650H type) with a cylindrical shape from a laptop computer, as described previously [33]. DIAION HP2MG, a methacrylic ester copolymer, was kindly supplied by Nippon Rensui Co., Ltd and used as a polymer support for preparing SIRs. The structure of
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(a) 300 250
[Mx+] (mmol/L)
200 150 100
Cu2+ Co2+ Li+ Fe3+ Al3+
10 5 0 0
2
4
6
8
10
12
14
16
18
Bed volume (-)
(b) 160 140
[Mx+] (mmol/L)
120 100 80
Cu2+ Co2+ Li+ Fe3+ Al3+
60 40 20 0 0
1
2
3
4
5
6
Bed volume (-) Figure 1. (a) Breakthrough and (b) elution profiles for Fe3+ and Al3+ with D2EHPA SIR. pH = 2.66, [Cu2+ ]feed = 96.5 mmol/L, [Co2+ ]feed = 257.6 mmol/L, [Al3+ ]feed = 13.0 mmol/L, [Fe3+ ]feed = 0.04 mmol/L, [Li+ ]feed =249.0 mmol/L. Flow rate = 0.1 mL/ min. Breakthrough BV for Al3+ = 11.3, breakthrough BV for Fe3+ = 2. Breakthrough capacity for Al3+ = 4.84 mmol, breakthrough capacity for Fe3+ = 0.003 mmol. Total capacity of resin for Al3+ = 6.40 mmol, total capacity of resin for Fe3+ = 6.00 mmol. Elution efficiency for Al3+ = 61.4%, elution efficiency for Fe3+ = 87.8. Utilization rate of SIR for Al3+ = 75.8%, utilization rate of SIR for Fe3+ = 0.3%.
HP2MG is shown in Figure S1 (See Appendix), and its particle size distribution ranges from 25 to 50 mesh (>90%). The specific surface area, pore volume and pore radius of HP2MG are reported by the manufacturer to be 570 m2 /g, 1.3 mL/g and 24 nm, respectively. The commercial extractants used were D2EHPA, PC88A and Cyanex 272, supplied by Nacalai Tesque, Inc., Daihachi Chemical Industry and Nihon Cytec Industries
Inc., respectively. TOPO was supplied by Tokyo Chemical Industry. All other organic and inorganic reagents were analytical grade and supplied by Wako Pure Chemistry Industries. All reagents were utilized as received, without further purification. C11 phβDK was synthesized according to the procedure reported in a previous paper [34]. The product was identified by a proton nuclear magnetic resonance
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spectrometer (1 HNMR, JEOL JMM-ECP500), a Fourier transform infrared spectrophotometer (FTIR, Shimadzu FTIR-8400S) and an Elementary Analyzer (Yanaco, MT6 Corder). The results were as follows: C, 79.26; H, 9.87%. Calculated for C20 H30 O2 : C, 79.42; H, 10.00%. 2.2.
ions in the aqueous solutions were analyzed by an inductively coupled plasma atomic emission spectrometer (ICPAES, Shimadzu ICPS-7000), to determine the corresponding adsorption amounts at equilibrium, qM (mmol/g). qM was calculated from the difference in metal concentration in the aqueous phase before and after adsorption as follows:
Preparation of SIR
SIRs containing D2EHPA, PC-88A, Cyanex 272 or C11 phβDK and TOPO were prepared by the following method [33,34]. HP2MG was washed with methanol and dried in vacuo. The washed resin was immersed overnight in a toluene solution containing D2EHPA, PC-88A, Cyanex 272 or C11 phβDK and TOPO. The toluene was then removed by evaporation and the resin was dried in vacuo for 24 h. The amount of the extractant impregnated in the resin was determined by the difference in weight before and after impregnation. The amounts of D2EHPA and PC88A impregnated in the resins were 1.22 and 1.24 mmol/g, respectively. The SIR containing PC-88A and Cyanex 272 with a mole ratio of PC-88A/Cyanex 272 = 5/1 was also prepared with 1.01 mmol/g of PC-88A and 0.19 mmol/g of Cyanex 272. SIRs used for adsorption of Li+ were impregnated with 0.66 mmol/g of both C11 phβDK and TOPO. The SIRs containing D2EHPA, PC-88A and Cyanex 272 were coated with a hydrophilic polymer to prevent leakage of the extractant [21,33,35]. The coating agent was prepared by dissolving 3 g of polyvinyl alcohol (PVA, polymerization degree = ca. 2000) and 1 g of acetamide in 96 g of de-ionized water under heating and magnetic stirring. In a typical procedure, 3 g of vacuum-dried SIR was immersed in 50 mL of PVA solution and shaken for 17 h. Then, 10 mL of 1 mol/L KCl solution was added and shaken for 24 h. The SIR was filtered off from the solution and re-suspended in 10 mL of 0.32 mol/L H2 SO4 . 10 mL of 0.32 mol/L glutaraldehyde solution was then added to the suspended solution and shaken for 24 h. Finally, the SIR was filtered, washed with a large excess of de-ionized water and dried in vacuo. The SIR containing C11 phβDK and TOPO was not coated but was simply treated with an aqueous solution of 0.1 wt% sodium lauryl sulphate to make the surface of the resin hydrophilic prior to chromatographic operation. 2.3. Batchwise adsorption of metal ions Aqueous solutions of metal ions were prepared by dissolving the corresponding metal chlorides in hydrochloric acid solution. The concentration of each metal ion for pH dependence experiments was set to 1.0 mmol/L. 20 mg of SIR was added to 10 mL of aqueous solution. The pH was adjusted by adding an appropriate amount of hydrochloric acid or sodium hydroxide to the aqueous solution. The mixture was shaken vigorously at 298 K for more than 12 h to attain equilibrium. After filtration, the equilibrium pH was measured by a pH meter (Horiba F-23). The concentration of metal
qM =
([M]initial − [M]) · L w
(1)
where [M]initial (mmol/L) and [M] (mmol/L) are the initial and equilibrium concentrations of metal ion in the aqueous phase, respectively, L (L) is the volume of aqueous solution and w (g) is the weight of SIR. 2.4.
Chromatographic operation for metal recovery
A sample of 20.0 g of SIR (wet volume = 40.0 mL) was packed into a column 20 mm in diameter and washed with de-ionized water. The aqueous feed solution to SIR was fed upward through the column at a flow rate of 0.1 mL/min (space velocity (SV) = 0.15 h−1 ), using a dualplunger pump (EYELA, KP-11). The pH of the aqueous feed solution was adjusted by adding an appropriate amount of hydrochloric acid or sodium hydroxide to the aqueous solution. In some cases, sodium acetate/acetic acid buffer solution was used. After breakthrough of metal ions, de-ionized water was fed into the column to wash out residual feed solution. The loaded metal ions were then eluted with 1.0 mol/L HCl solution. The effluents were collected with a fraction collector (EYELA, DC-1500). The pH values and metal concentrations were determined by a pH meter and ICP-AES or an atomic absorption spectrometer (AAS, Shimadzu AAS-6800), respectively. Bed volume (BV) of the effluent is defined as BV =
vt V
(2)
where v (mL/min), t(min) and V (mL) are the flow rate of solution, the time for which feed solution was supplied and the wet volume of adsorbent, respectively. 3. Results and discussion 3.1. Removal of Fe3+ and Al3+ 3.1.1. Removal of Fe3+ and Al3+ by chemical precipitation Chemical precipitation with NaOH was used to remove Fe3+ and Al3+ from synthetic leachate. The concentration of metal ions in synthetic leachate before and after precipitation is listed in Table 1. Over 90% of Fe3+ and 85% of Al3+ were removed as their hydroxides by adjusting pH to 4.1 with 1.0 mol/L NaOH. The total losses of Co2+ and Li+ were 1.3% and 3.1%, respectively. Although ca. 3.3% of Cu2+ was lost, the loss of metal ions is attributed to a
Environmental Technology Table 1. Metal concentrations in the synthetic leachate before and after precipitation. Li Initial concentration∗ (mmol/L) Concentration at pH 4.1† (mmol/L) Loss‡ (%)
Cu
Co
Al
Fe
353.0 133.1 358.0 135.2
1.1
341.9 128.7 353.5
19.1
0.1
85.9
90.9
3.1
3.3
1.3
∗ Metal
concentrations in synthetic leachate [33]. concentrations after adjusting the pH to 4.1 with 1.0 mol/L NaOH solution. ‡ Percentage metal loss from synthetic leachate to the residue, based on mass balance. † Metal
too high local concentration of OH− in synthetic leachate or incorporation with hydroxide solids during precipitation. The small amount of residual Fe3+ and Al3+ in the solution would be removed by column adsorption with the D2EHPA SIR. 3.1.2. Complete removal of Fe3+ and Al3+ by chromatographic operation with the D2EHPA SIR After chemical precipitation of Fe3+ and Al3+ , small amounts of Fe3+ and Al3+ remained in the solution, so D2EHPA SIR was used to remove them. The effect of equilibrium pH on the amounts of metal ions adsorbed from single metal systems is shown in Figure S2. The characteristic curves are similar to one another, exhibiting strong dependence of metal ion adsorption behaviour on pH. The adsorption ability of the D2EHPA SIR for the metal ions followed the order: Fe3+ > Al3+ > Cu2+ > Co2+ . Fe3+ and Al3+ were strongly adsorbed when pH was around 2.0 and 2.6, respectively, while Cu2+ and Co2+ were hardly adsorbed. Therefore, through pH control, the D2EHPA SIR could be used for the complete removal of Fe3+ and Al3+ from an aqueous solution also containing Cu2+ and Co2+ . Based on batchwise experiments, the chromatographic separation of Fe3+ and Al3+ from synthetic aqueous solution (after removal of Fe3+ and Al3+ by chemical precipitation) was conducted using the D2EHPA SIR. Figure 1(a) shows the breakthrough profiles for Fe3+ and Al3+ . Fe3+ and Al3+ were selectively adsorbed, while Cu2+ , Co2+ and Li+ were scarcely adsorbed. As shown in the elution profiles in Figure 1(b), Fe3+ and Al3+ were quantitatively eluted by 1.0 mol/L HCl solution, while Cu2+ , Co2+ and Li+ were not eluted. Therefore, the complete removal of Fe3+ and Al3+ from the aqueous solution was achieved using the D2EHPA SIR. The effluent collected before the breakthrough of Fe3+ and Al3+ was used for the recovery of valuable metals as described below. 3.2. Separation and recovery of Cu2+ After complete removal of Al3+ and Fe3+ , Cu2+ , Co2+ and Li+ remained in the aqueous solution. The concentrations
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of metals in the aqueous solution are shown in Table 2. A PC-88A SIR was used first for selective recovery of Cu2+ from the aqueous solution. Chromatographic separation of Cu2+ from the aqueous solution after removal of Al3+ and Fe3+ was conducted using the PC-88A SIR. Figure 2(a) shows the breakthrough profiles of Cu2+ , Co2+ and Li+ . Cu2+ was selectively adsorbed, while Li+ was scarcely adsorbed. A small amount of Co2+ was adsorbed in the column before the breakthrough of Cu2+ . Figure 2(b) shows the elution profiles for Cu2+ , Co2+ and Li+ with 1.0 mol/L HCl solution. Cu2+ was quantitatively eluted with an elution yield of greater than 94%, while no Li+ was eluted. The maximum concentration of Cu2+ reached 150 mmol/L. Although the adsorbed Co2+ primarily loaded in the column could be replaced by competing Cu2+ , as shown in Figure 2(a), little Co2+ remained in the column. This Co2+ fraction may be eluted together with Cu2+ , resulting in a loss of metal. Because Cu2+ has a much higher concentration than Co2+ in the eluent, the adsorption of Co2+ could be markedly suppressed by the high selectivity for Cu2+ of the PC-88A SIR. The fraction of Co2+ in the eluent could be separated and recovered by passing the eluent through a column packed with PC-88A SIR. Figure S3 shows the breakthrough and elution profiles for Cu2+ separation and purification from an eluent with the PC-88A SIR. Cu2+ was selectively adsorbed, while Co2+ was scarcely adsorbed. The effluent collected before breakthrough of Cu2+ contained only Co2+ enabling its recovery, as shown in the elution profiles for Cu2+ and Co2+ with 1.0 mol/L HCl solution. Cu2+ was quantitatively eluted with a high purity of ca. 100% at BV = 1.5, while little Co2+ was eluted. The maximum concentration of Cu2+ was 178 mmol/L. 3.3.
Recovery of Co2+
Although the SIR containing Cyanex 272 exhibited excellent selectivity for Co2+ over Ni2+ [33], Cyanex 272 is more expensive than PC-88A. Because Ni2+ in the leachate of spent LIBs comes mainly from the steel shell, the concentration of Ni2+ is much lower than that of Co2+ . Therefore, a SIR containing both PC-88A and Cyanex 272 was used to recover Co2+ from the aqueous solution. Figure S4 shows the effect of pH on the amounts of metal ions adsorbed by SIRs with different ratios of PC88A/Cyanex 272 in a binary system of Co2+ and Ni2+ . The adsorption behaviours were almost the same for all PC-88A/Cyanex 272 ratios. At pH < 4.3, the amount of Co2+ adsorbed by the PC-88A/Cyanex 272 SIR increased with increasing PC-88A/Cyanex 272 ratio in the order: 1/5 < 1/2 < 1/1 < 5/1. The synergistic effect is distinct in the case of the 5/1 PC-88A/Cyanex 272 ratio SIR, in agreement with those in solvent extraction systems [36]. The adsorption of Ni2+ is markedly suppressed by high Co2+ selectivity.
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(a) 300
[Mx+] (mmol/L)
250
Co2+ Li+ Cu2+
200
150 100 50
0 0
1
2
3
4
5
Bed volume (-)
(b)
[Mx+] (mmol/L)
150
100
Cu2+ Co2+ Li+
50
0 0
1
2
3
4
5
Bed volume (-) Figure 2. (a) Breakthrough and (b) elution profiles for Cu2+ with PC-88A SIR. pH = 4.19, [Cu2+ ]feed = 94.5 mmol, [Co2+ ]feed = 257.3 mmol, [Li+ ]feed = 247.1 mmol. Flow rate = 0.1 mL/min. Breakthrough BV for Cu2+ = 2.1, breakthrough BV for Co2+ = 0.1. Breakthrough capacity for Cu2+ = 7.97 mmol, breakthrough capacity for Co2+ = 1.03 mmol. Total capacity of resin for Cu2+ = 8.40 mmol, total capacity of resin for Co2+ = 7.00 mmol. Elution efficiency for Cu2+ = 94.7%, elution efficiency for Co2+ = 53.7%. Utilization rate of SIR for Cu2+ = 101.7%, utilization rate of SIR for Co2+ = 74.7%.
A column packed with a 5/1 PC-88A/Cyanex 272 ratio SIR was used for the chromatographic separation of Co2+ from the aqueous solution after recovering Cu2+ . The breakthrough profiles for Co2+ and Li+ on the column are shown in Figure 3(a). The breakthrough point was around BV = 1.2, after which the concentration of Co2+ in the effluent rapidly increased. Co2+ was selectively adsorbed, while Li+ was scarcely adsorbed. The excess
concentrations on the breakthrough curves for Li+ were caused by the displacement effects of the competing Co2+ . An aliquot fraction of Li+ previously loaded on the column can be replaced by Co2+ when insufficient adsorption sites are available [37,38]. The column was then eluted with 1.0 mol/L HCl solution after the adsorption process was completed. As shown in the elution profiles of Co2+ and Li+ in Figure 3(b), Co2+ was quantitatively eluted to
Environmental Technology
3.4. Recovery of Li+ After recovery of Cu2+ and Co2+ , only the alkali metals, Li+ and Na+ , remained in the aqueous solution. The concentration of Na+ was much higher than that of Li+ because a large amount of NaOH was added into the solution to adjust the pH. Therefore, an SIR containing C11 phβDK and TOPO was used to recover Li+ from the aqueous solution after chromatographic recovery of Cu2+ and Co2+ . Figure S5 shows the breakthrough profiles for Li+ from the aqueous solution with the C11 phβDK/TOPO SIR. Li+
Table 2. Metal concentrations in the synthetic aqueous solution used for chromatographic operation with PC-88A SIR.
Concentration (mmol/L)
Cu
Co
Li
Al
Fe
94.5
257.3
247.1
0
0
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obtain a high purity of almost 100% at BV = 1.4, while no Li+ was eluted. The maximum concentration of Co2+ was 223 mmol/L.
(a) 300
[Mx+] (mmol/L)
250 200 150 100
Co2+ Li+
50 0 0.0
0.5
1.0
1.5
2.0
2.5
Bed volume (-)
(b) 250
x+
[M ] (mmol/L)
200
150
100
Co2+ Li+
50
0 0
1
2
3
4
5
6
7
Bed volume (-) Figure 3. (a) Breakthrough and (b) elution profiles for with PC-88A/Cyanex 272 SIR. pH = 5.17, [Co2+ ]feed = 244.1 mmol/L, [Li+ ]feed = 243.7 mmol/L. Flow rate = 0.1 mL/min. Breakthrough BV for Co2+ = 1.2. Breakthrough capacity for Co2+ = 8.79 mmol. Total capacity of resin for Co2+ = 9.49 mmol. Elution efficiency for Co2+ = 93.1%. Utilization rate of SIR for Co2+ = 94.9%. Co2+
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(a) 4000 3500 3000
+
[M ] (mmol/L)
2500 2000 1500 1000
Li+ Na+
400 300 200 100 0 0
1
2
3
4
Bed volume (-)
(b) 500
300
200
+
[M ] (mmol/L)
400
Li+ Na+
100
0 0
1
2
3
4
Bed volume (-) Figure 4. (a) Breakthrough and (b) elution profiles for with C11 phβDK/TOPO SIR. pH = 12.29, [Li+ ]feed = 234.0 mmol/L, [Na+ ]feed = 3529.2 mmol/L. Flow rate = 0.1 mL/min. Breakthrough BV for Li+ = 0.8. Breakthrough capacity for Li+ = 7.49 mmol. Total capacity of resin for Li+ = 14.82 mmol. Elution efficiency for Li+ = 93.9%. Utilization rate of SIR for Li+ = 123.5%. Li+
was selectively adsorbed, while Na+ was scarcely adsorbed. Figure 4(b) shows the elution profiles for Li+ and Na+ with 1.0 mol/L HCl solution. Li+ was quantitatively eluted with a high purity of almost 100% at BV = 1.5, while no Na+ was eluted. The elution yield of Li+ was more than 93% and the maximum concentration of Li+ was 441 mmol/L. 3.5. Reusability of SIRs To apply the SIRs to chromatographic separation and recovery on an industrial scale, the reusability of the SIRs
is important. The reuse performances of SIRs were examined. Figure 5 shows the breakthrough and elution profiles of Co2+ and Li+ using the PC-88A/Cyanex 272 SIR. The adsorption-elution process cycle was conducted five times with the same column. The breakthrough profiles for the first and fifth cycles indicated no decline in adsorption-elution profile and the elution profiles during the five cycles were essentially the same as those in Figure 3(b). This indicates that the PC-88A/Cyanex 272 SIR is suitable for column operation as well, as it has sufficient loading capacity for use in repeated processing. The reusability and stability of
Environmental Technology Spent Li-ion batteries
Dismantling of case 2 mol/L HCl, 70°C, 5 h Leachate Cu2+, Co2+, Li+, Al3+, Fe3+, pH 4.1 Removal of Al and Fe 2+
Al(OH)3, Fe(OH)3 2+
+
Cu , Co , Li , little Al3+, Fe3+, pH 2.6
2+
+
D2EHPA SIR
Al, Fe
2+
Cu , Co , Li , pH 4.2 PC-88A SIR 2+
Cu +
Co , Li , pH 5.2 PC-88A/Cyanex272 SIR
Co
Li+, pH 12.3 C11
/TOPO SIR
Li
Figure 5. A process flowsheet for recovery of valuable metals from spent Li-ion batteries using SIRs.
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4. Conclusions The selective recovery of valuable metals (Cu2+ , Co2+ , Li+ ) from the leachate of spent LIBs by SIRs was investigated in acidic chloride media. A D2EHPA SIR has high selectivity for Fe3+ and Al3+ , with selectivity in the order Fe3+ > Al3+ > Cu2+ > Co2+ . Fe3+ and Al3+ could be easily removed from the aqueous solution by chemical precipitation, followed by chromatographic separation with D2EHPA SIR. The separation and recovery of Cu2+ from the aqueous solution could be achieved using a PC88A SIR. A high selectivity for Co2+ was observed with a PC-88A/Cyanex 272 SIR, enabling effective chromatographic separation of Co2+ . Finally, a C11 phβDK/TOPO SIR was used for selective recovery of Li+ . Thus, the selective recovery of Cu2+ , Co2+ and Li+ from the leachate of spent LIBs was achieved via one chemical precipitation and four chromatographic operations. A process flowsheet was then proposed for recovery of Cu2+ , Co2+ and Li+ using SIRs. Acknowledgements We are grateful for financial support through a Grant-in-Aid for Scientific Research (No. K2127, K22091 and K2340) from the Ministry of Environment of Japan.
the other SIRs used in this study were confirmed in previous works [33,34].
References
Process flowsheet for selective recovery of Cu2+ , Co2+ and Li+ from spent LIBs A process flowsheet for selective recovery of Cu2+ , Co2+ and Li+ from spent LIBs using several SIRs is proposed here, as shown in Figure 5. During the procedures of dismantling and acid leaching of spent LIBs, the isolation of anode and cathode materials from the copper foil and aluminium foil is unnecessary. Both anode and cathode films are leached by HCl solution. Most of the iron and aluminium is removed by adjusting the pH of the leachate. The small amounts of Al3+ and Fe3+ remaining in solution are removed by the first chromatographic operation with the D2EHPA SIR, and the effluent contains copper, cobalt and lithium. In the second chromatographic operation, using the PC-88A SIR, copper is recovered by adsorption on the column and the effluent contains cobalt and lithium. Cobalt could be completely separated from lithium after the effluent is fed through the third chromatographic operation using the PC-88A/Cyanex 272 SIR. Finally, the C11 phβDK/TOPO SIR can be used to recover lithium. Compared with solvent extraction, chromatographic operation using SIRs does not require intensive mixing of phases, multistage cycles of extraction and striping or large amounts of organic solvent. The main advantage of the proposed process is the simplification of the recycling process for spent LIBs.
[1] E. Plichta, M. Salomon, S. Slane, M. Uchiyama, D. Chua, W.B. Ebner, and H.W. Lin, A rechargeable Li/Lix CoO2 Cell, J. Power Sources 21 (1987), pp. 25–31. [2] C.M. Sabin, Battery paste recycling process, Patent 5,690,718, USA, 1997. [3] A. Lundblad and B. Bergman, Synthesis of LiCoO2 starting from carbonate precursors II. Influence of calcination conditions and leaching, Solid State Ionics 96 (1997), pp. 183– 193. [4] J. Nan, D. Han, and X. Zuo, Recovery of metal values from spent lithium-ion batteries with chemical deposition and solvent extraction, J. Power Sources 152 (2005), pp. 278–284. [5] D.I. Ra and K.S. Han, Used lithium ion rechargeable battery recycling using Etoile-Rebatt technology, J. Power Sources 163 (2006), pp 284–288. [6] S. Castillo, F. Ansart, C. Laberty-Robert, and J. Portal, Advance in the recovering of spent lithium battery compounds, J. Power Sources 112 (2002), pp. 247–254. [7] J.C. Alfonso, N.G. Busnardo, and R.G. Busnardo, Global Symposium on Recycling, Waste Treatment and Clean Technology, in Proceedings of REWAS 2004, Vol. III, I. Gaballah, B. Mishra, R. Solozobal and M. Tanaka, eds., TMS, Warrendale, Pennsylvania, USA, 2004, pp. 2783– 2785. [8] B.R. Conard, The role of hydrometallurgy in achieving sustainable development, Hydrometallurgy 30 (1992), pp. 1–28. [9] J.Q. Xu, H.R. Thomas, R.W. Francis, K.R. Lum, J.W. Wang, and B. Liang, A review of processes and technologies for the recycling of lithium-ion secondary batteries, J. Power Sources 177 (2008), pp. 512–527. [10] G. Dorella and M. B. Mansur, A study of the separation of cobalt from spent Li-ion battery residues, J. Power Sources 170 (2007), pp. 210–215.
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[11] M.J. Lain, Recycling of lithium ion cells and batteries, J. Power Sources 97–98 (2001), pp. 736–738. [12] P.W. Zhang, T. Yokoyama, O. Itabashi, T.M. Suzuki, and K.Inoue, Hydrometallurgical process for recovery of metal values from spent lithium-ion secondary batteries, Hydrometallurgy 47 (1998), pp. 259–271. [13] J. Kang, G. Senanayake, J. Sohn, and S.M. Shin, Recovery of cobalt sulfate from spent lithium ion batteries by reductive leaching and solvent extraction with Cyanex 271, Hydrometallurgy 100 (2010), pp. 168–171. [14] G. Dorella and M.B. Mansur, A study of the separation of cobalt from spent Li-ion battery residues, J. Power Sources 170 (2007), pp. 210–215. [15] J.M. Nan, D.M. Han, and X.X. Zuo, Recovery of metal values from spent lithium-ion batteries with chemical deposition and solvent extraction, J. Power Sources 170 (2007), pp. 210–215. [16] Y. Pranolo, W. Zhang, and C.Y. Cheng, Recovery of metals from spent lithium-ion battery leach solutions with a mixed solvent extraction system, Hydrometallurgy 102 (2010), pp. 37–42. [17] R.S. Juang and M.L. Chen, Application of the Elovich equation to the kinetics of metal sorption with solventimpregnated resins, Ind. Eng. Chem. Res. 36 (1997), pp. 813–820. [18] M.P. Gonzalez, I. Saucedo, R. Navarro, M. Avila, and E. Guibal, Selective separation of Fe(III), Cd(II), and Ni(II) from dilute solutions using solvent-impregnated resins, Ind. Eng. Chem. Res. 40 (2001), pp. 6004– 6013. [19] C.Y. Shiau, C.L. Lin, and H.S. Chang, Adsorption equilibrium of zinc from aqueous sulfate solution by solventimpregnated resins containing Cyanex 272, Ind. Eng. Chem. Res. 44 (2005), pp. 4771–4777. [20] T. Nakamura, T. Ikawa, S. Nishihama, and K. Yoshizuka, Selective recovery of indium from acid sulfate media with solvent impregnated resin of bis(4-cyclohexylcyclohexyl) phosphoric acid as an extractant, Ion Exch. Lett. 2 (2009), pp. 22–26. [21] N. Kabay, J.L. Cortina, A. Trochimczuk, and M. Streat, Solvent-impregnated resins (SIRs) – Methods of preparation and their applications, React. Funct. Polym. 70 (2010), pp. 484–496. [22] E. Kamio and K. Kondo, Separation of rare metal ions by a column packed with microcapsules containing an extractant, Ind. Eng. Chem. Res. 41 (2002), pp. 3669– 3675. [23] S. Nishihama, G. Nishimura, T. Hirai, and I. Komasawa, Separation and recovery of Cr(VI) from simulated plating waste using microcapsules containing quaternary ammonium salt extractant and phosphoric acid extractant, Ind. Eng. Chem. Res. 43 (2004), pp. 751–757. [24] E. Kamio, M. Matsumoto, and K. Kondo, Theoretical development of metal extraction mechanism into an extractantimpregnated microcapsule, Ind. Eng. Chem. Res. 46 (2007), pp. 255–265. [25] X. Gong, Y. Lu, Z. Qian, and G. Luo, Preparation of uniform microcapsules containing 1-octanol for caprolactam extraction, Ind. Eng. Chem. Res. 48 (2009), pp. 4507–4513. [26] S. Akita and H. Takeuchi, Sorption and separation of divalent metals by a macromolecular resin containing organophosphorus acids, J. Chem. Eng. Data 37 (1992), pp. 303–306. [27] K. Yoshizuka, Y. Sakomoto, Y. Baba, and K. Inoue, Distribution equilibria in the adsorption of cobalt(II) and nickel(II)
[28]
[29] [30] [31] [32]
[33]
[34]
[35]
[36]
[37]
[38]
on Levextrel resin containing Cyanex 272, Hydrometallurgy 23 (1990), pp. 309–318. N. Kabay, M. Demircio˘glu, H. Ekinci, M. Yüksel, M. Sa˘glam, and M. Streat, Extraction of Cd(II) and Cu(II) from phosphoric acid solutions by solvent-impregnated resins (SIR) containing Cyanex 302, React. Funct. Polym. 38 (1998), pp. 219–226. G. Meyer, S.O. Fekete, and G.R. Wicker, Selective extraction of iron and aluminium from acidic solution, Patent 4,233,273, USA, 1980. G.P. Demopoulos, Iron(III) removal from base-metal electrolyte solutions by solvent extraction, Hydrometallurgy 12 (1984), pp. 299–315. R.K. Biswas and D.A. Begum, Solvent extraction of Fe3+ from chloride solution by D2EHPA in kerosene, Hydrometallurgy 50 (1998), pp. 153–168. D. Mohapatra, H.I. Kim, C.W. Nam, and K.H. Park, Liquid– liquid extraction of aluminium(III) from mixed sulphate solutions using sodium salts of Cyanex 272 and D2EHPA, Sep. Purif. Technol. 56 (2007), pp. 311–318. F.Q. Guo, S. Nishihama, and K. Yoshizuka, Selective recovery of copper, cobalt and nickel from aqueous chloride medium using solvent impregnated resin, Solv. Extr. Ion Exch., (2012), in press. doi: 10.1080/07366299.2012. 671114. K. Onishi, T. Nakamura, S. Nishihama, and K. Yoshizuka, Synergistic solvent impregnated resin for adsorptive separation of lithium ion, Ind. Eng. Chem. Res. 49 (2010), pp. 6554–6558. A.W. Trochimczuk, N. Kabay, M. Arda, and M. Streat, Stabilization of solvent impregnated resins (SIRs) by coating with water soluble polymers and chemical crosslinking, React. Funct. Polym. 59 (2004), pp. 1–7. K. Sarangi, B.R. Reddy, and R.P. Das, Extraction studies of cobalt (II) and nickel (II) from chloride solutions using NaCyanex 272. Separation of Co(II)/Ni(II) by the sodium salts of D2EHPA, PC-88A and Cyanex 272 and their mixtures, Hydrometallurgy 52 (1999), pp. 253–265. M. Dogan, H. Abak, and M. Alkan, Adsorption of methylene blue onto hazelnut shell: Kinetics, mechanism and activation parameters, J. Hazard. Mater. 164 (2009), pp. 172–181. B.C. Pan, Q.X. Zhang, F.W. Meng, X.T. Li, X. Zhang, and J.Z. Zheng, Sorption enhancement of aromatic sulfonates onto an aminated hyper-cross-linked polymer, Environ. Sci. Technol. 39 (2005), pp. 3308–3313.
Appendix Breakthrough capacity is defined as the capacity of column at the time where unadsorbed metal ion begins to be emitted. Total capacity of resin, qc (mmol), is defined as the total amount of adsorbed metal ion calculated from adsorption isotherms: qc = qmax mSIR
(A1)
where qmax is the maximum adsorption capacity (mmol/g) determined from Langmuir adsorption isotherms, and mSIR is the mass of SIR packed in the column (g). Elution efficiency is defined as the fraction of eluted metal ion of the initial metal ion loaded on the column at the time of elution, usually given as a percentage: Elution efficiency (%) =
Meluted × 100 Minitial
(A2)
Environmental Technology where Meluted is the amount of metal ion eluted from the column (mmol), and Minitial is the amount of metal ion initially loaded on the column (mmol). Utilization rate of SIR is defined as the percentage of the extractant impregnated in SIR used to capture metal
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ions:
qa × 100 (A3) qc where qa is the total amount of metal ion adsorbed onto resin (mmol), and qc is the total capacity of resin (mmol). Utilization rate of SIR(%) =
Selective recovery of valuable metals from spent Li-ion batteries using solvent-impregnated resins Fuqiang Guo, Syouhei Nishihama and Kazuharu Yoshizuka∗ Department of Chemical Engineering, The University of Kitakyushu, Kitakyushu, Japan (Received 17 April 2012; final version received 30 October 2012 ) Selective recovery of valuable metals (Cu2+ , Co2+ and Li+ ) from leachate of spent lithium-ion (Li-ion) batteries was investigated in acidic chloride media using solvent impregnated resins (SIRs). An SIR containing bis(2-ethylhexyl) phosphoric acid (D2EHPA) had high selectivity for Fe3+ and Al3+ , with an order of selectivity Fe3+ > Al3+ > Cu2+ > Co2+ . Fe3+ and Al3+ could be removed from synthetic leachate by precipitation, followed by column adsorption with the SIR containing D2EHPA. The synthetic leachate was then applied to chromatography for selective recovery of Cu2+ , Co2+ and Li+ . The solution was first fed upward to a column packed with an SIR containing 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC-88A) for selective separation of Cu2+ , followed by upward feed to another column packed with an SIR comprising PC-88A and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) for selective recovery of Co2+ . Finally, a column packed with a synergistic SIR containing both 1-phenyl-1,3-tetradecanedione (C11 phβDK) and tri-n-octylphosphine oxide (TOPO) was used for selective recovery of Li+ . A process flowsheet is proposed for selective recovery of Cu2+ , Co2+ and Li+ using several SIRs. This process was found to be simple and efficient for selective recovery of valuable metals from leachate of spent Li-ion batteries. Pure copper, cobalt and lithium products were obtained, with high elution yields. Keywords: Li-ion battery; adsorption; recovery; solvent impregnated resins; PC-88A; Cyanex 272
1. Introduction Lithium-ion batteries (LIBs) are one of the most popular types of rechargeable cell, because they are light in weight, have high energy density, high battery voltage, no memory effect, a long charging-discharging cycle and operate over a wide temperature range [1–3]. Because of their excellent electrochemical properties, safety and acceptable environmental effects, LIBs have been widely used as electrochemical power sources in mobile telephones, laptop computers, video-cameras and other modern electronic equipment [4,5]. The annual global production and consumption of LIBs have been rapidly rising. However, their inappropriate disposal may cause environmental concerns because of the generation of hazardous waste from flammable and toxic elements or compounds, even though spent LIBs are not generally classified as dangerous waste [6,7]. Recycling of spent LIBs has increasingly become an important issue faced by many countries. Simultaneously, spent LIBs are considered as secondary resources or the so-called ‘urban mine’ and economic benefits could be achieved in recovery of major components from spent LIBs [8,9]. Some of the metals in LIBs can be found at higher concentration levels than those typically found in processing concentrates of natural ores or natural ores themselves [10]. The recovery of valuable metals from spent LIBs is ∗ Corresponding
author. Email: [email protected]
© 2013 Taylor & Francis
thus highly desirable for protecting natural resources and the environment either at the present time or in the near future. Various processes have been reported for separation or recovery of metals from spent LIBs and these can be classified into two general categories: physical and chemical processes. Several of the existing processes for recycling LIBs use various types of thermal treatment, while others are fully mechanical. Most processes are focused on cobalt recovery but do not recover lithium as a refined product. Solvent extraction, an effective chemical technology, has been applied to the recovery of metals from spent LIBs, because of its simple operation, inexpensive equipment and the easy recovery and recycle of the solvents. In a joint recycling venture between Sony and Sumitomo Metal Mining in Ehime, Japan, standard hydrometallurgical methods are used to recover cobalt from active cathode materials after untreated LIBs are incinerated at 1000°C, while lithium is not a target for recovery [11]. Zhang et al. reported a hydrometallurgical process for separation and recovery of cobalt and lithium from spent LIBs [12]. It was found that solvent extraction with 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC-88A) was quite effective in separating cobalt from lithium to obtain highpurity cobalt product. A reductive leaching and solvent extraction
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process using bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) was developed for recovery of cobalt sulphate from spent LIBs by Kang et al. [13]. After reductive leaching and removal of metal ion impurities such as copper, iron and aluminium, cobalt was selectively extracted from the purified aqueous phase with 50% saponified 0.4 mol/L Cyanex 272. Overall, 92% cobalt could be recovered from spent LIBs. Dorella et al. investigated a hydrometallurgical route consisting of the following steps, focusing on recovery of cobalt from spent LIBs: (1) manual dismantling, (2) manual separation of anode/cathode, (3) leaching with sulphuric acid in an oxidizing environment, (4) precipitation with NH4 OH and (5) solvent extraction with Cyanex 272, to separate cobalt from lithium [14]. Nan et al. reported a recycling process for valuable metal from spent LIBs using chemical deposition and solvent extraction [15]. The mass cobalt was chemically deposited as oxalate; and 5-nonylsalicylaldoxime (Acorga M 5640) and Cyanex 272 were efficient and selective for extraction of copper and cobalt in sulphate solution. A mixed extractant system was developed for the separation and purification of cobalt and lithium from spent LIB leach solutions by Cheng et al. [16] A process flowsheet has been proposed for recovering cobalt and lithium from spent lithium-ion battery leach solutions using the mixed Ionquest 801 and Acorga M5640 system in the first solvent extraction circuit and Cyanex 272 in the second solvent extraction circuit. The solvent extraction technology thus provides an exciting opportunity for the recycling of spent LIBs. Recently, disadvantages of the solvent extraction method, such as the intense mixing of phases, the requirement for large amounts of organic solvent, the third phase formation and the loss of organic solvent into the aqueous phase, have been pointed out. Therefore, there is intense interest in creating a technology combining the advantages of solvent extraction with those of adsorption and/or ion exchange. Solvent impregnated resins (SIRs) [17–21] and microcapsules encapsulating extractant [22–25] have been investigated as a second-generation extraction system. SIRs are easily prepared by treating a polymer resin with an organic solvent containing extractants, and has been shown to produce effective adsorbents for selective separation and removal of metals, even at low concentrations. Akita and Takeuchi conducted the adsorption of Zn2+ , Cu2+ , Co2+ and Ni2+ using SIRs containing bis(2-ethylhexyl) phosphoric acid (D2EHPA) and PC-88A to attain the selective separation of Zn2+ /Cu2+ and Co2+ /Ni2+ [26]. Levextrel resin (a microcapsule resin) containing Cyanex 272 was applied for the adsorptive separation of Co2+ and Ni2+ from aqueous ammonium nitrate and sulphate solutions by Yoshizuka et al. [27]. Kabay et al. investigated the extraction of Cd2+ and Cu2+ from phosphoric acid with SIRs containing bis(2,4,4-trimethylpentyl) monothiophosphinic acid (Cyanex 302) [28]. The separation of Cd2+ , Fe3+ and Ni2+ using SIRs containing Cyanex 272 and Cyanex 302 was investigated by Gonzalez et al. [18]. SIRs impregnated
with acidic organophosphorus extractants are feasible for separating or recovering a number of metal ions from industrial toxic sludges, metal-bearing wastewater and various secondary resources. Acidic organophosphorus extractants were recommended by Meyer et al. for selective extraction of iron and aluminium from acidic solution [29]. D2EHPA was reported to be an effective extractant for extracting Fe3+ and Al3+ from aqueous solution [30–32] and is normally used for removal of Fe3+ and Al3+ to attain desired purity of metals in hydrometallurgical processing operations. In previous work, it was found that an SIR containing PC-88A had high selectivity for Cu2+ and the order of selectivity was Cu2+ > Co2+ > Ni2+ [33]. Moreover, the adsorption of Co2+ and Ni2+ could be significantly suppressed by the high selectivity for Cu2+ of a PC-88A SIR in Cu2+ , Co2+ and Ni2+ ternary metal systems. The separation of Cu2+ from co-existing Co2+ and Ni2+ can be achieved with a PC-88A SIR by controlling the pH of the aqueous solution. In previous work, high selectivity for Co2+ was observed using an SIR containing Cyanex 272, and Co2+ could be effectively separated from binary metal solutions containing Co2+ and Ni2+ by chromatographic operation [33]. The adsorptive separation of Li+ with a synergistic SIR impregnated with both 1-phenyl-1,3-tetradecanedione (C11 phβDK) and trin-octylphosphine oxide (TOPO) was also investigated in aqueous chloride media in previous work [34], showing high selectivity for Li+ over Na+ and K+ . Li+ could thus be effectively separated from aqueous solution containing a large excess of Na+ concentration by chromatographic operation. In this study, a recycling process for selective recovery of valuable metals (Cu2+ , Co2+ and Li+ ) from synthetic leachate of spent LIBs by solvent impregnated resins (SIRs) was investigated. SIRs impregnated with 3 types of acidic organophosphorus extractants were applied not only to remove Fe3+ and Al3+ , but also to recover Cu2+ and Co2+ . Selective recovery of Li+ could be achieved by using an SIR containing both C11 phβDK and TOPO. A recycling process flowsheet is proposed for mutual recovery of Cu2+ , Co2+ and Li+ from spent LIBs using SIRs. 2. Experimental 2.1. Materials A synthetic leachate containing 133.1 mmol/L Cu2+ , 358.0 mmol/L Co2+ , 353.0 mmol/L Li+ , 135.2 mmol/L Al3+ and 1.1 mmol/L Fe3+ was prepared by dissolving the corresponding metal chlorides in hydrochloric acid solution. The composition of the synthetic leachate was analogous with that of leachate from a spent Li-ion battery (Panasonic CGR18650H type) with a cylindrical shape from a laptop computer, as described previously [33]. DIAION HP2MG, a methacrylic ester copolymer, was kindly supplied by Nippon Rensui Co., Ltd and used as a polymer support for preparing SIRs. The structure of
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(a) 300 250
[Mx+] (mmol/L)
200 150 100
Cu2+ Co2+ Li+ Fe3+ Al3+
10 5 0 0
2
4
6
8
10
12
14
16
18
Bed volume (-)
(b) 160 140
[Mx+] (mmol/L)
120 100 80
Cu2+ Co2+ Li+ Fe3+ Al3+
60 40 20 0 0
1
2
3
4
5
6
Bed volume (-) Figure 1. (a) Breakthrough and (b) elution profiles for Fe3+ and Al3+ with D2EHPA SIR. pH = 2.66, [Cu2+ ]feed = 96.5 mmol/L, [Co2+ ]feed = 257.6 mmol/L, [Al3+ ]feed = 13.0 mmol/L, [Fe3+ ]feed = 0.04 mmol/L, [Li+ ]feed =249.0 mmol/L. Flow rate = 0.1 mL/ min. Breakthrough BV for Al3+ = 11.3, breakthrough BV for Fe3+ = 2. Breakthrough capacity for Al3+ = 4.84 mmol, breakthrough capacity for Fe3+ = 0.003 mmol. Total capacity of resin for Al3+ = 6.40 mmol, total capacity of resin for Fe3+ = 6.00 mmol. Elution efficiency for Al3+ = 61.4%, elution efficiency for Fe3+ = 87.8. Utilization rate of SIR for Al3+ = 75.8%, utilization rate of SIR for Fe3+ = 0.3%.
HP2MG is shown in Figure S1 (See Appendix), and its particle size distribution ranges from 25 to 50 mesh (>90%). The specific surface area, pore volume and pore radius of HP2MG are reported by the manufacturer to be 570 m2 /g, 1.3 mL/g and 24 nm, respectively. The commercial extractants used were D2EHPA, PC88A and Cyanex 272, supplied by Nacalai Tesque, Inc., Daihachi Chemical Industry and Nihon Cytec Industries
Inc., respectively. TOPO was supplied by Tokyo Chemical Industry. All other organic and inorganic reagents were analytical grade and supplied by Wako Pure Chemistry Industries. All reagents were utilized as received, without further purification. C11 phβDK was synthesized according to the procedure reported in a previous paper [34]. The product was identified by a proton nuclear magnetic resonance
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spectrometer (1 HNMR, JEOL JMM-ECP500), a Fourier transform infrared spectrophotometer (FTIR, Shimadzu FTIR-8400S) and an Elementary Analyzer (Yanaco, MT6 Corder). The results were as follows: C, 79.26; H, 9.87%. Calculated for C20 H30 O2 : C, 79.42; H, 10.00%. 2.2.
ions in the aqueous solutions were analyzed by an inductively coupled plasma atomic emission spectrometer (ICPAES, Shimadzu ICPS-7000), to determine the corresponding adsorption amounts at equilibrium, qM (mmol/g). qM was calculated from the difference in metal concentration in the aqueous phase before and after adsorption as follows:
Preparation of SIR
SIRs containing D2EHPA, PC-88A, Cyanex 272 or C11 phβDK and TOPO were prepared by the following method [33,34]. HP2MG was washed with methanol and dried in vacuo. The washed resin was immersed overnight in a toluene solution containing D2EHPA, PC-88A, Cyanex 272 or C11 phβDK and TOPO. The toluene was then removed by evaporation and the resin was dried in vacuo for 24 h. The amount of the extractant impregnated in the resin was determined by the difference in weight before and after impregnation. The amounts of D2EHPA and PC88A impregnated in the resins were 1.22 and 1.24 mmol/g, respectively. The SIR containing PC-88A and Cyanex 272 with a mole ratio of PC-88A/Cyanex 272 = 5/1 was also prepared with 1.01 mmol/g of PC-88A and 0.19 mmol/g of Cyanex 272. SIRs used for adsorption of Li+ were impregnated with 0.66 mmol/g of both C11 phβDK and TOPO. The SIRs containing D2EHPA, PC-88A and Cyanex 272 were coated with a hydrophilic polymer to prevent leakage of the extractant [21,33,35]. The coating agent was prepared by dissolving 3 g of polyvinyl alcohol (PVA, polymerization degree = ca. 2000) and 1 g of acetamide in 96 g of de-ionized water under heating and magnetic stirring. In a typical procedure, 3 g of vacuum-dried SIR was immersed in 50 mL of PVA solution and shaken for 17 h. Then, 10 mL of 1 mol/L KCl solution was added and shaken for 24 h. The SIR was filtered off from the solution and re-suspended in 10 mL of 0.32 mol/L H2 SO4 . 10 mL of 0.32 mol/L glutaraldehyde solution was then added to the suspended solution and shaken for 24 h. Finally, the SIR was filtered, washed with a large excess of de-ionized water and dried in vacuo. The SIR containing C11 phβDK and TOPO was not coated but was simply treated with an aqueous solution of 0.1 wt% sodium lauryl sulphate to make the surface of the resin hydrophilic prior to chromatographic operation. 2.3. Batchwise adsorption of metal ions Aqueous solutions of metal ions were prepared by dissolving the corresponding metal chlorides in hydrochloric acid solution. The concentration of each metal ion for pH dependence experiments was set to 1.0 mmol/L. 20 mg of SIR was added to 10 mL of aqueous solution. The pH was adjusted by adding an appropriate amount of hydrochloric acid or sodium hydroxide to the aqueous solution. The mixture was shaken vigorously at 298 K for more than 12 h to attain equilibrium. After filtration, the equilibrium pH was measured by a pH meter (Horiba F-23). The concentration of metal
qM =
([M]initial − [M]) · L w
(1)
where [M]initial (mmol/L) and [M] (mmol/L) are the initial and equilibrium concentrations of metal ion in the aqueous phase, respectively, L (L) is the volume of aqueous solution and w (g) is the weight of SIR. 2.4.
Chromatographic operation for metal recovery
A sample of 20.0 g of SIR (wet volume = 40.0 mL) was packed into a column 20 mm in diameter and washed with de-ionized water. The aqueous feed solution to SIR was fed upward through the column at a flow rate of 0.1 mL/min (space velocity (SV) = 0.15 h−1 ), using a dualplunger pump (EYELA, KP-11). The pH of the aqueous feed solution was adjusted by adding an appropriate amount of hydrochloric acid or sodium hydroxide to the aqueous solution. In some cases, sodium acetate/acetic acid buffer solution was used. After breakthrough of metal ions, de-ionized water was fed into the column to wash out residual feed solution. The loaded metal ions were then eluted with 1.0 mol/L HCl solution. The effluents were collected with a fraction collector (EYELA, DC-1500). The pH values and metal concentrations were determined by a pH meter and ICP-AES or an atomic absorption spectrometer (AAS, Shimadzu AAS-6800), respectively. Bed volume (BV) of the effluent is defined as BV =
vt V
(2)
where v (mL/min), t(min) and V (mL) are the flow rate of solution, the time for which feed solution was supplied and the wet volume of adsorbent, respectively. 3. Results and discussion 3.1. Removal of Fe3+ and Al3+ 3.1.1. Removal of Fe3+ and Al3+ by chemical precipitation Chemical precipitation with NaOH was used to remove Fe3+ and Al3+ from synthetic leachate. The concentration of metal ions in synthetic leachate before and after precipitation is listed in Table 1. Over 90% of Fe3+ and 85% of Al3+ were removed as their hydroxides by adjusting pH to 4.1 with 1.0 mol/L NaOH. The total losses of Co2+ and Li+ were 1.3% and 3.1%, respectively. Although ca. 3.3% of Cu2+ was lost, the loss of metal ions is attributed to a
Environmental Technology Table 1. Metal concentrations in the synthetic leachate before and after precipitation. Li Initial concentration∗ (mmol/L) Concentration at pH 4.1† (mmol/L) Loss‡ (%)
Cu
Co
Al
Fe
353.0 133.1 358.0 135.2
1.1
341.9 128.7 353.5
19.1
0.1
85.9
90.9
3.1
3.3
1.3
∗ Metal
concentrations in synthetic leachate [33]. concentrations after adjusting the pH to 4.1 with 1.0 mol/L NaOH solution. ‡ Percentage metal loss from synthetic leachate to the residue, based on mass balance. † Metal
too high local concentration of OH− in synthetic leachate or incorporation with hydroxide solids during precipitation. The small amount of residual Fe3+ and Al3+ in the solution would be removed by column adsorption with the D2EHPA SIR. 3.1.2. Complete removal of Fe3+ and Al3+ by chromatographic operation with the D2EHPA SIR After chemical precipitation of Fe3+ and Al3+ , small amounts of Fe3+ and Al3+ remained in the solution, so D2EHPA SIR was used to remove them. The effect of equilibrium pH on the amounts of metal ions adsorbed from single metal systems is shown in Figure S2. The characteristic curves are similar to one another, exhibiting strong dependence of metal ion adsorption behaviour on pH. The adsorption ability of the D2EHPA SIR for the metal ions followed the order: Fe3+ > Al3+ > Cu2+ > Co2+ . Fe3+ and Al3+ were strongly adsorbed when pH was around 2.0 and 2.6, respectively, while Cu2+ and Co2+ were hardly adsorbed. Therefore, through pH control, the D2EHPA SIR could be used for the complete removal of Fe3+ and Al3+ from an aqueous solution also containing Cu2+ and Co2+ . Based on batchwise experiments, the chromatographic separation of Fe3+ and Al3+ from synthetic aqueous solution (after removal of Fe3+ and Al3+ by chemical precipitation) was conducted using the D2EHPA SIR. Figure 1(a) shows the breakthrough profiles for Fe3+ and Al3+ . Fe3+ and Al3+ were selectively adsorbed, while Cu2+ , Co2+ and Li+ were scarcely adsorbed. As shown in the elution profiles in Figure 1(b), Fe3+ and Al3+ were quantitatively eluted by 1.0 mol/L HCl solution, while Cu2+ , Co2+ and Li+ were not eluted. Therefore, the complete removal of Fe3+ and Al3+ from the aqueous solution was achieved using the D2EHPA SIR. The effluent collected before the breakthrough of Fe3+ and Al3+ was used for the recovery of valuable metals as described below. 3.2. Separation and recovery of Cu2+ After complete removal of Al3+ and Fe3+ , Cu2+ , Co2+ and Li+ remained in the aqueous solution. The concentrations
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of metals in the aqueous solution are shown in Table 2. A PC-88A SIR was used first for selective recovery of Cu2+ from the aqueous solution. Chromatographic separation of Cu2+ from the aqueous solution after removal of Al3+ and Fe3+ was conducted using the PC-88A SIR. Figure 2(a) shows the breakthrough profiles of Cu2+ , Co2+ and Li+ . Cu2+ was selectively adsorbed, while Li+ was scarcely adsorbed. A small amount of Co2+ was adsorbed in the column before the breakthrough of Cu2+ . Figure 2(b) shows the elution profiles for Cu2+ , Co2+ and Li+ with 1.0 mol/L HCl solution. Cu2+ was quantitatively eluted with an elution yield of greater than 94%, while no Li+ was eluted. The maximum concentration of Cu2+ reached 150 mmol/L. Although the adsorbed Co2+ primarily loaded in the column could be replaced by competing Cu2+ , as shown in Figure 2(a), little Co2+ remained in the column. This Co2+ fraction may be eluted together with Cu2+ , resulting in a loss of metal. Because Cu2+ has a much higher concentration than Co2+ in the eluent, the adsorption of Co2+ could be markedly suppressed by the high selectivity for Cu2+ of the PC-88A SIR. The fraction of Co2+ in the eluent could be separated and recovered by passing the eluent through a column packed with PC-88A SIR. Figure S3 shows the breakthrough and elution profiles for Cu2+ separation and purification from an eluent with the PC-88A SIR. Cu2+ was selectively adsorbed, while Co2+ was scarcely adsorbed. The effluent collected before breakthrough of Cu2+ contained only Co2+ enabling its recovery, as shown in the elution profiles for Cu2+ and Co2+ with 1.0 mol/L HCl solution. Cu2+ was quantitatively eluted with a high purity of ca. 100% at BV = 1.5, while little Co2+ was eluted. The maximum concentration of Cu2+ was 178 mmol/L. 3.3.
Recovery of Co2+
Although the SIR containing Cyanex 272 exhibited excellent selectivity for Co2+ over Ni2+ [33], Cyanex 272 is more expensive than PC-88A. Because Ni2+ in the leachate of spent LIBs comes mainly from the steel shell, the concentration of Ni2+ is much lower than that of Co2+ . Therefore, a SIR containing both PC-88A and Cyanex 272 was used to recover Co2+ from the aqueous solution. Figure S4 shows the effect of pH on the amounts of metal ions adsorbed by SIRs with different ratios of PC88A/Cyanex 272 in a binary system of Co2+ and Ni2+ . The adsorption behaviours were almost the same for all PC-88A/Cyanex 272 ratios. At pH < 4.3, the amount of Co2+ adsorbed by the PC-88A/Cyanex 272 SIR increased with increasing PC-88A/Cyanex 272 ratio in the order: 1/5 < 1/2 < 1/1 < 5/1. The synergistic effect is distinct in the case of the 5/1 PC-88A/Cyanex 272 ratio SIR, in agreement with those in solvent extraction systems [36]. The adsorption of Ni2+ is markedly suppressed by high Co2+ selectivity.
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(a) 300
[Mx+] (mmol/L)
250
Co2+ Li+ Cu2+
200
150 100 50
0 0
1
2
3
4
5
Bed volume (-)
(b)
[Mx+] (mmol/L)
150
100
Cu2+ Co2+ Li+
50
0 0
1
2
3
4
5
Bed volume (-) Figure 2. (a) Breakthrough and (b) elution profiles for Cu2+ with PC-88A SIR. pH = 4.19, [Cu2+ ]feed = 94.5 mmol, [Co2+ ]feed = 257.3 mmol, [Li+ ]feed = 247.1 mmol. Flow rate = 0.1 mL/min. Breakthrough BV for Cu2+ = 2.1, breakthrough BV for Co2+ = 0.1. Breakthrough capacity for Cu2+ = 7.97 mmol, breakthrough capacity for Co2+ = 1.03 mmol. Total capacity of resin for Cu2+ = 8.40 mmol, total capacity of resin for Co2+ = 7.00 mmol. Elution efficiency for Cu2+ = 94.7%, elution efficiency for Co2+ = 53.7%. Utilization rate of SIR for Cu2+ = 101.7%, utilization rate of SIR for Co2+ = 74.7%.
A column packed with a 5/1 PC-88A/Cyanex 272 ratio SIR was used for the chromatographic separation of Co2+ from the aqueous solution after recovering Cu2+ . The breakthrough profiles for Co2+ and Li+ on the column are shown in Figure 3(a). The breakthrough point was around BV = 1.2, after which the concentration of Co2+ in the effluent rapidly increased. Co2+ was selectively adsorbed, while Li+ was scarcely adsorbed. The excess
concentrations on the breakthrough curves for Li+ were caused by the displacement effects of the competing Co2+ . An aliquot fraction of Li+ previously loaded on the column can be replaced by Co2+ when insufficient adsorption sites are available [37,38]. The column was then eluted with 1.0 mol/L HCl solution after the adsorption process was completed. As shown in the elution profiles of Co2+ and Li+ in Figure 3(b), Co2+ was quantitatively eluted to
Environmental Technology
3.4. Recovery of Li+ After recovery of Cu2+ and Co2+ , only the alkali metals, Li+ and Na+ , remained in the aqueous solution. The concentration of Na+ was much higher than that of Li+ because a large amount of NaOH was added into the solution to adjust the pH. Therefore, an SIR containing C11 phβDK and TOPO was used to recover Li+ from the aqueous solution after chromatographic recovery of Cu2+ and Co2+ . Figure S5 shows the breakthrough profiles for Li+ from the aqueous solution with the C11 phβDK/TOPO SIR. Li+
Table 2. Metal concentrations in the synthetic aqueous solution used for chromatographic operation with PC-88A SIR.
Concentration (mmol/L)
Cu
Co
Li
Al
Fe
94.5
257.3
247.1
0
0
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obtain a high purity of almost 100% at BV = 1.4, while no Li+ was eluted. The maximum concentration of Co2+ was 223 mmol/L.
(a) 300
[Mx+] (mmol/L)
250 200 150 100
Co2+ Li+
50 0 0.0
0.5
1.0
1.5
2.0
2.5
Bed volume (-)
(b) 250
x+
[M ] (mmol/L)
200
150
100
Co2+ Li+
50
0 0
1
2
3
4
5
6
7
Bed volume (-) Figure 3. (a) Breakthrough and (b) elution profiles for with PC-88A/Cyanex 272 SIR. pH = 5.17, [Co2+ ]feed = 244.1 mmol/L, [Li+ ]feed = 243.7 mmol/L. Flow rate = 0.1 mL/min. Breakthrough BV for Co2+ = 1.2. Breakthrough capacity for Co2+ = 8.79 mmol. Total capacity of resin for Co2+ = 9.49 mmol. Elution efficiency for Co2+ = 93.1%. Utilization rate of SIR for Co2+ = 94.9%. Co2+
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F. Guo et al.
(a) 4000 3500 3000
+
[M ] (mmol/L)
2500 2000 1500 1000
Li+ Na+
400 300 200 100 0 0
1
2
3
4
Bed volume (-)
(b) 500
300
200
+
[M ] (mmol/L)
400
Li+ Na+
100
0 0
1
2
3
4
Bed volume (-) Figure 4. (a) Breakthrough and (b) elution profiles for with C11 phβDK/TOPO SIR. pH = 12.29, [Li+ ]feed = 234.0 mmol/L, [Na+ ]feed = 3529.2 mmol/L. Flow rate = 0.1 mL/min. Breakthrough BV for Li+ = 0.8. Breakthrough capacity for Li+ = 7.49 mmol. Total capacity of resin for Li+ = 14.82 mmol. Elution efficiency for Li+ = 93.9%. Utilization rate of SIR for Li+ = 123.5%. Li+
was selectively adsorbed, while Na+ was scarcely adsorbed. Figure 4(b) shows the elution profiles for Li+ and Na+ with 1.0 mol/L HCl solution. Li+ was quantitatively eluted with a high purity of almost 100% at BV = 1.5, while no Na+ was eluted. The elution yield of Li+ was more than 93% and the maximum concentration of Li+ was 441 mmol/L. 3.5. Reusability of SIRs To apply the SIRs to chromatographic separation and recovery on an industrial scale, the reusability of the SIRs
is important. The reuse performances of SIRs were examined. Figure 5 shows the breakthrough and elution profiles of Co2+ and Li+ using the PC-88A/Cyanex 272 SIR. The adsorption-elution process cycle was conducted five times with the same column. The breakthrough profiles for the first and fifth cycles indicated no decline in adsorption-elution profile and the elution profiles during the five cycles were essentially the same as those in Figure 3(b). This indicates that the PC-88A/Cyanex 272 SIR is suitable for column operation as well, as it has sufficient loading capacity for use in repeated processing. The reusability and stability of
Environmental Technology Spent Li-ion batteries
Dismantling of case 2 mol/L HCl, 70°C, 5 h Leachate Cu2+, Co2+, Li+, Al3+, Fe3+, pH 4.1 Removal of Al and Fe 2+
Al(OH)3, Fe(OH)3 2+
+
Cu , Co , Li , little Al3+, Fe3+, pH 2.6
2+
+
D2EHPA SIR
Al, Fe
2+
Cu , Co , Li , pH 4.2 PC-88A SIR 2+
Cu +
Co , Li , pH 5.2 PC-88A/Cyanex272 SIR
Co
Li+, pH 12.3 C11
/TOPO SIR
Li
Figure 5. A process flowsheet for recovery of valuable metals from spent Li-ion batteries using SIRs.
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4. Conclusions The selective recovery of valuable metals (Cu2+ , Co2+ , Li+ ) from the leachate of spent LIBs by SIRs was investigated in acidic chloride media. A D2EHPA SIR has high selectivity for Fe3+ and Al3+ , with selectivity in the order Fe3+ > Al3+ > Cu2+ > Co2+ . Fe3+ and Al3+ could be easily removed from the aqueous solution by chemical precipitation, followed by chromatographic separation with D2EHPA SIR. The separation and recovery of Cu2+ from the aqueous solution could be achieved using a PC88A SIR. A high selectivity for Co2+ was observed with a PC-88A/Cyanex 272 SIR, enabling effective chromatographic separation of Co2+ . Finally, a C11 phβDK/TOPO SIR was used for selective recovery of Li+ . Thus, the selective recovery of Cu2+ , Co2+ and Li+ from the leachate of spent LIBs was achieved via one chemical precipitation and four chromatographic operations. A process flowsheet was then proposed for recovery of Cu2+ , Co2+ and Li+ using SIRs. Acknowledgements We are grateful for financial support through a Grant-in-Aid for Scientific Research (No. K2127, K22091 and K2340) from the Ministry of Environment of Japan.
the other SIRs used in this study were confirmed in previous works [33,34].
References
Process flowsheet for selective recovery of Cu2+ , Co2+ and Li+ from spent LIBs A process flowsheet for selective recovery of Cu2+ , Co2+ and Li+ from spent LIBs using several SIRs is proposed here, as shown in Figure 5. During the procedures of dismantling and acid leaching of spent LIBs, the isolation of anode and cathode materials from the copper foil and aluminium foil is unnecessary. Both anode and cathode films are leached by HCl solution. Most of the iron and aluminium is removed by adjusting the pH of the leachate. The small amounts of Al3+ and Fe3+ remaining in solution are removed by the first chromatographic operation with the D2EHPA SIR, and the effluent contains copper, cobalt and lithium. In the second chromatographic operation, using the PC-88A SIR, copper is recovered by adsorption on the column and the effluent contains cobalt and lithium. Cobalt could be completely separated from lithium after the effluent is fed through the third chromatographic operation using the PC-88A/Cyanex 272 SIR. Finally, the C11 phβDK/TOPO SIR can be used to recover lithium. Compared with solvent extraction, chromatographic operation using SIRs does not require intensive mixing of phases, multistage cycles of extraction and striping or large amounts of organic solvent. The main advantage of the proposed process is the simplification of the recycling process for spent LIBs.
[1] E. Plichta, M. Salomon, S. Slane, M. Uchiyama, D. Chua, W.B. Ebner, and H.W. Lin, A rechargeable Li/Lix CoO2 Cell, J. Power Sources 21 (1987), pp. 25–31. [2] C.M. Sabin, Battery paste recycling process, Patent 5,690,718, USA, 1997. [3] A. Lundblad and B. Bergman, Synthesis of LiCoO2 starting from carbonate precursors II. Influence of calcination conditions and leaching, Solid State Ionics 96 (1997), pp. 183– 193. [4] J. Nan, D. Han, and X. Zuo, Recovery of metal values from spent lithium-ion batteries with chemical deposition and solvent extraction, J. Power Sources 152 (2005), pp. 278–284. [5] D.I. Ra and K.S. Han, Used lithium ion rechargeable battery recycling using Etoile-Rebatt technology, J. Power Sources 163 (2006), pp 284–288. [6] S. Castillo, F. Ansart, C. Laberty-Robert, and J. Portal, Advance in the recovering of spent lithium battery compounds, J. Power Sources 112 (2002), pp. 247–254. [7] J.C. Alfonso, N.G. Busnardo, and R.G. Busnardo, Global Symposium on Recycling, Waste Treatment and Clean Technology, in Proceedings of REWAS 2004, Vol. III, I. Gaballah, B. Mishra, R. Solozobal and M. Tanaka, eds., TMS, Warrendale, Pennsylvania, USA, 2004, pp. 2783– 2785. [8] B.R. Conard, The role of hydrometallurgy in achieving sustainable development, Hydrometallurgy 30 (1992), pp. 1–28. [9] J.Q. Xu, H.R. Thomas, R.W. Francis, K.R. Lum, J.W. Wang, and B. Liang, A review of processes and technologies for the recycling of lithium-ion secondary batteries, J. Power Sources 177 (2008), pp. 512–527. [10] G. Dorella and M. B. Mansur, A study of the separation of cobalt from spent Li-ion battery residues, J. Power Sources 170 (2007), pp. 210–215.
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[11] M.J. Lain, Recycling of lithium ion cells and batteries, J. Power Sources 97–98 (2001), pp. 736–738. [12] P.W. Zhang, T. Yokoyama, O. Itabashi, T.M. Suzuki, and K.Inoue, Hydrometallurgical process for recovery of metal values from spent lithium-ion secondary batteries, Hydrometallurgy 47 (1998), pp. 259–271. [13] J. Kang, G. Senanayake, J. Sohn, and S.M. Shin, Recovery of cobalt sulfate from spent lithium ion batteries by reductive leaching and solvent extraction with Cyanex 271, Hydrometallurgy 100 (2010), pp. 168–171. [14] G. Dorella and M.B. Mansur, A study of the separation of cobalt from spent Li-ion battery residues, J. Power Sources 170 (2007), pp. 210–215. [15] J.M. Nan, D.M. Han, and X.X. Zuo, Recovery of metal values from spent lithium-ion batteries with chemical deposition and solvent extraction, J. Power Sources 170 (2007), pp. 210–215. [16] Y. Pranolo, W. Zhang, and C.Y. Cheng, Recovery of metals from spent lithium-ion battery leach solutions with a mixed solvent extraction system, Hydrometallurgy 102 (2010), pp. 37–42. [17] R.S. Juang and M.L. Chen, Application of the Elovich equation to the kinetics of metal sorption with solventimpregnated resins, Ind. Eng. Chem. Res. 36 (1997), pp. 813–820. [18] M.P. Gonzalez, I. Saucedo, R. Navarro, M. Avila, and E. Guibal, Selective separation of Fe(III), Cd(II), and Ni(II) from dilute solutions using solvent-impregnated resins, Ind. Eng. Chem. Res. 40 (2001), pp. 6004– 6013. [19] C.Y. Shiau, C.L. Lin, and H.S. Chang, Adsorption equilibrium of zinc from aqueous sulfate solution by solventimpregnated resins containing Cyanex 272, Ind. Eng. Chem. Res. 44 (2005), pp. 4771–4777. [20] T. Nakamura, T. Ikawa, S. Nishihama, and K. Yoshizuka, Selective recovery of indium from acid sulfate media with solvent impregnated resin of bis(4-cyclohexylcyclohexyl) phosphoric acid as an extractant, Ion Exch. Lett. 2 (2009), pp. 22–26. [21] N. Kabay, J.L. Cortina, A. Trochimczuk, and M. Streat, Solvent-impregnated resins (SIRs) – Methods of preparation and their applications, React. Funct. Polym. 70 (2010), pp. 484–496. [22] E. Kamio and K. Kondo, Separation of rare metal ions by a column packed with microcapsules containing an extractant, Ind. Eng. Chem. Res. 41 (2002), pp. 3669– 3675. [23] S. Nishihama, G. Nishimura, T. Hirai, and I. Komasawa, Separation and recovery of Cr(VI) from simulated plating waste using microcapsules containing quaternary ammonium salt extractant and phosphoric acid extractant, Ind. Eng. Chem. Res. 43 (2004), pp. 751–757. [24] E. Kamio, M. Matsumoto, and K. Kondo, Theoretical development of metal extraction mechanism into an extractantimpregnated microcapsule, Ind. Eng. Chem. Res. 46 (2007), pp. 255–265. [25] X. Gong, Y. Lu, Z. Qian, and G. Luo, Preparation of uniform microcapsules containing 1-octanol for caprolactam extraction, Ind. Eng. Chem. Res. 48 (2009), pp. 4507–4513. [26] S. Akita and H. Takeuchi, Sorption and separation of divalent metals by a macromolecular resin containing organophosphorus acids, J. Chem. Eng. Data 37 (1992), pp. 303–306. [27] K. Yoshizuka, Y. Sakomoto, Y. Baba, and K. Inoue, Distribution equilibria in the adsorption of cobalt(II) and nickel(II)
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on Levextrel resin containing Cyanex 272, Hydrometallurgy 23 (1990), pp. 309–318. N. Kabay, M. Demircio˘glu, H. Ekinci, M. Yüksel, M. Sa˘glam, and M. Streat, Extraction of Cd(II) and Cu(II) from phosphoric acid solutions by solvent-impregnated resins (SIR) containing Cyanex 302, React. Funct. Polym. 38 (1998), pp. 219–226. G. Meyer, S.O. Fekete, and G.R. Wicker, Selective extraction of iron and aluminium from acidic solution, Patent 4,233,273, USA, 1980. G.P. Demopoulos, Iron(III) removal from base-metal electrolyte solutions by solvent extraction, Hydrometallurgy 12 (1984), pp. 299–315. R.K. Biswas and D.A. Begum, Solvent extraction of Fe3+ from chloride solution by D2EHPA in kerosene, Hydrometallurgy 50 (1998), pp. 153–168. D. Mohapatra, H.I. Kim, C.W. Nam, and K.H. Park, Liquid– liquid extraction of aluminium(III) from mixed sulphate solutions using sodium salts of Cyanex 272 and D2EHPA, Sep. Purif. Technol. 56 (2007), pp. 311–318. F.Q. Guo, S. Nishihama, and K. Yoshizuka, Selective recovery of copper, cobalt and nickel from aqueous chloride medium using solvent impregnated resin, Solv. Extr. Ion Exch., (2012), in press. doi: 10.1080/07366299.2012. 671114. K. Onishi, T. Nakamura, S. Nishihama, and K. Yoshizuka, Synergistic solvent impregnated resin for adsorptive separation of lithium ion, Ind. Eng. Chem. Res. 49 (2010), pp. 6554–6558. A.W. Trochimczuk, N. Kabay, M. Arda, and M. Streat, Stabilization of solvent impregnated resins (SIRs) by coating with water soluble polymers and chemical crosslinking, React. Funct. Polym. 59 (2004), pp. 1–7. K. Sarangi, B.R. Reddy, and R.P. Das, Extraction studies of cobalt (II) and nickel (II) from chloride solutions using NaCyanex 272. Separation of Co(II)/Ni(II) by the sodium salts of D2EHPA, PC-88A and Cyanex 272 and their mixtures, Hydrometallurgy 52 (1999), pp. 253–265. M. Dogan, H. Abak, and M. Alkan, Adsorption of methylene blue onto hazelnut shell: Kinetics, mechanism and activation parameters, J. Hazard. Mater. 164 (2009), pp. 172–181. B.C. Pan, Q.X. Zhang, F.W. Meng, X.T. Li, X. Zhang, and J.Z. Zheng, Sorption enhancement of aromatic sulfonates onto an aminated hyper-cross-linked polymer, Environ. Sci. Technol. 39 (2005), pp. 3308–3313.
Appendix Breakthrough capacity is defined as the capacity of column at the time where unadsorbed metal ion begins to be emitted. Total capacity of resin, qc (mmol), is defined as the total amount of adsorbed metal ion calculated from adsorption isotherms: qc = qmax mSIR
(A1)
where qmax is the maximum adsorption capacity (mmol/g) determined from Langmuir adsorption isotherms, and mSIR is the mass of SIR packed in the column (g). Elution efficiency is defined as the fraction of eluted metal ion of the initial metal ion loaded on the column at the time of elution, usually given as a percentage: Elution efficiency (%) =
Meluted × 100 Minitial
(A2)
Environmental Technology where Meluted is the amount of metal ion eluted from the column (mmol), and Minitial is the amount of metal ion initially loaded on the column (mmol). Utilization rate of SIR is defined as the percentage of the extractant impregnated in SIR used to capture metal
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ions:
qa × 100 (A3) qc where qa is the total amount of metal ion adsorbed onto resin (mmol), and qc is the total capacity of resin (mmol). Utilization rate of SIR(%) =
