This article was downloaded by: [University of Toronto Libraries] On: 22 December 2014, At: 08:26 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Environmental Technology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tent20
Removal of nickel and cadmium from battery waste by a chemical method using ferric sulphate a
Umesh U. Jadhav & Hong Hocheng
a
a
Department of Power Mechanical Engineering, National Tsing Hua University, No. 101, Sec.2, Kuang Fu Rd., 30013 Hsinchu, Taiwan, ROC Published online: 17 Dec 2013.
Click for updates To cite this article: Umesh U. Jadhav & Hong Hocheng (2014) Removal of nickel and cadmium from battery waste by a chemical method using ferric sulphate, Environmental Technology, 35:10, 1263-1268, DOI: 10.1080/09593330.2013.865791 To link to this article: http://dx.doi.org/10.1080/09593330.2013.865791
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Environmental Technology, 2014 Vol. 35, No. 10, 1263–1268, http://dx.doi.org/10.1080/09593330.2013.865791
Removal of nickel and cadmium from battery waste by a chemical method using ferric sulphate Umesh U. Jadhav and Hong Hocheng∗ Department of Power Mechanical Engineering, National Tsing Hua University, No. 101, Sec.2, Kuang Fu Rd., 30013 Hsinchu, Taiwan, ROC
Downloaded by [University of Toronto Libraries] at 08:26 22 December 2014
(Received 24 June 2013; accepted 9 November 2013 ) The removal of nickel (Ni) and cadmium (Cd) from spent batteries was studied by the chemical method. A novel leaching system using ferric sulphate hydrate was introduced to dissolve heavy metals in batteries. Ni–Cd batteries are classified as hazardous waste because Ni and Cd are suspected carcinogens. More efficient technologies are required to recover metals from spent batteries to minimize capital outlay, environmental impact and to respond to increased demand. The results obtained demonstrate that optimal conditions, including pH, concentration of ferric sulphate, shaking speed and temperature ◦ for the metal removal, were 2.5, 60 g/L, 150 rpm and 30 C, respectively. More than 88 (±0.9) and 84 (±2.8)% of nickel and cadmium were recovered, respectively. These results suggest that ferric ion oxidized Ni and Cd present in battery waste. This novel process provides a possibility for recycling waste Ni–Cd batteries in a large industrial scale. Keywords: environmental pollution; ferric sulphate; heavy metals; nickel–cadmium batteries; chemical leaching
1. Introduction The Ni–Cd metals have been used in applications that require high energy density, long lifetime and high discharge ratios.[1] These batteries are still used extensively. Therefore, nowadays end-of-life batteries especially the spent Ni–Cd batteries bring more and more environmental problems mainly due to the high content of the heavy metals.[2] Cadmium is considered one of the most toxic metals with a wide variety of adverse effects. It has an extremely long biological half-life that essentially makes it a cumulative toxin. In 1993, cadmium has been designated as a human carcinogen.[3] Thus, the dumping or incineration of spent Ni–Cd batteries may cause serious environmental problems.[4] On the other hand, due to the high content of these metals, they are a suitable source for cadmium and nickel recovery. The pyrometallurgical processes are in use from long time to recover metals from these waste batteries. These methods have some limitations.[4,5] Pyrometallurgical processes are not flexible. They are not easy to control. Also, these methods require high energy. These techniques, similar to those in the mining industry, have proven to be quite expensive or inefficient.[6,7] Moreover, these methods are proven to bring secondary pollution.[8,9] That is why; it is desirable to find an economic and environmentally friendly process to recycle these batteries allowing the recovery of the valuable elements contained. In the bacterial leaching of metals from ores, an iron oxidizing bacteria oxidize metal sulphides.[10] This process is called
∗ Corresponding
author. Email: [email protected]
© 2013 Taylor & Francis
as bioleaching.[2] An effective leaching of heavy metals is due to oxidation of metal compounds by iron oxidizing bacteria and ferric iron produced by iron oxidizing bacteria. Therefore, ferric iron is supposed to be useful for oxidation of metals.[11] The bioleaching is a promising method, but the cycle for bioleaching is too long and currently the known bacteria which are suitable for the treatment for waste Ni– Cd batteries are scarce and hard to culture.[12] Also, all the previous studies with respect to the bioleaching of spent batteries were based on lower pulp density due to very high content of metals and alkaline matter in the spent batteries which were toxic to the bioleaching bacteria.[10,13,14] Cerruti et al. [10] showed that cadmium was more toxic than nickel, producing lag phases at pulp densities higher than 1.0 g/L. They also found that no cell growth was detected within 11 days when pulp densities were higher than 3 g/L. The results of these studies suggest that for a commercially interesting process direct growth of organisms in the presence of metal containing waste is poorly suited and not advisable. Considering these facts, the present study is carried out to develop a new chemical method to reclaim heavy metals from spent Ni–Cd batteries using ferric sulphate hydrate. The direct application of ferric sulphate hydrate for metal leaching will avoid lag phase as seen in the bioleaching process and fasten metal leaching. There will be no efficiency decline due to the presence of toxic metals. Also, this study will further strengthen the role of Fe3+ (as a strong oxidizing agent) in metal solubilization from battery waste.
1264
U.U. Jadhav and H. Hocheng
2. Materials and methods 2.1. Materials The spent Ni–Cd batteries were purchased from the local market. The weight of spent Ni–Cd battery was 20.46 g. Initially, the battery was striped manually. Then plastic, paper and electrodes were separated. A schematic diagram of a dismantled spent Ni–Cd battery is shown in Figure 1.
Downloaded by [University of Toronto Libraries] at 08:26 22 December 2014
2.2.
Preparation of ferric sulphate solution and extraction of metals
A solution containing 20 g/L of ferric sulphate was prepared. Authors examined an efficiency of leaching process at a pH value of 2.5 ± 0.2. The pH of the ferric sulphate solution prepared was kept at 2.5 with sulphuric acid or sodium hydroxide throughout the experiment. Active materials were separated manually from spent-cylindrical Ni–Cd batteries and cut up to obtain different portions. An anodic material (0.10 g) and cathodic material (0.10 g) coming from a spent broken cell was added to the different flasks. In addition, a distilled water control was prepared to assess effects of the low pH condition, an oxidizing environment created by aeration and agitation on solubilization of the metals (data not shown). A leaching experiment was carried out at 30◦ C temperature, 2.5 pH and 150 rpm. Samples were drawn daily in triplicate and centrifuged at 1000 g for 10 min to remove particles. Then, samples were filtered immediately through 0.22 μm membrane filters (PALL Corp., USA) for metal analysis. 2.3. Effect of various physico-chemical parameters An efficiency of leaching process at varying pH values (1– 3) was studied. Active materials from spent battery were added in 100 mL ferric sulphate solution of respective pH
Figure 1. A dismantled spent Ni–Cd battery: (a) paper, (b) nickel active material and (c) cadmium active material.
in 250-mL flasks. The flasks were placed in a shaker incubator at 30◦ C and 150 rpm for the leaching experiment. To study an effect of various concentrations of ferric sulphate on metal leaching, the solutions of varying concentrations of ferric sulphate (20–80 g/L) were prepared in separate flasks. The pH was adjusted to an optimum and effect on leaching of metal was studied. The effect of shaking speed on metal leaching was studied by varying shaking speeds in between 0 and 200 rpm. For this experiment optimum pH and ferric sulphate concentration was selected. To study an effect of temperature on metal leaching, optimum pH, ferric sulphate concentration and shaking speed were selected and the temperature was varied in between 30◦ C and 50◦ C. For each experiment, after exposure to the leaching solution samples were collected and sent to metal analysis. The concentration of metals in the leach liquors was analysed by inductively coupled plasma optical emission spectrometry.
3.
Results and discussion
3.1.
Chemical leaching of Ni–Cd metals from spent batteries The Ni and Cd active materials are shown in Figure 1. The weight of Ni and Cd active materials was 4.87 and 5.51 g, respectively. The Ni–Cd content of electrode materials was determined by dissolving electrode material in aqua-regia separately. Inductively coupled plasma atomic emission spectrometry was used for metal analysis. Active material contained 17.9 (±0.002) and 23.1(±0.018)% Ni and Cd, respectively. Batch leaching experiments were conducted to evaluate the feasibility of the chemical leaching process (by using ferric sulphate) for the removal of Ni and Cd from spent batteries. An effect of leaching time on metal dissolution was studied. Figure 2 illustrates the pattern for metal concentration during the leaching of active materials. Around 61 (±4.1)% Ni and 54 (±3.5)% Cd were
Figure 2. Extraction of metals from spent Ni–Cd batteries using ferric sulphate (20 g/L).
Environmental Technology
Downloaded by [University of Toronto Libraries] at 08:26 22 December 2014
solubilized by ferric sulphate solution in four days. However, under the same conditions, when the leaching time was extended to eight days, dissolution of 88 (±1.8)% Ni and 84 (±2.1)% Cd was achieved. These results indicate that the reaction time has an important role in the dissolution of metals. Ito et al. [15] reported similar observation. The purpose of this study was to clarify an effect of ferric iron as an oxidation reagent for metal compounds. Several researchers compared one-step and two-step bioleaching processes. They also demonstrated feasibility of the spent microbial culture for bioleaching of metals. For industrial applications, bioleaching by spent culture is believed to be desirable to increase leaching efficiency.[16–19] In case
1265
of Acidithiobacillus ferroxidans this spent microbial culture contains mainly Fe3+ which acts as strong oxidizing agent for metal solubilization.[19] As reported in the present study, the direct application of ferric sulphate provided Fe3+ , which acted as strong oxidation agent and caused the solubilization of Cd (1) and Ni (2). Cd0 + 2Fe3+ 2Fe2+ + Cd2+
(1)
Ni0 + 2Fe3+ 2Fe2+ + Ni2+
(2)
Velgosova et al. [20] and Liang et al. [21] also described similar chemical reactions (Reactions 1 and 2) for oxidation of Cd and Ni by Fe3+ . This mechanism of oxidation of metals by Fe3+ is supported by results of Kim et al.[22] They carried out a chemical leaching experiment with CdS and Fe3+ . They suggested that the leaching observed was due to chemical oxidation of CdS by the Fe3+ . In the present study, the leaching system contained only Fe3+ and solubilization of metals proved role of Fe3+ in the leaching process. Since there is no need to wait for growth of microorganism and thereby for conversion of ferrous sulphate to ferric sulphate by microorganism, an operation time for the process will reduce.
3.2. Figure 3. Effect of pH on extraction of metals from spent Ni–Cd batteries after eight day incubation with 20 g/L ferric sulphate solution.
Figure 4.
Effect of physico-chemical parameters on chemical leaching of Ni and Cd from spent batteries pH of the leaching solution is an essential factor that influences the metal dissolution. The leaching efficiency increased with an increase in pH up to 2.5 and thereafter
Effect of increasing ferric sulphate concentration on extraction of metals from spent Ni–Cd batteries.
Downloaded by [University of Toronto Libraries] at 08:26 22 December 2014
1266
U.U. Jadhav and H. Hocheng
showed a downward trend (Figure 3). The maximum dissolution of Ni (88 ± 3.8%) and Cd (84 ± 2.2%) was achieved at 2.5 pH. These results are in agreement with Zhao et al.[2] They found that the maximum dissolution of Cd and cobalt (Co) was achieved at higher pH values (3.0–4.5), while the leaching of Ni was obtained separately in different acidities (pH 2.5–3.5). Figure 4 shows an effect of the addition of increased ferric sulphate concentration on dissolution of Ni and Cd. Initially, it required eight days for dissolution of Ni (88 ± 2.8%) and Cd (84 ± 1.5%) with 20 g/L ferric sulphate solution. The time required for metal dissolution decreased with increased ferric sulphate concentration. By using 60 g/L ferric sulphate concentration dissolution of Ni (88 ± 2.6) %) and Cd (84 ± 4.16%) was achieved in four days. These results indicate that the metal is released due to chemical oxidation of battery waste by ferric ion. Similar observations were reported by Ito et al.[15] They showed that an addition of ferric iron to the sludge increased the initial elution rate of Cd, copper (Cu) and zinc (Zn). An effect of shaking speed on the metal leaching was investigated in the range from 0 to 200 rpm. The results indicate that the leaching is dependent on shaking speed. The dissolution of metal increased with an increase in shaking speed. The maximum dissolution of Ni (88 ± 2.9%) and Cd (84 ± 2.2%) was achieved at 150 rpm (Figure 5). These results are comparable with Aktas.[23] It was suggested that silver dissolution is affected by diffusion-controlled kinetic factors and shaking speed has pronounced effect on silver dissolution. There are some reports which show that the leach temperature exerts a strong influence on the leaching time. The higher the leaching temperature, the shorter is the leaching time.[4,24] In contrast to this observation, in the present study no such effect of temperature on metal dissolution was observed (Figure 6). This is advantageous because the leaching process is difficult to maintain at high temperature due to the loss of a large amount of water.[4]
Figure 5. Effect of shaking speed on extraction of metals from spent Ni–Cd batteries after four day incubation with 60 g/L ferric sulphate solution, at 2.5 pH, and 30◦ C temperature.
Figure 6. Effect of temperature on extraction of metals from spent Ni–Cd batteries after four day incubation with 60 g/L ferric sulphate solution, at 2.5 pH, and 150 rpm shaking speed.
Environmental regulations are becoming more stringent, particularly regarding the disposal of toxic wastes. Therefore, the cost for ensuring environmental protection is continuously rising. Hence, there is a need to utilize more efficient technologies to recover heavy metals from secondary sources in order to minimize capital outlay, and to respond to increased demand.[25] The results of present study showed that the chemical method (use of ferric sulphate) was valid to leach metals from Ni–Cd batteries. An optimal pH, concentration of ferric sulphate, shaking speed and temperature for metal removal were 2.5, 60 g/L, 150 rpm and 30◦ C, respectively. Around 88 (±0.9)% and 84 (±2.8)% of Ni and Cd were recovered, respectively, under an optimal experimental condition in four days. These results indicate that a use of chemical method is advantageous over bioleaching processes. Table 1 shows a comparison between present method and reported bioleaching processes. Cerruti et al. [10] presented the results of experiments using Thiobacillus ferrooxidans culture with sulphur as energy source to dissolve Ni–Cd batteries and to neutralize its electrolyte. They carried out preliminary experiments of dissolution in shake flasks to evaluate the feasibility of a contact leaching process in which the T. ferrooxidans strain used was previously adapted to high concentrations of Ni and Cd. They found that an indirect bioleaching process was more suitable. They arranged two percolators in series. T . ferrooxidans immobilized on elemental sulphur in the first percolator produced acidic growth medium which was used in the second percolator for an extraction of Ni and Cd from a spent battery.[10] In another study, microbial production of sulphuric acid was used as principle for the recovery of the toxic metals from hazardous spent batteries. In this study, a system consisting of a bioreactor, settling tank and leaching reactor was developed to leach metals from Ni–Cd batteries. They employed indigenous thiobacilli, proliferated by using nutritive elements in sewage sludge and elemental sulphur as substrates to produce sulphuric acid. An overflow from the bioreactor was conducted into the
Environmental Technology Table 1.
1267
Comparison of metal extraction from spent Ni–Cd battery using various microorganisms and ferric sulphate solution. Metal reclaim (%)
Reference
Ni
Cd
88.26 (±0.9) 96.50 66.10
84.23 (±2.8) 100 100
Zhao et al. [2]
100
100
Zhao et al. [26]
100
100
–
84
Jadhav and Hocheng (present study) Cerruti et al. [10] Zhu et al. [11]
Downloaded by [University of Toronto Libraries] at 08:26 22 December 2014
Velgosova et al. [27]
settling tank. The supernatant in the settling tank was conducted into the leaching reactor, which contained anode and cathodic electrodes obtained from Ni–Cd batteries. Their results showed that this system was valid to leach metals from Ni–Cd batteries.[2,11] Zhao et al. [2] also showed that the longer the hydraulic retention time was, the more time required to achieve the complete leaching of Ni, Cd and Co. Zhao et al. [26] showed that the dissolution of spent Ni–Cd batteries can be achieved either directly through the metabolism of bacteria or indirectly through the products of the microorganisms. Sewage sludge, as a substitute of pure microorganisms and culture were adopted because indigenous thiobacilli (mixed culture) is present in it as well as some nutrients such as N, P or K. The strains of thiobacilli mainly, including T. ferrooxidans, Thiobacillus thiooxidans and Thiobacillus thioparus can grow and produce sulphuric acid or ferric ions using elemental sulphur or ferrous ions as an energy source with oxygen as the terminal electron acceptor and make the pH decrease substantially.[26] An impact of leaching conditions on Ni recovery was studied by Velgosova et al.[27] Though all these studies show usefulness of bioleaching processes in metal recovery from battery waste, the time required for metal recovery is very large. It varied from 16 days to 93 days in respective studies (Table 1). Also, all these studies used two-stage reactor system. They rely on production of microbial products in the form of sulphuric acid or ferric ions for metal dissolution which took longer time. In the present study, the metal dissolution using ferric sulphate required four days for metal recovery. This shows effectiveness of direct application of ferric sulphate for recovery of metals from battery waste as compared with two stage bioleaching processes. Hence, this could be an economic and effective alternative for recycling spent and discarded batteries.
4.
Conclusion
This research demonstrated a new method which uses ferric sulphate to reclaim the heavy metals from spent Ni–Cd batteries. The dissolution of heavy metals was caused by
Microorganism used
Time for extraction (days)
– At. ferrooxidans Indigenous acidophilic thiobacilli in sewage sludge Indigenous acidophilic thiobacilli in sewage sludge Indigenous acidophilic thiobacilli in sewage sludge At. ferrooxidans and At. thiooxidans
4 93 50 40 16 28
the ferric iron. The described process for metal recovery was shown to be efficient. The ferric iron played a role to oxidize metallic compounds in the battery waste. An application of this method for metal recovery is very interesting from an environmental point of view. During metal recovery ferric sulphate is converted to ferrous sulphate and it can be further used for growth of Acidithiobacillus ferrooxidans to regenerate ferric sulphate. Hence, it will not create secondary pollution. Funding The current research is supported by National Science Council of Taiwan under contract [100-2221-E-007-015-MY3].
References [1] Freitas M, Penha T, Sirtoli S. Chemical and electrochemical recycling of the negative electrodes from spent Ni-Cd batteries. J Power Sour. 2007;163:1114–1119. [2] Zhao L, Yang D, Zhu N. Bioleaching of spent Ni-Cd batteries by continuous flow system: effect of hydraulic retention time and process load. J Hazard Mater. 2008;160:648–654. [3] Waalkes M. Cadmium carcinogenesis in review. J Inorg Biochem. 2000;79:241–244. [4] Yang, C. Recovery of heavy metals from spent Ni-Cd batteries by a potentiostatic electrodeposition technique. J Power Sour. 2003;115:352–359. [5] Bartolozzi M, Braccini G, Bonvini S, Marconi P. Hydrometallurgical recovery process for nickel-cadmium spent batteries. J Power Sour. 1995;55:247–250. [6] Kinoshita T, Yamaguchi K, Akita S, Nii S, Kawaizumi F, Takahashi K. Hydrometallurgical recovery of zinc from ashes of automobile tire wastes. Chemosphere. 2005;59:1105–1111. [7] Xia Y, Li G. The BATINTREC process for reclaiming used batteries. Waste Manage. 2004;24:359–363. [8] Freitas M, Rosalem S. Electrochemical recovery of cadmium from spent Ni-Cd batteries. J Power Sour. 2005;139:366– 370. [9] Bernardes A, Espinosa D, Tenorio J. Recycling of batteries: a review of current processes and technologies. J Power Sour. 2004;130:291–298. [10] Cerruti C, Curutchet G, Donati E. Bio-dissolution of spent nickel-cadmium batteries using Thiobacillus ferrooxidans. J Biotechnol. 1998;62:209–219.
Downloaded by [University of Toronto Libraries] at 08:26 22 December 2014
1268
U.U. Jadhav and H. Hocheng
[11] Zhu N, Zhang L, Li C, Cai C. Recycling of spent nickel– cadmium batteries based on bioleaching process. Waste Manage. 2003;23:703–708. [12] Huang K, Li J, Xu Z. A Novel process for recovering valuable metals from waste nickel-cadmium batteries. Environ Sci Technol. 2009;43:8974–8978. [13] Mishra D, Kim D, Ralph D, Ahn J, Rhee Y. Bioleaching of metals from spent lithium ion secondary batteries using Acidithiobacillus ferrooxidans. Waste Manage. 2008;28:333–338. [14] Xin B, Jiang W, Aslam H, Zhang K, Liu C, Wang R, Wang Y. Bioleaching of zinc and manganese from spent Zn–Mn batteries and mechanism exploration. Bioresour Technol. 2012;106:147–153. [15] Ito A, Umita T, Aizawam J, Takachi T, Morinaga K. Removal of heavy metals from anaerobically digested sewage sludge by a new chemical method using ferric sulfate. Water Res. 2000;34:751–758. [16] Aung K, Ting Y. Bioleaching of spent fluid catalytic cracking catalyst using Aspergillus niger. J Biotechnol. 2005;116:159–170. [17] Wu H, Ting Y. Metal extraction from municipal solid waste (MSW) incinerator fly ash-chemical leaching and fungal bioleaching. Enz Microbiol Technol. 2006;38:839–847. [18] Mishra D, Kim D, Ralph D, Ahn J, Rhee Y. Bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetics aspect. J Hazard Mater. 2008;152:1082– 1091. [19] Hocheng H, Chang J, Jadhav U. Micromachining of various metals by using Acidithiobacillus ferrooxidans 13820
[20]
[21]
[22]
[23] [24] [25] [26]
[27]
culture supernatant experiments. J Cleaner Prod. 2012;20: 180–185. Velgosova O, Kadukova J, Marcincakova R, Palfy P, Trpcevska J. Influence of H2 SO4 and ferric iron on Cd bioleaching from spent Ni-Cd batteries. Waste Manage. 2013;33:456–461. Liang G, Mo Y, Zhou Q. Novel strategies of bioleaching metals from printed circuit boards (PCBs) in mixed cultivation of two acidophiles. Enz Microbiol Technol. 2010;47: 322–326. Kim S, Bae J, Park H, Cha D. Bioleaching of cadmium and nickel from synthetic sediments by Acidithiobacillus ferrooxidans. Environ Geochem Health. 2005;27: 229–235. Aktas S. Silver recovery from spent silver oxide button cells. Hydrometallurgy. 2010;104:106–111. Li M, Wei C, Qiu S, Zhou X, Li C, Deng Z. Kinetics of vanadium dissolution from black shale in pressure acid leaching. Hydrometallurgy. 2010;104:193–200. Hoque M, Philip O. Biotechnological recovery of heavy metals from secondary sources-an overview. Mater Sci Eng C. 2011;31:57–66. Zhao L, Zhu N, Wang X. Comparison of bio-dissolution of spent Ni-Cd batteries by sewage sludge using ferrous ions and elemental sulfur as substrate. Chemosphere. 2008;70:974–981. Velgosova O, Kadukova J, Mrazikova A, Blaskova A, Petoczova M, Harvathova H, Stofko M. Influence of selected parameters on nickel bioleaching from spent Ni-Cd batteries. Mineral Slov. 2010;42:365–368.
Environmental Technology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tent20
Removal of nickel and cadmium from battery waste by a chemical method using ferric sulphate a
Umesh U. Jadhav & Hong Hocheng
a
a
Department of Power Mechanical Engineering, National Tsing Hua University, No. 101, Sec.2, Kuang Fu Rd., 30013 Hsinchu, Taiwan, ROC Published online: 17 Dec 2013.
Click for updates To cite this article: Umesh U. Jadhav & Hong Hocheng (2014) Removal of nickel and cadmium from battery waste by a chemical method using ferric sulphate, Environmental Technology, 35:10, 1263-1268, DOI: 10.1080/09593330.2013.865791 To link to this article: http://dx.doi.org/10.1080/09593330.2013.865791
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Environmental Technology, 2014 Vol. 35, No. 10, 1263–1268, http://dx.doi.org/10.1080/09593330.2013.865791
Removal of nickel and cadmium from battery waste by a chemical method using ferric sulphate Umesh U. Jadhav and Hong Hocheng∗ Department of Power Mechanical Engineering, National Tsing Hua University, No. 101, Sec.2, Kuang Fu Rd., 30013 Hsinchu, Taiwan, ROC
Downloaded by [University of Toronto Libraries] at 08:26 22 December 2014
(Received 24 June 2013; accepted 9 November 2013 ) The removal of nickel (Ni) and cadmium (Cd) from spent batteries was studied by the chemical method. A novel leaching system using ferric sulphate hydrate was introduced to dissolve heavy metals in batteries. Ni–Cd batteries are classified as hazardous waste because Ni and Cd are suspected carcinogens. More efficient technologies are required to recover metals from spent batteries to minimize capital outlay, environmental impact and to respond to increased demand. The results obtained demonstrate that optimal conditions, including pH, concentration of ferric sulphate, shaking speed and temperature ◦ for the metal removal, were 2.5, 60 g/L, 150 rpm and 30 C, respectively. More than 88 (±0.9) and 84 (±2.8)% of nickel and cadmium were recovered, respectively. These results suggest that ferric ion oxidized Ni and Cd present in battery waste. This novel process provides a possibility for recycling waste Ni–Cd batteries in a large industrial scale. Keywords: environmental pollution; ferric sulphate; heavy metals; nickel–cadmium batteries; chemical leaching
1. Introduction The Ni–Cd metals have been used in applications that require high energy density, long lifetime and high discharge ratios.[1] These batteries are still used extensively. Therefore, nowadays end-of-life batteries especially the spent Ni–Cd batteries bring more and more environmental problems mainly due to the high content of the heavy metals.[2] Cadmium is considered one of the most toxic metals with a wide variety of adverse effects. It has an extremely long biological half-life that essentially makes it a cumulative toxin. In 1993, cadmium has been designated as a human carcinogen.[3] Thus, the dumping or incineration of spent Ni–Cd batteries may cause serious environmental problems.[4] On the other hand, due to the high content of these metals, they are a suitable source for cadmium and nickel recovery. The pyrometallurgical processes are in use from long time to recover metals from these waste batteries. These methods have some limitations.[4,5] Pyrometallurgical processes are not flexible. They are not easy to control. Also, these methods require high energy. These techniques, similar to those in the mining industry, have proven to be quite expensive or inefficient.[6,7] Moreover, these methods are proven to bring secondary pollution.[8,9] That is why; it is desirable to find an economic and environmentally friendly process to recycle these batteries allowing the recovery of the valuable elements contained. In the bacterial leaching of metals from ores, an iron oxidizing bacteria oxidize metal sulphides.[10] This process is called
∗ Corresponding
author. Email: [email protected]
© 2013 Taylor & Francis
as bioleaching.[2] An effective leaching of heavy metals is due to oxidation of metal compounds by iron oxidizing bacteria and ferric iron produced by iron oxidizing bacteria. Therefore, ferric iron is supposed to be useful for oxidation of metals.[11] The bioleaching is a promising method, but the cycle for bioleaching is too long and currently the known bacteria which are suitable for the treatment for waste Ni– Cd batteries are scarce and hard to culture.[12] Also, all the previous studies with respect to the bioleaching of spent batteries were based on lower pulp density due to very high content of metals and alkaline matter in the spent batteries which were toxic to the bioleaching bacteria.[10,13,14] Cerruti et al. [10] showed that cadmium was more toxic than nickel, producing lag phases at pulp densities higher than 1.0 g/L. They also found that no cell growth was detected within 11 days when pulp densities were higher than 3 g/L. The results of these studies suggest that for a commercially interesting process direct growth of organisms in the presence of metal containing waste is poorly suited and not advisable. Considering these facts, the present study is carried out to develop a new chemical method to reclaim heavy metals from spent Ni–Cd batteries using ferric sulphate hydrate. The direct application of ferric sulphate hydrate for metal leaching will avoid lag phase as seen in the bioleaching process and fasten metal leaching. There will be no efficiency decline due to the presence of toxic metals. Also, this study will further strengthen the role of Fe3+ (as a strong oxidizing agent) in metal solubilization from battery waste.
1264
U.U. Jadhav and H. Hocheng
2. Materials and methods 2.1. Materials The spent Ni–Cd batteries were purchased from the local market. The weight of spent Ni–Cd battery was 20.46 g. Initially, the battery was striped manually. Then plastic, paper and electrodes were separated. A schematic diagram of a dismantled spent Ni–Cd battery is shown in Figure 1.
Downloaded by [University of Toronto Libraries] at 08:26 22 December 2014
2.2.
Preparation of ferric sulphate solution and extraction of metals
A solution containing 20 g/L of ferric sulphate was prepared. Authors examined an efficiency of leaching process at a pH value of 2.5 ± 0.2. The pH of the ferric sulphate solution prepared was kept at 2.5 with sulphuric acid or sodium hydroxide throughout the experiment. Active materials were separated manually from spent-cylindrical Ni–Cd batteries and cut up to obtain different portions. An anodic material (0.10 g) and cathodic material (0.10 g) coming from a spent broken cell was added to the different flasks. In addition, a distilled water control was prepared to assess effects of the low pH condition, an oxidizing environment created by aeration and agitation on solubilization of the metals (data not shown). A leaching experiment was carried out at 30◦ C temperature, 2.5 pH and 150 rpm. Samples were drawn daily in triplicate and centrifuged at 1000 g for 10 min to remove particles. Then, samples were filtered immediately through 0.22 μm membrane filters (PALL Corp., USA) for metal analysis. 2.3. Effect of various physico-chemical parameters An efficiency of leaching process at varying pH values (1– 3) was studied. Active materials from spent battery were added in 100 mL ferric sulphate solution of respective pH
Figure 1. A dismantled spent Ni–Cd battery: (a) paper, (b) nickel active material and (c) cadmium active material.
in 250-mL flasks. The flasks were placed in a shaker incubator at 30◦ C and 150 rpm for the leaching experiment. To study an effect of various concentrations of ferric sulphate on metal leaching, the solutions of varying concentrations of ferric sulphate (20–80 g/L) were prepared in separate flasks. The pH was adjusted to an optimum and effect on leaching of metal was studied. The effect of shaking speed on metal leaching was studied by varying shaking speeds in between 0 and 200 rpm. For this experiment optimum pH and ferric sulphate concentration was selected. To study an effect of temperature on metal leaching, optimum pH, ferric sulphate concentration and shaking speed were selected and the temperature was varied in between 30◦ C and 50◦ C. For each experiment, after exposure to the leaching solution samples were collected and sent to metal analysis. The concentration of metals in the leach liquors was analysed by inductively coupled plasma optical emission spectrometry.
3.
Results and discussion
3.1.
Chemical leaching of Ni–Cd metals from spent batteries The Ni and Cd active materials are shown in Figure 1. The weight of Ni and Cd active materials was 4.87 and 5.51 g, respectively. The Ni–Cd content of electrode materials was determined by dissolving electrode material in aqua-regia separately. Inductively coupled plasma atomic emission spectrometry was used for metal analysis. Active material contained 17.9 (±0.002) and 23.1(±0.018)% Ni and Cd, respectively. Batch leaching experiments were conducted to evaluate the feasibility of the chemical leaching process (by using ferric sulphate) for the removal of Ni and Cd from spent batteries. An effect of leaching time on metal dissolution was studied. Figure 2 illustrates the pattern for metal concentration during the leaching of active materials. Around 61 (±4.1)% Ni and 54 (±3.5)% Cd were
Figure 2. Extraction of metals from spent Ni–Cd batteries using ferric sulphate (20 g/L).
Environmental Technology
Downloaded by [University of Toronto Libraries] at 08:26 22 December 2014
solubilized by ferric sulphate solution in four days. However, under the same conditions, when the leaching time was extended to eight days, dissolution of 88 (±1.8)% Ni and 84 (±2.1)% Cd was achieved. These results indicate that the reaction time has an important role in the dissolution of metals. Ito et al. [15] reported similar observation. The purpose of this study was to clarify an effect of ferric iron as an oxidation reagent for metal compounds. Several researchers compared one-step and two-step bioleaching processes. They also demonstrated feasibility of the spent microbial culture for bioleaching of metals. For industrial applications, bioleaching by spent culture is believed to be desirable to increase leaching efficiency.[16–19] In case
1265
of Acidithiobacillus ferroxidans this spent microbial culture contains mainly Fe3+ which acts as strong oxidizing agent for metal solubilization.[19] As reported in the present study, the direct application of ferric sulphate provided Fe3+ , which acted as strong oxidation agent and caused the solubilization of Cd (1) and Ni (2). Cd0 + 2Fe3+ 2Fe2+ + Cd2+
(1)
Ni0 + 2Fe3+ 2Fe2+ + Ni2+
(2)
Velgosova et al. [20] and Liang et al. [21] also described similar chemical reactions (Reactions 1 and 2) for oxidation of Cd and Ni by Fe3+ . This mechanism of oxidation of metals by Fe3+ is supported by results of Kim et al.[22] They carried out a chemical leaching experiment with CdS and Fe3+ . They suggested that the leaching observed was due to chemical oxidation of CdS by the Fe3+ . In the present study, the leaching system contained only Fe3+ and solubilization of metals proved role of Fe3+ in the leaching process. Since there is no need to wait for growth of microorganism and thereby for conversion of ferrous sulphate to ferric sulphate by microorganism, an operation time for the process will reduce.
3.2. Figure 3. Effect of pH on extraction of metals from spent Ni–Cd batteries after eight day incubation with 20 g/L ferric sulphate solution.
Figure 4.
Effect of physico-chemical parameters on chemical leaching of Ni and Cd from spent batteries pH of the leaching solution is an essential factor that influences the metal dissolution. The leaching efficiency increased with an increase in pH up to 2.5 and thereafter
Effect of increasing ferric sulphate concentration on extraction of metals from spent Ni–Cd batteries.
Downloaded by [University of Toronto Libraries] at 08:26 22 December 2014
1266
U.U. Jadhav and H. Hocheng
showed a downward trend (Figure 3). The maximum dissolution of Ni (88 ± 3.8%) and Cd (84 ± 2.2%) was achieved at 2.5 pH. These results are in agreement with Zhao et al.[2] They found that the maximum dissolution of Cd and cobalt (Co) was achieved at higher pH values (3.0–4.5), while the leaching of Ni was obtained separately in different acidities (pH 2.5–3.5). Figure 4 shows an effect of the addition of increased ferric sulphate concentration on dissolution of Ni and Cd. Initially, it required eight days for dissolution of Ni (88 ± 2.8%) and Cd (84 ± 1.5%) with 20 g/L ferric sulphate solution. The time required for metal dissolution decreased with increased ferric sulphate concentration. By using 60 g/L ferric sulphate concentration dissolution of Ni (88 ± 2.6) %) and Cd (84 ± 4.16%) was achieved in four days. These results indicate that the metal is released due to chemical oxidation of battery waste by ferric ion. Similar observations were reported by Ito et al.[15] They showed that an addition of ferric iron to the sludge increased the initial elution rate of Cd, copper (Cu) and zinc (Zn). An effect of shaking speed on the metal leaching was investigated in the range from 0 to 200 rpm. The results indicate that the leaching is dependent on shaking speed. The dissolution of metal increased with an increase in shaking speed. The maximum dissolution of Ni (88 ± 2.9%) and Cd (84 ± 2.2%) was achieved at 150 rpm (Figure 5). These results are comparable with Aktas.[23] It was suggested that silver dissolution is affected by diffusion-controlled kinetic factors and shaking speed has pronounced effect on silver dissolution. There are some reports which show that the leach temperature exerts a strong influence on the leaching time. The higher the leaching temperature, the shorter is the leaching time.[4,24] In contrast to this observation, in the present study no such effect of temperature on metal dissolution was observed (Figure 6). This is advantageous because the leaching process is difficult to maintain at high temperature due to the loss of a large amount of water.[4]
Figure 5. Effect of shaking speed on extraction of metals from spent Ni–Cd batteries after four day incubation with 60 g/L ferric sulphate solution, at 2.5 pH, and 30◦ C temperature.
Figure 6. Effect of temperature on extraction of metals from spent Ni–Cd batteries after four day incubation with 60 g/L ferric sulphate solution, at 2.5 pH, and 150 rpm shaking speed.
Environmental regulations are becoming more stringent, particularly regarding the disposal of toxic wastes. Therefore, the cost for ensuring environmental protection is continuously rising. Hence, there is a need to utilize more efficient technologies to recover heavy metals from secondary sources in order to minimize capital outlay, and to respond to increased demand.[25] The results of present study showed that the chemical method (use of ferric sulphate) was valid to leach metals from Ni–Cd batteries. An optimal pH, concentration of ferric sulphate, shaking speed and temperature for metal removal were 2.5, 60 g/L, 150 rpm and 30◦ C, respectively. Around 88 (±0.9)% and 84 (±2.8)% of Ni and Cd were recovered, respectively, under an optimal experimental condition in four days. These results indicate that a use of chemical method is advantageous over bioleaching processes. Table 1 shows a comparison between present method and reported bioleaching processes. Cerruti et al. [10] presented the results of experiments using Thiobacillus ferrooxidans culture with sulphur as energy source to dissolve Ni–Cd batteries and to neutralize its electrolyte. They carried out preliminary experiments of dissolution in shake flasks to evaluate the feasibility of a contact leaching process in which the T. ferrooxidans strain used was previously adapted to high concentrations of Ni and Cd. They found that an indirect bioleaching process was more suitable. They arranged two percolators in series. T . ferrooxidans immobilized on elemental sulphur in the first percolator produced acidic growth medium which was used in the second percolator for an extraction of Ni and Cd from a spent battery.[10] In another study, microbial production of sulphuric acid was used as principle for the recovery of the toxic metals from hazardous spent batteries. In this study, a system consisting of a bioreactor, settling tank and leaching reactor was developed to leach metals from Ni–Cd batteries. They employed indigenous thiobacilli, proliferated by using nutritive elements in sewage sludge and elemental sulphur as substrates to produce sulphuric acid. An overflow from the bioreactor was conducted into the
Environmental Technology Table 1.
1267
Comparison of metal extraction from spent Ni–Cd battery using various microorganisms and ferric sulphate solution. Metal reclaim (%)
Reference
Ni
Cd
88.26 (±0.9) 96.50 66.10
84.23 (±2.8) 100 100
Zhao et al. [2]
100
100
Zhao et al. [26]
100
100
–
84
Jadhav and Hocheng (present study) Cerruti et al. [10] Zhu et al. [11]
Downloaded by [University of Toronto Libraries] at 08:26 22 December 2014
Velgosova et al. [27]
settling tank. The supernatant in the settling tank was conducted into the leaching reactor, which contained anode and cathodic electrodes obtained from Ni–Cd batteries. Their results showed that this system was valid to leach metals from Ni–Cd batteries.[2,11] Zhao et al. [2] also showed that the longer the hydraulic retention time was, the more time required to achieve the complete leaching of Ni, Cd and Co. Zhao et al. [26] showed that the dissolution of spent Ni–Cd batteries can be achieved either directly through the metabolism of bacteria or indirectly through the products of the microorganisms. Sewage sludge, as a substitute of pure microorganisms and culture were adopted because indigenous thiobacilli (mixed culture) is present in it as well as some nutrients such as N, P or K. The strains of thiobacilli mainly, including T. ferrooxidans, Thiobacillus thiooxidans and Thiobacillus thioparus can grow and produce sulphuric acid or ferric ions using elemental sulphur or ferrous ions as an energy source with oxygen as the terminal electron acceptor and make the pH decrease substantially.[26] An impact of leaching conditions on Ni recovery was studied by Velgosova et al.[27] Though all these studies show usefulness of bioleaching processes in metal recovery from battery waste, the time required for metal recovery is very large. It varied from 16 days to 93 days in respective studies (Table 1). Also, all these studies used two-stage reactor system. They rely on production of microbial products in the form of sulphuric acid or ferric ions for metal dissolution which took longer time. In the present study, the metal dissolution using ferric sulphate required four days for metal recovery. This shows effectiveness of direct application of ferric sulphate for recovery of metals from battery waste as compared with two stage bioleaching processes. Hence, this could be an economic and effective alternative for recycling spent and discarded batteries.
4.
Conclusion
This research demonstrated a new method which uses ferric sulphate to reclaim the heavy metals from spent Ni–Cd batteries. The dissolution of heavy metals was caused by
Microorganism used
Time for extraction (days)
– At. ferrooxidans Indigenous acidophilic thiobacilli in sewage sludge Indigenous acidophilic thiobacilli in sewage sludge Indigenous acidophilic thiobacilli in sewage sludge At. ferrooxidans and At. thiooxidans
4 93 50 40 16 28
the ferric iron. The described process for metal recovery was shown to be efficient. The ferric iron played a role to oxidize metallic compounds in the battery waste. An application of this method for metal recovery is very interesting from an environmental point of view. During metal recovery ferric sulphate is converted to ferrous sulphate and it can be further used for growth of Acidithiobacillus ferrooxidans to regenerate ferric sulphate. Hence, it will not create secondary pollution. Funding The current research is supported by National Science Council of Taiwan under contract [100-2221-E-007-015-MY3].
References [1] Freitas M, Penha T, Sirtoli S. Chemical and electrochemical recycling of the negative electrodes from spent Ni-Cd batteries. J Power Sour. 2007;163:1114–1119. [2] Zhao L, Yang D, Zhu N. Bioleaching of spent Ni-Cd batteries by continuous flow system: effect of hydraulic retention time and process load. J Hazard Mater. 2008;160:648–654. [3] Waalkes M. Cadmium carcinogenesis in review. J Inorg Biochem. 2000;79:241–244. [4] Yang, C. Recovery of heavy metals from spent Ni-Cd batteries by a potentiostatic electrodeposition technique. J Power Sour. 2003;115:352–359. [5] Bartolozzi M, Braccini G, Bonvini S, Marconi P. Hydrometallurgical recovery process for nickel-cadmium spent batteries. J Power Sour. 1995;55:247–250. [6] Kinoshita T, Yamaguchi K, Akita S, Nii S, Kawaizumi F, Takahashi K. Hydrometallurgical recovery of zinc from ashes of automobile tire wastes. Chemosphere. 2005;59:1105–1111. [7] Xia Y, Li G. The BATINTREC process for reclaiming used batteries. Waste Manage. 2004;24:359–363. [8] Freitas M, Rosalem S. Electrochemical recovery of cadmium from spent Ni-Cd batteries. J Power Sour. 2005;139:366– 370. [9] Bernardes A, Espinosa D, Tenorio J. Recycling of batteries: a review of current processes and technologies. J Power Sour. 2004;130:291–298. [10] Cerruti C, Curutchet G, Donati E. Bio-dissolution of spent nickel-cadmium batteries using Thiobacillus ferrooxidans. J Biotechnol. 1998;62:209–219.
Downloaded by [University of Toronto Libraries] at 08:26 22 December 2014
1268
U.U. Jadhav and H. Hocheng
[11] Zhu N, Zhang L, Li C, Cai C. Recycling of spent nickel– cadmium batteries based on bioleaching process. Waste Manage. 2003;23:703–708. [12] Huang K, Li J, Xu Z. A Novel process for recovering valuable metals from waste nickel-cadmium batteries. Environ Sci Technol. 2009;43:8974–8978. [13] Mishra D, Kim D, Ralph D, Ahn J, Rhee Y. Bioleaching of metals from spent lithium ion secondary batteries using Acidithiobacillus ferrooxidans. Waste Manage. 2008;28:333–338. [14] Xin B, Jiang W, Aslam H, Zhang K, Liu C, Wang R, Wang Y. Bioleaching of zinc and manganese from spent Zn–Mn batteries and mechanism exploration. Bioresour Technol. 2012;106:147–153. [15] Ito A, Umita T, Aizawam J, Takachi T, Morinaga K. Removal of heavy metals from anaerobically digested sewage sludge by a new chemical method using ferric sulfate. Water Res. 2000;34:751–758. [16] Aung K, Ting Y. Bioleaching of spent fluid catalytic cracking catalyst using Aspergillus niger. J Biotechnol. 2005;116:159–170. [17] Wu H, Ting Y. Metal extraction from municipal solid waste (MSW) incinerator fly ash-chemical leaching and fungal bioleaching. Enz Microbiol Technol. 2006;38:839–847. [18] Mishra D, Kim D, Ralph D, Ahn J, Rhee Y. Bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetics aspect. J Hazard Mater. 2008;152:1082– 1091. [19] Hocheng H, Chang J, Jadhav U. Micromachining of various metals by using Acidithiobacillus ferrooxidans 13820
[20]
[21]
[22]
[23] [24] [25] [26]
[27]
culture supernatant experiments. J Cleaner Prod. 2012;20: 180–185. Velgosova O, Kadukova J, Marcincakova R, Palfy P, Trpcevska J. Influence of H2 SO4 and ferric iron on Cd bioleaching from spent Ni-Cd batteries. Waste Manage. 2013;33:456–461. Liang G, Mo Y, Zhou Q. Novel strategies of bioleaching metals from printed circuit boards (PCBs) in mixed cultivation of two acidophiles. Enz Microbiol Technol. 2010;47: 322–326. Kim S, Bae J, Park H, Cha D. Bioleaching of cadmium and nickel from synthetic sediments by Acidithiobacillus ferrooxidans. Environ Geochem Health. 2005;27: 229–235. Aktas S. Silver recovery from spent silver oxide button cells. Hydrometallurgy. 2010;104:106–111. Li M, Wei C, Qiu S, Zhou X, Li C, Deng Z. Kinetics of vanadium dissolution from black shale in pressure acid leaching. Hydrometallurgy. 2010;104:193–200. Hoque M, Philip O. Biotechnological recovery of heavy metals from secondary sources-an overview. Mater Sci Eng C. 2011;31:57–66. Zhao L, Zhu N, Wang X. Comparison of bio-dissolution of spent Ni-Cd batteries by sewage sludge using ferrous ions and elemental sulfur as substrate. Chemosphere. 2008;70:974–981. Velgosova O, Kadukova J, Mrazikova A, Blaskova A, Petoczova M, Harvathova H, Stofko M. Influence of selected parameters on nickel bioleaching from spent Ni-Cd batteries. Mineral Slov. 2010;42:365–368.
