Available online at www.sciencedirect.com Procedia Environmental Sciences 16 (2012 ) 495 499 The 7 th International Conference on Waste Management and Technology Study on separation of cobalt and lithium salts from waste mobile-phone batteries Gang Jian a, Jia Guo a,, Xing Wang a, Chao Sun a, Ze Zhou a, Long Yu a, Fanhai Kong b, Jian-rong Qiu a a Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan, China b State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan, China Abstract The metals in waste mobile-phone batteries may cause environmental pollution. In this paper, leaching with H 2 SO 4 +H 2 O 2, P507 extraction, and sedimentation with oxalic acid and carbonic acid were used to deal with waste batteries and obtain cobalt and lithium salts by separation, which shows an easy and feasible method with less waste water disposal. The effects of sulphuric acid concentration, ph value, and lithium ions on the recovery were investigated. When the sulphuric acid concentration was over 0.4 mol/l, the loss of cobalt increased significantly. If ph value of 3.5 was used, it was easy for cobalt and lithium separation with a low cobalt loss. Over several recycles, the recovery of lithium could reach the maximum with the lithium ion concentration of 27.3 g/l. The recovery efficiencies for cobalt and lithium were 90.02% and 86.04%, respectively. 2012 2012 Selection The Authors. and/or Published peer-review by Elsevier under responsibility B.V. of Basel Convention Coordinating Centre for Asia and the Pacific and Selection National and/or Center peer-review of Solid Waste under Management, responsibility Ministry of Basel of Convention Environmental Coordinating Protection Centre of China. for Asia and the Pacific and National Center of Solid Waste Management, Ministry of Environmental Protection of China. Open access under CC BY-NC-ND license. Keywords: waste mobile-phone battery; separation and recovery; cobaltous oxalate; lithium carbonate 1. Introduction With the advantages of light weight, large capacity, long service life, etc, lithium-ion secondary battery has become an extensively used portable power [1]. Benefiting form the popularity of mobile phones, laptops, digital cameras, the production and consumption of the lithium battery straight to soar. In 2008, cell phone production in China was about 300 million, which means if each cell phone matches 1.5 batteries on average, then the amount of Li-ion battery production reached 450 million. After hundreds of times of charging and discharging, batteries expansion and capacity decline till scrapped. So the service Corresponding author. Tel.: +0086-27-87194980; fax: +0086-27-87195671. Email address: guojia@mail.wit.edu.cn. 1878-0296 2012 Selection and/or peer-review under responsibility of Basel Convention Coordinating Centre for Asia and the Pacific and National Center of Solid Waste Management, Ministry of Environmental Protection of China Open access under CC BY-NC-ND license. doi:10.1016/j.proenv.2012.10.068
496 Gang Jian et al. / Procedia Environmental Sciences 16 ( 2012 ) 495 499 life is 2 to 3 years [2]. Accordingly, the huge battery consumption also brings a startling quantity of waste batteries. However, lithium battery recovery rate is very low due to some technical and economic issues. A large number of waste batteries have been abandoned, which not only cause harmfulness to the environment, but also a waste of resources [3]. A small cell phone battery may become a "killer" of the environment and human health after scrapped. For instance, the dose of cadmium in one battery could contaminate the water of three standard pool, while copper, aluminum, electrolyte and other non-ferrous metals also cause great pollution to the environment-contaminate groundwater and soil. Accordingly, people long time exposure to these metal ions may lead to nervous system and respiratory system diseases [3]. Currently, the methods of separation and recovery lithium in batteries are adding precipitant after treatment, which converts lithium-ion into the precipitation. Then we could calcinate it and absorb the lithium-ion steaming out in form of lithia vapor. D. S. Kim [4] studied on separation of LiCoO 2 and manufactured stainless steel pressure boiler with two Teflon chambers. Then put LiCoO 2, conductive carbon, binder and diaphragm in this device and separate LiCoO 2 at 200 o C by hydrothermal method. This method is mainly based on the mechanism of "dissolution - precipitation". Yong-xun JING[5] recovers lithium and cobalt oxide from waste lithium-ion batteries by flotation. The electrode material is heated at 500 o C in muffle furnace after pretreatment (organic binder would volatilize and the surface of lithium cobalt oxide would change from hydrophobic to hydrophilic), then separate lithium cobalt oxide from graphite via flotation. In the optimum flotation conditions (kerosene=0.2 kg/t, MIBC=0.14 kg/t, concentration of slurry solids = 10%), lithium and cobalt content is more than 93% and cobalt recovery rate reaches 90% by this method. The above method has simple step and higher recovery characteristics, but the high facility cost and demanding operation request are not suitable for industrialization[6]. 2. Experimental 2.1. Raw material and reagents The specification of lithium battery is 1020 ma/h. Lithium-ion secondary battery is composed of shell and internal battery cell. Specifically, shell is nickel plated steel and battery cell is spiral structure which mainly consists of cathode, anode, isolating membrane and electrolyte. Batteries' cathode material consists of about 90% activated lithium cobalt oxide, 7 8% conductive acetylene black and 3 4% organic binder. The isolation membrane is the polypropylene membrane while electrolyte is organic carbonate solution of lithium hexafluorophosphate[7]. The chemical reagents contain NaOH, Al(OH) 3, H 2 SO 4, H 2 O 2, TBP, sulphonating kerosene, oxalic acid, saturated sodium carbonate solution, etc. 2.2. Separation principle Under the consideration of environmental protection and security of the leaching process, a brand-new proposal of low liquid-to-solid ratio using H 2 SO 4 +H 2 O 2 system as extraction solution has been chosen. Leaching solution from experiment contains very minor amount of iron and the PH endpoint of leaching is 3.5, which avoid removing iron in traditional high-liquid-solid ratio leaching process. It achieves the purpose of selective leaching of cobalt and lithium [8, 9]. Using Organophosphorus P507 as an extractant, TBP as a modifier and Sulfonated kerosene as a diluent, cobalt extraction from solution will reach a high rate by twice extraction while lithium extraction rate is very low. Then, the coextraction lithium in organic phase can be removed by dilute sulfuric acid, which achieves the separation of cobalt and lithium. After adding sulfuric acid, P507 extraction experiment raffinate can be recycled as leaching solution. This process makes the lithium ions increase
Gang Jian et al. / Procedia Environmental Sciences 16 ( 2012 ) 495 499 497 gradually in the leaching-extraction system. Thus, we should precipitate lithium by using saturated sodium carbonate when lithium ion concentration reaches a certain level in raffinate[10-12]. 2.3. Process flow diagram of valuable metal recovery from waste lithium batteries Waste lithium batteries Split into cathode and anode Scrap cathode to get the aluminum foil and powder Processing anode material with sulfuric acid Recovery of copper Recovery of aluminum Acid leaching in low liquid-to-solid ratio P507 solvent extraction Raffinate Loading organic phase Precipitate lithium with saturated sodium carbonate solution Precipitate cobalt with oxalic acid Li 2 CO 3 CoC 2 O 4 Fig. 1. Process flow diagram of valuable metal recovery from waste lithium batteries 3. Results and Discussion 3.1. Effect of acid type on cobalt leaching rate Leaching experiments were carried out of hydrochloric acid, nitric acid and sulfuric acid, respectively. The results are shown in Table 1. The most efficient acid is hydrochloric acid, followed by nitric acid and sulfuric acid is lowest. However, due to the use of HCl and HNO 3 in leaching process of the mixed powder causing harmful chlorine and nitrogen oxides which will pollute the environment, the cost must be increased by using exhaust gas treatment device. Consequently, using sulfuric acid as the leaching solution is both environmentally friendly and safe.
498 Gang Jian et al. / Procedia Environmental Sciences 16 ( 2012 ) 495 499 3.2. Effect of acid concentration on leaching cobalt loss As it can be seen from Fig. 1, the Co-loss rate rises with the increase of sulfuric acid concentration. In particular, the Co-loss rate shoots up when sulfuric acid concentration exceeded 0.4mol / L. As a result, sulfuric acid concentration close to 0.4mol/L is used in Sulfuric acid-hydrogen peroxide system, which reduced Co-loss effectively. Table 1. Effect of types of acid on cobalt leaching rate Time/h Hydrochloric acid leaching rate /% Time/h Nitric acid leaching rate/% Time/h Sulfuric acid leaching rate/% 0.5 40.0 1.0 60.3 1.0 30.8 1.0 70.1 1.5 80.5 2.0 49.2 1.5 99.2 2.5 90.4 3.0 79.7 90 70 80 60 Recovery of lithium-ion/% 70 60 50 40 30 20 10 0 5 10 15 20 25 30 35 40 45 Lithium-ion concentration/(g/l) ß 50 40 30 20 10 0 0 1 2 3 4 5 6 ph Fig. 2. Effect of acid concentration on cobalt loss Fig. 3 Effect of ph on separation factor of cobalt and lithium 3.3. Effect of ph on separation factor of leaching of cobalt and lithium The effect of ph on the separation factor of leaching of cobalt and lithium is shown in Fig. 2. As the ph increasing, the separation factor of cobalt and lithium is greater and the change becomes flat after reaching ph=4.0. Under the consideration of the impact on Co-loss by different acid concentration, ph=3.5 has been chosen, which not only achieves a greater degree of separation but also reduces the loss of cobalt 3.4. Lithium-ion concentration on the precipitation of lithium Only when lithium-ion concentration exceeding 25g/L can, we achieve a higher rate of precipitation. Therefore, precipitation of lithium has to been carried out after seven leaching-extraction cycles. Then the lithium-ion concentrations in raffinate phase reaches 27.3g/L and the recovery of lithium-ion could reach a higher rate. 4. Conclusions
Gang Jian et al. / Procedia Environmental Sciences 16 ( 2012 ) 495 499 499 Experimental results show that leaching batteries with H 2 SO 4 +H 2 O 2 system will not generate harmful gases, and will not threaten the environment; the end of leaching ph=3.5 avoids iron removal step in traditional high-liquid-solid ratio leaching process. Leaching with H 2 SO 4 +H 2 O 2, P507 extraction, and sedimentation with oxalic acid and carbonic acid were used to deal with waste batteries and obtain cobalt and lithium salts by separation, which showed an easy and feasible method with less waste water disposal. The recovery rates for cobalt and lithium were 90.02% and 86.04%, respectively. Acknowledgements The financial supports from National Natural Science Foundation of China (21076165), Hubei Key Laboratory of Coal Conversion and Novel Carbon Materials Open Fund (WKDM201101), Foundation of State Key Laboratory of Coal Combustion (FSKLCC1008), and the Third WIT Innovation Foundation for Postgraduate Students (CX201104) are gratefully acknowledged. References [1] Nie Yong-feng, Li Jing-hui. Study on the national action plan of Hazardous waste management[a]. International Conference on Solid Waste Pollution Control and Resources Recovery [C]. Central South University Press, 2001. 4-7. [2] Yang Shao-bin, Hu Hao-quan. Lithium-ion Battery and Battery Industry[J]. Journal of Liaoning Technical University, 2000, 19 (6): 659-663. [3] Yu Yu-xin, Li Jian-jun. Recovery and Disposal of Waste Battery in China[J]. Sichuan Environment, 2004, 23(1): 94-96. [4] Danuza Pereira Mantuano, Germano Dorella, Renata Cristina Alves Elias. Analysis of a hydrometallurgical route to recover base metals from spent rechargeable batteries by liquid -liquid extraction with Cyanex 272[J]. Journal of Power Sources, 2006, 159: 1510-1514. [5] Shin Shun Myung, Kim Nak Hyoung, Sohn Jeong Soo, YangDong Hyo, Kim Young Han. Development of a metal recovery process from Li-ion battery wastes[j]. Hydrometallurgy, 2005, 79: 172-175. [6] Wang de-yi, Gao Shu-xia. Waste battery recycling and environment protection[j]. Recycling Research, 2003, 6: 20-24. [7] Zhang Zheng-Jie,Yang Jin-Xia. The Recycling Recovery Method of The Lithium Ion Battery[J]. Non-ferrous Mining and Metallurgy, 2005, 21(6): 46-49. [8] Dorella G, Mansur M B. A study of the separation of cobalt from spent Li-ion battery residues[j]. Journal of Power Sources, 2007, 170: 210-215. [9] Pan Ze-qiang, Yang Sheng-hai. Preparation of Cobalt Product Using Scraps of Co-Li Film[J]. Chinese Journal of Rare Metals, 2002, 26(1): 39-41. [9] Tian Jun, Yin Jing-qun, Ouyang Ke-xian. Study and Application of Extracting Co from Ni with Cyanex 272[J]. Chinese Journal of Rare Metals, 1999, 23(6): 450-453. [10] Guo Li-ping, Huang Zhi-liang, Fang Wei. Recycling of Co and Li in LiCoO2 by chemical precipitation method[j]. Battery Bimonthly, 2005, 35(4): 266-269. [11] Nan Junmin, Han Dongmei, ZuoXiaoxi. Recovery of metal values from spent lithium-ion batteries with chemical deposition and solvent extraction[j]. Journal of Power Sources, 2005, 152: 278-281.