基于氨—铵盐体系选择性浸出的动力电池正极废料回收的基础研究

发布时间：2018-01-16 02:14

本文关键词：基于氨—铵盐体系选择性浸出的动力电池正极废料回收的基础研究　出处：《中国科学院大学(中国科学院过程工程研究所)》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,随着锂离子电池在消费电子产品和电动汽车领域应用的快速增长,导致了资源需求的增加。因此,回收废旧锂离子电池不仅能够消除有害组分对环境的污染还能避免资源的短缺。本论文主要针对废锂离子电池正极废料中有价金属Li、Co和Ni的回收,系统开展了氨-铵盐体系选择性浸出正极废料中有价金属Li、Co和Ni的研究,重点包括氨-硫酸铵体系选择性浸出LiNi1/3Co1/3Mn1/3O2正极材料的机理、浸出过程工艺的优化、浸出过程动力学以及氨-铵盐体系选择性浸出废锂离子电池实际物料过程工艺的优化等研究。主要研究内容如下:(1)采用SEM、EDS、以及XPS等表征技术,系统表征了锂离子电池生产废料、废锂离子电池拆解得到的正极材料以及废锂离子电池破碎得到的实际物料。分析发现,相比于生产废料,由于充放电过程中Li离子的嵌入/脱出,导致循环后的废锂离子电池正极材料处于欠锂状态,材料颗粒结构破坏。XPS的分析还发现,锂离子的脱出还导致LiNi0.5Co0.2Mn0.3O2中Ni离子发生氧化,价态升高。(2)通过SEM、EDS、XRD以及XPS分析氨-硫酸铵体系浸出LiNi1/3Co1/3Mn1/3O2正极材料过程机理,发现浸出过程中由于还原反应导致M-O-M键的断裂,层状结构得到破坏。3a位置的Li以Li+形式进入溶液中,3b位置的过渡金属M(Ni、Co、Mn)以Ni(NH3)2+、Co(NH3)m2+以及Mn(NH3)i2+配合物形式存在于溶液中,最终不稳定的Mn(NH3)i2++结合溶液中的阴离子SO32-生成(NH4)Mn(SO3)2 ·H2O沉淀。(3)系统开展了氨-硫酸铵体系选择性浸出LiNi1/3Co1/3Mn1/3O2正极材料的工艺优化,得到最佳工艺。氨水浓度4 mol·L-1,硫酸铵浓度1.5 mol L-1,亚硫酸钠浓度0.5 mol·L-1,搅拌速率500 rpm,固液比10 g·L-1,反应温度353 K,浸出时间300 min下,Li、Ni、Co和Mn的浸出率分别为95.3%、89.8%、80.7%和4.3%配合工艺研究,对浸出过程进行了动力学研究,结果表明浸出过程遵循"未反应收缩核模型",实验条件下Li、Ni和Co的浸出反应的表观活化能分别为83.30 kJ·mol-1、77.93 kJ mol-1和87.92kJ·mol-1,推断浸出反应为界面化学反应控制。(4)针对实际物料,系统开展了氨-碳酸铵-亚硫酸铵体系高效浸出Li、Ni和Co元素的工艺优化,得到最佳工艺。在最佳条件为氨水浓度1 mol·L-1,碳酸铵浓度1 mol·L-1,亚硫酸铵浓度0.5 mol·L-1,固液比100 g·L-1,反应温度353 K,浸出时间180 min下,Li、Ni和Co的浸出率分别为75.1%、81.6%和81.9%,Cu的浸出率达到99%,而Al、Fe和Mn的浸出率均低于1%,有价金属的浸出选择性为94.64%。
[Abstract]:In recent years, with the rapid growth of lithium-ion batteries in consumer electronics and electric vehicles, the demand for resources has increased. The recovery of waste lithium ion battery can not only eliminate the pollution of harmful components to the environment but also avoid the shortage of resources. This paper mainly focuses on the recovery of valuable metals Li-Co and Ni from the waste lithium ion battery cathode waste. The selective leaching of valuable metals Li-Co and Ni from positive electrode waste by ammonia-ammonium salt system was carried out systematically. The mechanism of selective leaching of LiNi1/3Co1/3Mn1/3O2 cathode materials and the optimization of leaching process were emphasized. The kinetics of leaching process and the optimization of practical material process for selective leaching of waste lithium-ion batteries in ammonia-ammonium salt system were studied. The main research contents are as follows: 1) SEMEDS is used. XPS and other characterization techniques, the system characterized the lithium ion battery production waste, waste lithium ion battery decomposition of the cathode materials and waste lithium ion battery broken actual materials. Compared with the waste materials, due to the intercalation / release of Li ions during charge and discharge, the cathode materials of waste lithium ion batteries are in the state of underlithium after cycling, and the analysis of particle structure damage. XPS also found. The removal of lithium ions also leads to the oxidation of Ni ions in LiNi0.5Co0.2Mn0.3O2, the valence of which is increased. XRD and XPS were used to analyze the mechanism of leaching of LiNi1/3Co1/3Mn1/3O2 cathode materials in ammonia-ammonium sulfate system. It is found that during the leaching process the M-O-M bond is broken due to the reduction reaction, and the layer structure of Li at the position of. 3a is broken into the solution in the form of Li in the form of Li, and the transition metal (Mni) Co at the position of 3b is obtained. Mn) exists in the solution in the form of Ni(NH3)2 and Mn(NH3)i2 complex. Anion SO32- formation of NH _ 4H _ 4mn _ 2SO _ 3H _ 2O precipitated in the final unstable Mn(NH3)i2 binding solution. The process optimization of selective leaching of LiNi1/3Co1/3Mn1/3O2 cathode materials by ammonia ammonium sulfate system was carried out systematically. The optimum conditions were as follows: ammonia water concentration 4 mol 路L -1, ammonium sulfate concentration 1.5 mol L -1, sodium sulfite concentration 0.5 mol 路L -1, stirring rate 500 rpm. Under the conditions of solid-liquid ratio of 10 g 路L -1, reaction temperature of 353 K and leaching time of 300 min, the leaching rates of Li Li Ni Co and mn were 95.3% and 89.8%, respectively. The kinetics of the leaching process was studied with 80.7% and 4.3%. The results showed that the leaching process followed the "unreacted shrinking nucleus model" and Li was used in the experiment. The apparent activation energies of leaching reaction of Ni and Co are 83.30 kJ 路mol -1 mol-1 and 87.92 kJ 路mol-1, respectively. It is inferred that the leaching reaction is the control of interfacial chemical reaction. (4) aiming at the actual materials, the process optimization of high-efficiency leaching of Li-Ni and Co in the system of ammonia-ammonium carbonate and ammonium sulfite has been carried out systematically. The optimum conditions were as follows: ammonia concentration 1 mol 路L -1, ammonium carbonate concentration 1 mol 路L -1, ammonium sulfite concentration 0.5 mol 路L -1. The ratio of solid to liquid is 100g 路L ~ (-1), the reaction temperature is 353K, and the leaching time is 180 min. The leaching rates of Ni and Co are 75.1g 路L ~ (-1), 81.6% and 81.9% respectively. The leaching rate of Cu is 99%, while the leaching rate of Alnife and mn is lower than 1. The leaching selectivity of valuable metal is 94.64 4.
【学位授予单位】：中国科学院大学(中国科学院过程工程研究所)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X705;TF803.21

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