【作者】 何卓；

【导师】 张贵清； 陈礼运；

【作者基本信息】 中南大学 ， 资源与环境（专业学位）， 2023， 硕士

【摘要】 近年来随着国家一系列优惠政策的颁布,新能源行业得到快速发展,而锂离子电池是这些新能源领域发展的核心。目前,不管是从矿石和盐湖卤水中,还是从废旧锂离子电池正极材料中提取锂,大部分工艺会得到含锂硫酸钠溶液,而传统的处理工艺面临着耗能大、成本高、锂损失大、产品钠污染等问题,目前缺少从含锂硫酸钠溶液中有效提取锂和分离锂钠经济有效的方法。因此,如何经济高效从含锂硫酸钠溶液中分离锂钠并回收富集其中的锂具有非常重要的现实意义。针对从含锂硫酸钠碱性溶液中提取锂工艺流程复杂、锂回收率低、锂钠分离困难、产品钠污染严重、能耗与生产成本高等问题,通过分析比较不同协同萃取体系选择性提锂与分离锂钠的效果,提出了两种新型的协同萃取体系LIX54/Cyanex923与LIX54/HBL320从含锂硫酸钠碱性溶液中选择性萃取锂。研究的主要内容及结果如下:（1）为了探究最优的锂钠分离协同萃取体系,考察了不同萃取剂分离锂钠的效果以及加入不同协萃剂后协同萃锂的效果。在选定最优的协同萃取体系后考察了有机相锂负载量、有机相浓度对分相效果的影响和其协同萃取效果。结果表明:LIX54/Cyanex923与LIX54/HBL320两种协同萃取体系能够实现锂钠的高效分离与锂的高倍富集回收,同时分相性能很好。（2）对LIX54/Cyanex923协同萃取体系进行了系统的工艺研究,考察了萃取过程中萃取剂浓度、协萃剂浓度、温度、平衡p H值、时间等因素对萃取的影响,并进行了模拟串级实验。实验结果表明:优化条件下锂的单级萃取率达到99.6%,锂钠分离系数β_Li/Na达到1500以上。对于含锂0.5g/L、钠50 g/L的模拟料液,经过3级逆流萃取,锂的萃取率达到99%以上,2级逆流洗涤后,负载有机相中钠的浓度低于0.05 g/L。2级逆流反萃后,反萃液中锂和钠的含锂分别为16.93 g/L和0.61 g/L。（3）对LIX54/HBL320协同萃取体系进行了系统的工艺研究,考察了萃取过程中萃取剂浓度、协萃剂浓度、温度、平衡p H值、时间等因素对萃取的影响,并进行了模拟串级实验。实验结果表明:优化条件下锂的单级萃取率超过95%,锂钠分离系数β_Li/Na超过200。模拟串级实验结果表明,经过4级逆流萃取后,锂的萃取率几乎达到100%,经过两级逆流洗涤能够洗脱93.5%以上的钠,洗后有机相中钠浓度低于0.05 g/L。洗后负载有机相经过两级逆流反萃,反萃液中锂浓度超过38.79 g/L。（4）进行了LIX54/HBL320协同萃取体系从实际含锂硫酸钠溶液中提取锂的连续运转试验。对于锂钠逆流萃取连续运转试验,优化条件下锂的萃取率达99.5%以上,反萃液锂浓度30 g/L左右,锂钠比大于5,反萃液可用于碳酸钠沉锂制备电池级碳酸锂。对于锂钠分馏萃取连续运转实验,优化条件下锂的萃取率达97%以上,反萃液锂浓度可以达到28 g/L左右,钠浓度低于30 mg/L,锂钠比大于1000,反萃液可用于制备电池级单水氢氧化锂。图56幅,表35个,参考文献99篇更多还原

【Abstract】 In recent years,with the promulgation of a series of preferential policies,the new energy industry has been developing rapidly,and lithium-ion battery is the core of the development of these new energy fields.At present,there will inevitably get sodium sulfate solution containing lithium whether from ore,salt-lake brine and spent lithium-ion battery cathode material extraction lithium.The traditional treatment process is faced with high energy consumption,high cost,lithium loss,product sodium pollution and other problems.There is a lack of economic and effective methods to extraction lithium and separation of lithium and sodium from sodium sulfate containing lithium.Therefore,it is of great practical significance to economically and efficiently separate and recover lithium from sodium sulfate solution containing lithiumIn view of the problems in the process of extracting lithium from alkaline sodium sulfate solution,such as the complex process,a low recovery rate of lithium,difficult separation of lithium and sodium,serious sodium pollution of product,high energy consumption and production cost,the effects of selective extraction and separation of lithium and sodium by different collaborative extraction systems were analyzed and compared.Two new synergistic extraction systems,LIX54/Cyanex923 and LIX54/HBL320,were proposed for selectively extracting lithium and separation of lithium and sodium from alkaline sodium sulfate solution.The main contents and results of the study are as follows:（1）In order to explore the optimal lithium sodium separation synergistic extraction system,the separation effect of lithium and sodium with different extractants and the synergistic extraction effect of lithium with different auxiliaries were investigated.After selecting the optimal collaborative extraction system,the influence of organic phase lithium loading and organic phase concentration on the phase separation and synergistic extraction effects were investigated.The results showed that LIX54/Cyanex923 and LIX54/HBL320synergistic extraction systems could achieve high efficiency separation of lithium and sodium and high enrichment and recovery of lithium,and had good phase separation performance.（2）The process of LIX54/C923 collaborative extraction system was systematically studied,and the influences of extraction concentration,temperature,equilibrium p H,time and other factors on extraction were investigated.Under the optimal conditions,the results show that over 99.6%of lithium was extracted and the separation coefficient of lithium sodiumβ_Li/Nareaches more than 1500.From the feed solution containing of 0.5 g/L Li⁺and 50g/L Na⁺,the results of three-stage counter-current extraction showed that over 99%of lithium was extracted.After two-stage counter current scrubbing,leaving less than 0.05 g/L Na⁺in the loaded organic phase.The scrubbed organic phase was stripped by two-stage counter current stripping,resulting in 16.93 g/L Li and 0.61g/L in the strip liquor.（3）A novel synergistic solvent extraction system consisting of LIX54 and HBL320 in sulfonated kerosene to recover lithium from sodium sulfate solutions has been developed.The effects of extractant concentration and equilibrium p H on the extraction of lithium were investigated.The results showed that over 95%of lithium was extracted from a synthetic solution containing 3 g/L Li⁺and 30 g/L Na⁺in a single contact,resulting in a separation factor of lithium over sodium larger than 200.The results of four-stage counter-current extraction showed that almost 100%of lithium was extracted.After two-stage counter current scrubbing,93.5%sodium was scrubbed,leaving less than 0.05g/L Na⁺in the loaded organic phase.The scrubbed organic phase was stripped by two-stage counter current stripping,resulting in 38.97 g/L Li⁺in the strip liquor.（4）The continuous operation test of lithium extraction by LIX54/HBL320system was carried out.The experimental results show that:For the continuous operation test of lithium sodium countercurrent extraction,the extraction rate of lithium is more than 99.5%,the concentration of lithium in raffinate is about 30mg/L and the Li/Na ratio is more than 5.The stripping liquid can be used for the preparation of battery grade lithium carbonate by precipitation of lithium with sodium carbonate.For the continuous operation test of lithium sodium fractionation extraction,the extraction rate of lithium reaches more than 97%,the concentration of lithium in raffinate can reach about 28 g/L,the concentration of sodium is less than 30 mg/L,and the Li/Na ratio is more than 1000.The stripping liquid can be used to prepare battery grade single-water lithium hydroxide.更多还原