论文总字数：25185字

摘 要

锂作为21世纪重要的能源材料，被广泛应用于各种行业，包括冶金、润滑脂和润滑剂、铝的生产、医药和锂离子电池工业。近年来，市场对锂的需求逐年增加。盐湖以及海水中都储藏着丰富的锂资源，目前工业提锂还是以盐湖卤水为主要原料。盐湖卤水中锂的含量较高，资源丰富以及提取成本低廉，在所有的锂离子提取方法中，吸附法以其最环保、工艺简单和成本低廉的优点脱颖而出，是从盐湖卤水中回收锂的最有效的方法之一。尖晶石型锂离子筛是从盐湖卤水中提取锂的极具应用前景的锂离子筛分吸附剂，具有选择性高、毒性低、成本低和化学稳定性高等优点，有望用于高镁锂比的盐湖卤水中提取锂。

尖晶石型锂离子筛具有绿色经济、对锂离子吸附容量大且选择性优异的优点，在实际盐湖提锂应用中极具发展研究前景。本文对LiMn₂O₄进行Ga³ 掺杂改性，对Li₄Mn₅O₁₂进行负载成型处理，并分别探究吸附性能。旨在改善粉体离子筛溶损大、流动性差、回收困难等问题。

采用共沉淀-水热法制备出掺杂前驱体LiGa_0.1Mn_1.9O₄，以Ga(NO₃)₃∙xH₂O为镓源，MnCl₂∙4H₂O为锰源。LiOH∙H₂O为锂源，通过控制单变量法，优化了制备方案，考察了Ga³ 掺杂量、水热温度对产物的影响，通过XRD对掺杂前驱体进行结构表征，确定最优合成条件为：Ga³ 掺杂量x= 0.1，水热温度为130 ℃，H₂O₂投加量为2 mL，此时产物的XRD图谱具有标准的尖晶石特征峰。

将掺杂前驱体LiGa_0.1Mn_1.9O₄(LGMO)经酸浸脱锂得到掺杂离子筛HGa_0.1Mn_1.9O₄(HGMO)，考察了离子筛的吸附、脱附及其相关性能。最佳酸洗和脱附的盐酸溶液浓度为0.07 mol/L。吸附约在24 h达到平衡，HMO和HGMO饱和吸附容量分别为22.375 mg/g和22.13 mg/g。最佳脱附时间为1 h，HGMO和HMO的脱锂率都在94%以上，而锰的溶损HGMO(4.39%)小于HMO(6.236%)，证明掺杂Ga³ 降低了离子筛的溶损。进行4次循环吸附实验后，HGMO的循环吸附性能更优。

关键词：锂离子筛 掺杂 吸附 循环利用

Abstract

Lithium as an important energy material in the 21st century, is widely used in various industries, including metallurgy, grease and lubricants, aluminum production, medicine and lithium ion battery industry. In recent years, the market's demand for lithium has increased year by year. Salt lakes and seawater are rich in lithium resources. Currently, industrial salt extraction is still based on salt lake brine. The salt lake brine has a high lithium content, abundant resources and low extraction cost. Among all lithium ion extraction methods, the adsorption method stands out for its advantages of the most environmentally friendly, simple process and low cost. It is the most recoverable lithium from salt lake brine. One of the effective methods. The spinel-type lithium ion sieve is a promising lithium ion sieve adsorbent for extracting lithium from salt lake brine. It has the advantages of high selectivity, low toxicity, low cost and high chemical stability. It is expected to be used for high magnesium lithium Lithium is extracted from brine brine.

The spinel-type lithium ion sieve has the advantages of green economy, large adsorption capacity for lithium ions and excellent selectivity, and has great development research prospects in the practical application of lithium extraction in salt lakes. In this paper, LiMn2O4 was modified by Ga3 doping, and Li4Mn5O12 was subjected to load molding treatment, and the adsorption properties were explored separately. It aims to improve the problems of powder ion sieve, such as large dissolution loss, poor fluidity, and difficult recovery.

Co-precipitation-hydrothermal method was used to prepare the doped precursor LiGa_0.1Mn_1.9O₄, with Ga(NO₃)₃∙xH₂Oas the gallium source and MnCl₂∙4H₂O as the manganese source. LiOH∙H₂O is a lithium source. By controlling the univariate method, the preparation scheme was optimized. The influence of Ga³ doping amount and hydrothermal temperature on the product was investigated. The structure of the doped precursor was characterized by XRD, and the optimal synthesis conditions were determined as : Ga³ doping amount is 0.1, hydrothermal temperature is 130 ℃, H₂O₂ dosage is 2 mL, at this time the XRD pattern of the product has standard spinel characteristic peaks.

The doped precursor LiGa_0.1Mn_1.9O₄(LGMO) was subjected to acid leaching to remove lithium to obtain the doped ion sieve HGa_0.1Mn_1.9O₄(HGMO). The adsorption, desorption and related properties of the ion sieve were investigated. The optimal hydrochloric acid solution for pickling and desorption is 0.07 mol / L. The adsorption reached equilibrium in about 24 h, and the saturated adsorption capacities of HMO and HGMO were 22.375 mg / g and 22.13 mg / g, respectively. The optimal desorption time is 1 h. The delithiation rates of HGMO and HMO are above 94%, and the manganese dissolution loss HGMO (4.39%) is less than HMO (6.236%), which proves that doping Ga3 reduces the dissolution loss of the ion screen . After 4 cycles of adsorption experiments, HGMO has better adsorption performance.

KEYWORDS : Lithium ion sieve ; Dope ; Adsorption ; Recycling use

目录

摘 要 i

Abstract i

目录 1

第1章 文献综述 3

1.1课题背景 3

1.2盐湖提锂研究进展 3

1.3锂离子筛的概念 4

1.4国内外有关提锂的方法 4

1.5锂离子筛分类 5

1.5.1锂锰离子筛前驱体 5

1.5.2锂钛离子筛前驱体 6

1.6锰系离子筛前驱体的制备方法 6

1.6.1高温固相法 7

1.6.2熔融浸渍法 7

1.6.3微波烧结法 7

1.6.4水热合成法 8

1.6.5溶胶-凝胶法 8

1.6.6共沉淀法 9

1.6.7超声喷雾法 9

1.7锰系离子筛掺杂改性 9

1.7.1阳离子掺杂 10

1.7.2阴离子掺杂 10

1.7.3复合离子掺杂 10

1.8课题的主要内容 10

第2章 掺杂改性LiMn₂O₄离子筛的性能研究 12

2.1引言 12

2.2 Ga3 掺杂改性LiMn2O4的制备与表征 12

2.2.1实验试剂及设备 12

2.2.2仪器分析与表征 13

2.2.3实验设计 13

2.3 结果与表征 14

2.3.1 Ga³ 掺杂量对离子筛前驱体结构的影响 14

2.3.2 水热温度对离子筛前驱体结构的影响 16

2.3.3 Ga³ 掺杂改性LiMn₂O₄离子筛表征 17

2.4 Ga³ 掺杂改性LiMn₂O₄的吸附-脱附性能研究 18

2.4.1 实验试剂及设备 18

2.4.2 Ga³ 掺杂前驱体的酸洗 19

2.4.3 吸附动力学研究及模型拟合 19

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