Abstract:

With the rapid development and wide application of power battery vehicles, the demand for lithium resources has increased sharply. How to realize the efficient utilization and development of lithium resources in salt lakes, which has international resource advantages in China, is a key issue that the salt lake chemical industry needs to solve urgently in recent decades. Compared with the salt lakes that have been developed and utilized abroad, except for some salt lakes in Xizang, the lithium resources in China's salt lakes are mostly low-grade resources with lithium concentrations as low as tens of mg/L and extremely high magnesium lithium ratio (about 500 or even higher). Up to now, based on the characteristics of lithium resources in salt lakes, several methods have been developed to extract lithium from salt lakes, such as membrane method, adsorption method, solar pool method, solvent extraction method and electrochemical method, some of which have been successfully applied in the actual industrial production of lithium extraction from salt lake brines. Especially, adsorption method has attracted much attention due to its characteristics of high Li⁺ selectivity, good applicability, simple process, green efficiency and recyclability. Layer-structured aluminum-based adsorbents (Li/Al-LDHs) have been successfully industrialized due to their high selectivity, green environmental protection and other advantages. However, there are still some problems such as extremely low dynamic adsorption capacity and serious pulverization in the large-scale application of this kind of adsorbent, which need further study and discussion. Therefore, based on the structure-activity relationship between the adsorption properties of Li/Al-LDHs and the crystal structure, this paper summarized the reasons for the short cycle period and poor application performance of Li/Al-LDHs adsorbent, and proposed the performance improvement scheme from the perspective of structural stability.

Key words: lithium, salt lake, adsorbents, crystal structure, structure stability

摘要：

随着动力电池车的快速发展和广泛应用，锂资源的需求量急剧增加。如何实现我国具有国际资源优势的盐湖锂资源高效利用开发是近几十年来盐湖化工产业亟需解决的关键问题。与国外已实现开发利用的盐湖相比，除了西藏部分盐湖以外，我国盐湖锂资源大多是锂浓度低至几十mg/L、镁锂比极高（约500，甚至更高）的低品位资源。截至目前，基于我国盐湖锂资源的特征，已开发了几种盐湖提锂方法，如膜法、吸附法、太阳池法、溶剂萃取法和电化学法等，部分已成功应用于实际盐湖卤水提锂产业化生产中。其中，吸附法因高Li⁺选择性、良好的适用性、工艺简单、绿色高效和可循环利用等特性而备受关注。层状结构铝系吸附剂（Li/Al-LDHs）因具有较高的选择性、绿色环保等优势已成功实现产业化应用。然而，该类吸附剂在规模化应用时仍存在动态吸附容量极低、粉化严重等问题，有待进一步深入研究探讨。从Li/Al-LDHs吸附性能与晶体结构间构效关系出发，梳理总结了Li/Al-LDHs吸附剂循环周期短、应用性能差的原因，并从结构稳定性的角度出发，提出了性能提升的解决方案。

关键词: 锂, 盐湖, 吸附剂, 晶体结构, 结构稳定性