Synergistic extraction of lithium, rubidium, and cesium from lepidolite: Steam roasting for defluorination and DFT calculation

作者：Yakai Yang, Peidong Yang, Dongqi Song, Jianyong He, Hui Guo, Min Gan, Xiaohui Fan · 发表于：Green and Smart Mining Engineering · 年份：2025 · DOI：10.1016/j.gsme.2025.09.007 · 被引用次数：8 · 研究领域：Extraction and Separation Processes、Radioactive element chemistry and processing、Chemical Synthesis and Characterization

Lepidolites are important carriers of Li ores. Because of the strong positive correlation between the presence of Li and F, Li extracted from lepidolite must be defluorinated. Moreover, synergistically extracting Li, Rb, and Cs is important for the comprehensive utilization of lepidolite. Steam roasting converts F to HF without introducing impurities. In this study, the effects of steam roasting on Li activation and the synergistic extraction of Rb and Cs were investigated during the defluorination process. Notably, the defluorination mechanism and migration behavior of F during steam roasting were revealed based on qualitative and quantitative analyses of the liquid and corresponding solid phases. Furthermore, density functional theory calculations were used to investigate the pathways and behaviors of defluorination and the removal behavior of F atoms connected to Al and Li sites, revealing that the F atoms on the (010) crystal surface were easily replaced by water molecules, thereby releasing surface F atoms. Under the optimal roasting conditions, the defluorination efficiency of lepidolite was 91.08% at 880°C for 1 h. Subsequently, the Li encapsulated in the crystal lattice, as well as Rb and Cs, was activated and leached using optimal sulfuric acid leaching. The leaching efficiencies of Li, Rb, and Cs were 97.37%, 97.77%, and 97.19%, respectively at 120°C for 2 h. This study provides a comprehensive and systematic perspective on the defluorination and comprehensive utili...