A review on extraction technologies of rubidium and cesium from mineral and brine resources

Rubidium (Rb) and cesium (Cs), are rare alkali metals in high-tech fields, covering aviation, photovoltaics, and medicine. Present studies have explored separation technologies oriented towards single resource of Rb or Cs, without summarizing the characteristics of Rb and Cs resources and their separation technologies. This review innovatively adopted the systematical perspective of “resource characteristics − technical principles − application challenges” to sort out the strategies for recovering Rb and Cs from different resources ranging from high-grade ores to low-concentration brines. For mineral resources, three typical ores (lepidolite, pollucite, and zinnwaldite) were selected to compare the advantages and limitations of pyrometallurgy and hydrometallurgy techniques. Brines have gradually become a more sustainable resource of Rb and Cs. This paper explores various highly selective methods for the separation and extraction of Rb and Cs. All methods face common challenges: energy consumption issues, environmental impacts, reagent costs, and selectivity problems in multi-ion systems. The future research would focus on breaking through the limitations of a single technology, dedicated to developing green coupling processes with low energy consumption and low environmental impact, and enhancing scalability and economic feasibility through interdisciplinary approaches to achieve sustainable recycling of Rb and Cs. This review not only provides researchers with clear advantages and disadvantages of technical methods, but also customizes separation schemes based on resource characteristics.