Rubidium extraction from mineral and brine resources: A review

Rubidium is a rare alkali metal with high economic value and application potential. It is mainly recovered from the intermediate products of lithium/cesium extraction from lepidolite/pollucite. The application potential and extraction difficulties of rubidium have necessitated the development of new methods for the extraction of rubidium from resources. However, to the best of our knowledge, the extraction of rubidium has received less attention than that of the main group elements, lithium and potassium, and there is no review of the rubidium extraction process to date. Hence, this state-of the-art review addresses the development of rubidium extraction technology and points out the current barriers and potential strategies to achieve the effective rubidium extraction. The review includes the occurrence of rubidium in various resources, and the processes and mechanism of rubidium extraction from mineral (lepidolite, zinnwaldite, pollucite, kaolin, muscovite and biotite) and brine (salt lake and seawater) resources. It is expected that the review can provide insights for the efficient utilization of the rubidium resources.