Recovery of lithium from mineral resources: State-of-the-art and perspectives - A review

Lithium (Li), as a new energy metal, is becoming a "hot" topic in both academia and industry due to the rapid vehicle electrification and grid storage. Although brines have been the major Li sources, Li-bearing minerals, owing to the wider distribution and more rapid pathway to market, have also attracted much attention in recent years, with a number of new industrial projects launched and various novel methods proposed. The present study provides a start-of-the-art review of Li recovery from different mineral resources (i.e. excluding brines), and gives perspectives and outlook towards various recovery methods. In this study, the major mineral deposits of Li are summarised and illustrated, which shows its high abundance and wide distribution around the global. Various methods of Li recovery reported so far are then summarised with flowsheets and discussed by different type of minerals, covering spodumene, lepidolite, zinnwaldite, amblygonite and clays. It is predicted that spodumene will continue being dominantly used as Li source over other minerals with sulfuric acid (H2SO4) roasting as a major method of processing. However, other novel methods including direct processing of natural spodumene and the process that favours the direct production of LiOH will be the trends of future research. Fluoride-based methods can achieve low energy consumption and high extraction efficiency but still need to be further investigated for a sustainable, economical and safe application. To compete with spodumene, the comprehensive utilization of all the valuable elements contained in lepidolite and zinnwaldite is crucial. In most of the recovery processes, more attention should be paid to the treatment of voluminous residue and waste for a safe disposal or further reuse. In addition, this study not only presents the methods for Li recovery, but also includes various downstream separation and purification steps to make the process integrated. It is expected that, as a review specialising in mineral resources of Li, the present study can provide insights for the development of this particular area.