Advancements in the extraction of niobium and tantalum: Innovative strategies in hydrometallurgical processes

This article presents a comprehensive analysis of the challenges and advancements in the extraction of niobium (Nb) and tantalum (Ta), focusing on global production and the growing demand for strategic and critical metals. The extraction of these metals from their primary and secondary resources is carried out through well-known metallurgical techniques, based on the use of hydrofluoric acid in the various production chains. However, the operational processes and their sustainable production are hindered due to the negative impacts produced during the process, resulting in a particular challenge for the extraction of these two metals. Therefore, pyrometallurgical and hydrometallurgical processes have been explored as emerging alternatives to the existing commercial processes. Thermal treatment processes in acidic and alkaline media have been shown to be capable of preparing PLS loaded with the metals of interest. On the other hand, leaching using mineral and organic acids is essential for the efficient recovery of Nb and Ta, highlighting their advantages and limitations. Additionally, the precipitation of acidic or basic liquors from hydrometallurgy is described to advance towards selective recovery stages. In this context, emphasis is placed on traditional and novel extractants according to their separation function, to ensure the high quality of the products through current technology.