École Nationale Supérieure de
Techniques Avancées

Résumé

Classified as a conflict mineral, Tantalum is getting harder and harder to acquire on the international market. To deal with this issue, the French ANR (Agence Nationale de la Recherche) have funded a research program about the recycling of Tantalum in WEEE (Wastes from Electrical and Electronic Equipment). During this internship, several analyses have been done in solutions of tantalum, under the form of hexatantalate ions. Presence of WEEE leftovers have been controlled in order to better understand the precipitation of hexatantalate ions with Ca and Mg. Speciation of these solutions and the gathered precipitates have been performed using ICP-AES (Inductive Coupled Plasma Atomic Emission Spectrometry) and ATR-FTIR (Attenuated Total Reflectance Fourier-Transform Infrared) Spectrometry methods. It has been discovered that magnesium has a better precipitation yield than calcium, linked with the anomalous solubility of Hexatantalate ions. However, when being in presence of WEEE leftovers, tantalum precipitates with other species in solution, and only a few portions of this metal is extracted by magnesium. This method of extraction doesn’t seem efficient for the moment, but further analyses are scheduled, in order to determine the nature of the precipitate formed with the WEEE solution and tantalum.