Evaluación de la aplicación de disolventes eutécticos profundos basados en cloruro de colina para la lixiviación de metales (cu, pb, fe y zn) provenientes de un concentrado polimetálico.

Abstract

Deep eutectic solvents (DES) are emerging as an environmentally friendly alternative that could replace traditional industrial solvents. However, the use of DES in the leaching of polysulfide minerals is limited. This study aims to evaluate the characteristics of DES as solvents for the beneficiation of an Ecuadorian polymetallic concentrate. First, the chemical and mineralogical characterization of this concentrate was performed. Subsequently, three DES based on choline chloride (ChCl) were prepared: reline (urea-ChCl), ethaline (ethylene glycol-ChCl) and glyceline (glycerin-ChCl). These DES were characterized by thermogravimetry and infrared spectroscopy. Then, dissolution tests were carried out with these DES and different metal bearing compounds (Cu, Fe, Pb and Zn sulfates, oxides, and sulfides). Finally, leaching tests of the concentrate were carried out. It was determined that the metalbearing minerals in the concentrate were: chalcopyrite, pyrite, anglesite, and sphalerite. Thermogravimetric analysis showed that DES are stable at the test temperature (30°C) and even at higher temperatures (150°C). Using the infrared spectrophotometry of the DES, the presence of functional groups of the pure individual components was identified. Regarding the dissolution tests, it was found that the solubility of the metal is dictated by the bearing species, reaching higher values for sulfates, followed by oxides and finally sulfides. In the case of concentrate, a higher recovery of lead (90%) was achieved, followed by zinc (40%), copper (30%) and iron (10%).