Thermal and Acid Oxidative Strategy to Recovery Selenium and Silver from Eucairite CuAgSe

Abstract

Sulphides and selenides are mineral species that commonly occur together in natural deposits, according to the relative abundance. Moreover, the emerging importance of selenium in several fields of sciences, the economic value of the metal silver, commonly associated to selenide by chemical affinity and the existence of selenium deposits in Argentina lead to study the CuA_gSe eucairite oxidation process in air atmosphere, by thermal and acid treatments in order to the Se and Ag recovery. The analysis was carried out with pure mineral by means of (TGA-DTGA) Thermogravimetric technique, X-ray Diffraction (XRD), Infrared Spectroscopy (FTIR), Chemical analysis, Scanning Electron Microscopy (SEM-EDS) and treatments with HCl, H₂SO₄ and HNO₃ (0.1 M, up to 180 min and 60 ºC). Thermal oxidation permits the separation of SeO₂(g) from a solid residue in the 500-750 ºC range, whereas the adequate combination of soft acid and thermal treatments can be formulated as a potential strategy to separate Agº from a copper (II) solution.