Process for the extraction of a by-product metal from a mineral concentrate||Process for the extraction of a by-product metal from a mineral concentrate

It is provided a process for the extraction of a by-product metal from a mineral concentrate comprising a sulfide, selenide, or telluride mineral of the Cu-Ag-Au group, the process comprising the steps of: a) providing a mineral concentrate comprising a sulfide, selenide, or telluride mineral of the Cu-Ag-Au group comprising by-product metals; b) contacting the mineral concentrate with a leaching solvent system comprising i) a deep eutectic solvent (DES) consisting of a mixture of a hydrogen bond acceptor (HBA) of Cat+X- and a hydrogen bond donor (HBD) selected from ethylene glycol, triethylene glycol, and glycerol in a HBA:HBD molar ratio from 1:10 to 10:1; and ii) an additive selected from the H2O2, a strong inorganic acid, and a mixture thereof; in order to obtain a leachate containing the by-product metal in dissolution; c) separating the leachate from the undissolved mineral concentrate; and d) optionally, recovering the by-product metal from the leachate. It is also provided a leaching solvent.