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

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, wherein the sulfide, selenide, or telluride mineral comprises a by-product metal selected from the group consisting of Bi, Ag, Te, Se, Sb, Cd, In, Au, Ge, Co, Pt, Mo, and mixtures thereof;
• 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 formula (I)
• wherein
• Cat+ is a cation selected from the group consisting of (2-hydroxyethyl)trimethylammonium (choline, Ch), ethyl(2-hydroxyethyl)dimethylammonium, benzyl(2-hydroxyethyl)dimethylammonium, bis(2-hydroxyethyl)dimethylammonium, benzyl-bis(2-hydroxyethyl)methylammonium, methyl(2-hydroxyethyl)diethyl-ammonium, (2-chloroethyl)trimethylammonium;
• and X− is an anion selected from the group consisting of F−, Cl−, Br− and I−;
• and
• a hydrogen bond donor (HBD) selected from ethylene glycol, triethylene glycol and glycerol;
• wherein the HBA and the HBD are in a molar ratio from 1:10 to 10:1;
• and
• ii) an additive selected from the group consisting of H2O2, a strong inorganic acid, and a mixture of H2O2 and the strong inorganic acid;
• in order to obtain a leachate containing the by-product metal in dissolution;
• and
• c) separating the leachate from the undissolved mineral concentrate.