Patent ID: 7785395

Claim:
A method for the recovery of gold from a sulphidic concentrate, comprising: leaching the sulphidic concentrate in a first leaching in atmospheric conditions using an aqueous leaching solution comprising alkali chloride-copper (II) chloride; regulating the potential of the leaching solution to be at least 600 mV Ag/AgCl at the end of leaching; separating a leachate solution containing dissolved gold from leaching precipitate remaining undissolved in the first leaching; and recovering the dissolved gold from the first leachate solution; physically separating the precipitate remaining undissolved in the first leaching into fine material comprising elemental sulphur and a majority of iron oxides and arsenic oxides present in the leaching remaining undissolved in the first leaching and a gold-containing first intermediate product which comprises pyrites, arsenopyrite and coarse gangue minerals; separating coarse, undissolved gold from the gold-containing first intermediate product using gravity separation to form a gold-containing product and a fraction containing pyrite and gangue minerals; comminuting the fraction containing pyrite and gangue minerals to form a second intermediate product; leaching the second intermediate product in a second leaching to form a leachate solution containing the pyrite and arsenopyrite and a gold-containing residue returning the gold-containing residue to the first leaching or to said recovering the dissolved gold from the first leachate solution.