Patent ID: 8388730

Claim:
A process of leaching gold comprising the steps of: a) leaching copper from copper sulfide ore material that contains gold or contains silicate ore containing gold until the copper grade is reduced to 7.9 wt % or less; b) mixing the resulting material having a copper grade of 7.9 wt % or less with a gold leaching solution selected from the group consisting of a first solution containing chloride ions and ferric ions, and a second solution containing chloride ions and iron ions, the iron ions having been oxidized to trivalent ferric ions by air bubbled into the second solution; and c) adjusting the pH of the gold leaching solution to 1.9 or less with stirring to leach at least gold in the material after step b) into the gold leaching solution by the oxidative activity of the ferric ions contained in the gold leaching solution, wherein the concentration of gold is reduced by selectively removing gold from part or all of the gold leaching solution by adding activated carbon to the gold leaching solution during gold leaching, and optionally adding lead nitrate.