To provide a method for easily leaching a silver from a sulfide containing copper consisting essentially of chalcopyrite, at a low cost without needing a special consideration with respect to the safety environment.
Slurry comprising sulfide containing copper and sulfuric acid containing iron by 30-50 g/L, copper by 10 g/L and preptiser by 0.2-1.0 g/L, is charged into a pressurizing vessel, and the slurry is heated to 120-180°C. Then, the copper and the silver are leached by adjusting an oxidation-reduction potential while adjusting the amount of oxygen and/or air supplied in the gaseous phase part so that the pressure of the gaseous phase part in this pressurizing vessel is made higher by 0.5-2.0 MPa than that in the balanced state, and the silver is precipitated as silver-iron alum, and the copper-leached residue containing this silver-iron alum, is treated with sodium thiosulfate solution and the silver is leached, and the silver in the leached finish solution is adsorbed in activated carbon.
ASANO SATOSHI
TAKEDA KENJI
NAGASE NORIYUKI
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