Method of removing oxide film on surface of copper or copper-base alloy and copper or copper-base alloy recovered using the method

A method of removing oxide film formed on a surface of a copper or copper-base alloy, the method comprising steps of:

• dipping a copper or copper-base alloy having oxide film formed on a surface thereof, to remove the oxide film, in a pickling bath which contains a pickling solution including:
• 50 g/L to 400 g/L of sulfuric acid;
• 1 g/L to 100 g/L of at least one oxidant selected from a group consisting of nitric acid, hydrogen peroxide, peroxodisulfate ions, and iron (III) ions;
• 0.01 g/L to 10 g/L of at least one additive selected from a group consisting of aromatic sulfonic acid, aromatic sulfonate, alkylamine, aromatic carboxylic acid, and aromatic carboxylate;
• 0.005 g/L to 10 g/L of at least one surfactant selected from a group consisting of alkylbenzene sulfonic acid and alkylbenzene sulfonate;
• and
• 10 g/L to 300 g/L of copper sulfate;
• electrolyzing the pickling solution containing the removed oxide film in an electrolytic bath so as to recover a copper or copper-base alloy from the oxide film;
• adding the oxidant, the additive, and the surfactant to the electrolyzed pickling solution in amounts equivalent to those consumed when the oxide film is removed and when the electrolysis is performed;
• and
• returning the electrolyzed pickling solution, to which the oxidant, the additive, and the surfactant are added, to the pickling bath to be reused as a new pickling solution.