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

Abstract

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, is used to remove oxide film, and then reused by being electrolyzed and adding the oxidant, the additive and the surfactant in amounts equivalent to consumed amounts.

What is claimed is: 
     
         1 . 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.   
     
     
         2 . The method of removing oxide film on a surface of a copper or copper-base alloy according to  claim 1 ,
 wherein a surface tension of the pickling solution is less than or equal to 50×10 −3  N/m.   
     
     
         3 . The method of removing oxide film on a surface of a copper or copper-base alloy according to  claim 1 , further comprising steps of:
 in the electrolyzing step, adjusting a concentration of copper ions in the pickling solution containing the removed oxide film is 20 g/L to 60 g/L;   controlling a current density in a range of 1 A/dm 2  to 25 A/dm 2 ; and   rotating a cathode having a cylindrical body at a peripheral speed in a range of 0.08 m/s to 0.48 m/s.   
     
     
         4 . The method of removing oxide film on a surface of a copper or copper-base alloy according to  claim 2 , further comprising steps of:
 in the electrolyzing step, adjusting a concentration of copper ions in the pickling solution containing the removed oxide film is 20 g/L to 60 g/L;   controlling a current density in a range of 1 A/dm 2  to 25 A/dm 2 ; and   rotating a cathode having a cylindrical body at a peripheral speed in a range of 0.08 m/s to 0.48 m/s.   
     
     
         5 . The method of removing oxide film on a surface of a copper or copper-base alloy according to  claim 3 ,
 wherein in the electrolyzing, the flow rate of the pickling solution supplied to the electrolytic bath and the current density in the electrolytic bath are adjusted such that the concentration of copper ions in the pickling solution containing the removed oxide film is 20 g/L to 60 g/L.   
     
     
         6 . The method of removing oxide film on a surface of a copper or copper-base alloy according to  claim 4 ,
 wherein in the electrolyzing, a flow rate of the pickling solution supplied to the electrolytic bath is adjusted such that a concentration of copper ions in the pickling solution containing the removed oxide film is 20 g/L to 60 g/L.   
     
     
         7 . A copper or copper-base alloy which is recovered using the method of removing oxide film on a surface of a copper or copper-base alloy according to  claim 1  and is capable of being used as a recycled material.