Metal electrowinning anode and electrowinning method

Abstract

An electrowinning system is provided that is capable of suppressing accumulation of a side reaction product on an anode and a rise of an electrolysis voltage caused thereby, and an electrowinning method is provided using the system. To solve this problem, the electrowinning system of the present invention applies predetermined electrolysis current between an anode and a cathode placed in an electrolyte, thereby depositing a desired metal on the cathode, in which the electrolyte is a sulfuric acid-based or chloride-based solution containing ions of the metal, and the anode has a catalytic layer, containing amorphous iridium oxide or amorphous ruthenium oxide, formed on a conductive substrate.

What is claimed is: 
     
         1 . A nickel electrowinning method comprising:
 contacting an anode with a chloride-based electrolyte containing nickel ions; and   extracting nickel from the electrolyte,   wherein the anode comprises a conductive substrate and a catalytic layer formed on the conductive substrate, and the catalytic layer is a composite oxide of amorphous ruthenium oxide and amorphous titanium oxide.   
     
     
         2 . The nickel electrowinning method according to  claim 1 , wherein the anode further comprises an intermediate layer made of tantalum or a tantalum alloy, and the intermediate layer is formed between the conductive substrate and the catalytic layer. 
     
     
         3 . The nickel electrowinning method according to  claim 1 , wherein the catalytic layer is a composite oxide of 25 to 35 at. % of amorphous ruthenium oxide in terms of metal and 75 to 65 at. % of amorphous titanium oxide in terms of metal. 
     
     
         4 . The nickel electrowinning method according to  claim 2 , wherein the catalytic layer is a composite oxide of 25 to 35 at. % of amorphous ruthenium oxide in terms of metal and 75 to 65 at. % of amorphous titanium oxide in terms of metal. 
     
     
         5 . The nickel electrowinning method according to  claim 1 , further comprising:
 forming a cathode along with the anode,   wherein the cathode comprises a zinc plate.   
     
     
         6 . A nickel electrowinning method comprising:
 contacting an anode with a chloride-based electrolyte containing nickel ions; and   extracting nickel from the electrolyte,
 wherein the anode comprises a conductive substrate and a catalytic layer formed on the conductive substrate, and the catalytic layer is a composite oxide of completely amorphous ruthenium oxide and completely amorphous titanium oxide. 
   
     
     
         7 . The nickel electrowinning method of  claim 6 , wherein the catalytic layer consists of only completely amorphous ruthenium oxide and completely amorphous titanium oxide.