Method for producing indium-containing aqueous solution

Abstract

As an effective method for reusing ITO sintered bodies, there is provided a method for producing an aqueous solution containing indium ions which comprises a step of subjecting an acidic solution containing indium ions and tin ions to an electrolytic treatment to precipitate metallic tin and a step of removing or re-dissolving the precipitated metallic tin.

1 . A method for producing an aqueous solution containing indium ions which comprises a step of subjecting an acidic solution containing indium ions and tin ions to an electrolytic treatment to precipitate metallic tin and a step of removing or redissolving the precipitated metallic tin.  
     
     
         2 . A method according to  claim 1 , wherein the current quantity for the electrolytic treatment is a quantity with which the tin ions can be substantially precipitated from the acidic solution by converting the tin ions to metallic tin; and the precipitated metallic tin is removed.  
     
     
         3 . A method according to  claim 2 , wherein the current density in the electrolytic treatment is not less than 50 Am −2  and not more than 800 Am −2 .  
     
     
         4 . A method according to  claim 1 , wherein the acidic solution contains indium ions and tetravalent tin ions and the content of the tetravalent tin ions exceeds 50% by weight in the total tin ions; the current quantity for the electrolytic treatment is half or more of the current quantity with which tetravalent tin ions can be precipitated as metallic tin so that the content of divalent tin ions reaches 50% by weight or more in the total tin ions; and the precipitated metallic tin is redissolved.  
     
     
         5 . A method according to  claim 4 , wherein the current density in the electrolytic treatment is not less than 50 Am −2  and not more than 2000 Am −2 .  
     
     
         6 . A method according to  claim 1 , wherein the electrolytic treatment is carried out by passing a current through an aqueous sulfuric acid solution in an anode chamber of an electrolytic cell and an acidic solution containing indium ions and tin ions in a cathode chamber of the electrolytic cell which are partitioned with a cation exchange membrane.  
     
     
         7 . A method according to  claim 1 , wherein the acidic solution containing indium ions and tin ions is obtained by dissolving a compound containing indium, tin and oxygen in hydrochloric acid.