Method and apparatus for recovering indium from etching waste solution containing indium and ferric chloride

Abstract

An object is to provide a method and an apparatus for recovering indium, the method and apparatus ensuring that it is unnecessary to recover indium in the form of indium hydroxide, indium can be recovered at a high concentration, indium can be recovered easily by a filter or the like without handling inferiors and also, the recovery rate of indium is greatly improved. The method includes adding a precipitation-inducing metal including a metal having higher ionization tendency than indium to an etching waste solution containing at least indium and ferric chloride, in which the concentration of ferric chloride is adjusted to 20% by weight or less to thereby precipitate indium contained in the etching waste solution on the surface of the precipitation-inducing metal, then, detaching the indium precipitated on the precipitation-inducing metal from the precipitation-inducing metal by a detaching means and separating the detached solid indium or indium alloy from the solution to recover the indium.

1 . A method for recovering indium from an etching waste solution containing at least indium and ferric chloride, comprising adding a precipitation-inducing metal including a metal having higher ionization tendency than indium to an etching waste solution with the concentration of ferric chloride of the etching waste solution adjusted to 20% by weight or less in the waste solution to thereby precipitate indium contained in the etching waste solution on the surface of the precipitation-inducing metal, then, detaching the indium precipitated on the precipitation-inducing metal from the precipitation-inducing metal by a detaching means and separating the detached solid indium from the solution to recover the indium. 
     
     
         2 . The method for recovering indium according to  claim 1 , wherein the concentration of ferric chloride in the waste solution is adjusted to 9% by weight or less. 
     
     
         3 . The method for recovering indium according to  claim 1 , wherein the concentration of ferric chloride in the waste solution is adjusted to 6% by weight or less. 
     
     
         4 . The method for recovering indium according to  claim 1 , wherein the precipitation-inducing metal is added to the etching waste solution after the concentration of ferric chloride in the waste solution is adjusted. 
     
     
         5 . The method for recovering indium according to  claim 1 , wherein the precipitation-inducing metal including a metal having higher ionization tendency than indium is any one of zinc and aluminum. 
     
     
         6 . The method for recovering indium according to  claim 1 , wherein the means that detaches indium from the precipitation-inducing metal is a means that oscillates the metal particles by ultrasonic wave. 
     
     
         7 . The method for recovering indium from an etching waste solution containing indium and ferric chloride according to  claim 1 , wherein the precipitation-inducing metal is metal particles having a particle diameter of 0.1 to 8 mm. 
     
     
         8 . An apparatus for recovering indium from an etching waste solution containing at least indium and ferric chloride, comprising a recovering reactor ( 1 ) that introduces an etching waste solution with the concentration of ferric chloride of the etching waste solution adjusted to 20% by weight or less in the waste solution thereinto and adds a precipitation-inducing metal including a metal having higher ionization tendency than indium to cause a metal precipitation reaction to thereby precipitate indium contained in the etching waste solution on the surface of the precipitation-inducing metal, and a detachment means that detaches the indium precipitated on the precipitation-inducing metal from the precipitation inducing metal. 
     
     
         9 . The apparatus for recovering indium according to  claim 8 , further comprising an adjusting vessel ( 2 ) disposed on the upstream side of the recovering reactor ( 1 ) to adjust the concentration of ferric chloride in the waste solution. 
     
     
         10 . An apparatus for recovering indium from an etching waste solution containing at least indium and ferric chloride, comprising a recovering reactor ( 1 ) that introduces an etching waste solution thereinto, adjusts the concentration of ferric chloride in the waste solution to 20% by weight or less and adds a precipitation-inducing metal including a metal having higher ionization tendency than indium to cause a metal precipitation reaction to thereby precipitate indium contained in the etching waste solution on the surface of the precipitation-inducing metal, and a detachment means that detaches the indium precipitated on the precipitation-inducing metal from the precipitation inducing metal. 
     
     
         11 . The apparatus for recovering indium according to  claim 8 , wherein the precipitation-inducing metal including a metal having higher ionization tendency than indium is any one of zinc and aluminum. 
     
     
         12 . The apparatus for recovering indium according to  claim 8 , wherein the means that detaches indium from the precipitation-inducing metal is a means that oscillates the metal particles by ultrasonic wave. 
     
     
         13 . The apparatus for recovering indium according to  claim 10 , wherein the precipitation-inducing metal including a metal having higher ionization tendency than indium is any one of zinc and aluminum. 
     
     
         14 . The apparatus for recovering indium according to  claim 10 , wherein the means that detaches indium from the precipitation-inducing metal is a means that oscillates the metal particles by ultrasonic wave.