Recovery Method for High Purity Platinum

Abstract

A high purity platinum recovery method including the steps of dissolving a platinum alloy containing ruthenium in aqua regia and eliminating residue, thereafter causing acid with platinum dissolved therein and an ammonium chloride solution to react so as to deposit chloroplatinic ammonium salt, and reducing the chloroplatinic ammonium salt to obtain a platinum sponge. The method is characterized in that acid with platinum dissolved therein and the ammonium chloride solution are caused to react at a temperature of 40° C. or higher. Provided is a method which enables recovery, at a high yield, of high purity platinum which can be reused in a platinum and a platinum-containing target as a result of efficiently eliminating ruthenium, cobalt, chromium, copper, iron, nickel, silicon and the like which become included in a spent platinum alloy sputtering target, particularly a magnetic material target, and in scraps such as mill ends, sawdust, and surface grinding scraps generated during the production process of such a target.

1 . A high purity platinum recovery method including the steps of dissolving a platinum alloy containing ruthenium in aqua regia and eliminating residue, thereafter causing acid with platinum dissolved therein and an ammonium chloride solution to react so as to deposit chloroplatinic ammonium salt, and reducing the chloroplatinic ammonium salt to obtain a platinum sponge, wherein the acid with platinum dissolved therein and the ammonium chloride solution are caused to react at a temperature of 40° C. or higher, wherein a platinum concentration of a liquid resulting from dissolving the platinum alloy containing ruthenium in the aqua regia is 15 g/L or more, and wherein a ruthenium concentration of the liquid resulting from dissolving the platinum alloy containing ruthenium in the aqua regia is 6 g/L or less. 
     
     
         2 - 3 . (canceled) 
     
     
         4 . The high purity platinum recovery method according to  claim 1 , wherein a ruthenium content as an impurity in the platinum sponge obtained by roasting the chloroplatinic ammonium salt is 2% or less. 
     
     
         5 . The high purity platinum recovery method according to  claim 4 , wherein the ruthenium content is 1% or less. 
     
     
         6 . The high purity platinum recovery method according to  claim 5 , wherein the platinum alloy containing ruthenium is scrap of a magnetic material target, and a platinum recovery rate from the scrap is 99% or higher. 
     
     
         7 . The high purity platinum recovery method according to  claim 4 , wherein the platinum alloy containing ruthenium is scrap of a magnetic material target, and a platinum recovery rate from the scrap is 99% or higher. 
     
     
         8 . The high purity platinum recovery method according to  claim 1 , wherein the platinum alloy containing ruthenium is scrap of a magnetic material target, and a platinum recovery rate from the scrap is 99% or higher.