| 摘要 |
<p>PURPOSE:To recover efficiently iridium as a hydrochloric acid soln. of a chloride by dissolving and stripping the coating layer of an electrode base body, adding hydrochloric acid thereto, and separating the hydroxide of a heavy metal then making the soln. acidic and passing the soln. through an ion exchange resin. CONSTITUTION:The surface of a used metallic electrode is treated with a molten salt of an alkali metal hydroxide contg. an oxidizing agent, and the coating layer contg. iridium oxide is dissolved and stripped. Water is added thereto after cooling to prepare an aq. soln., and the metal hydroxide of heavy metal formed by neutralization with a hydrochloric acid is separated away. A hydrochloric acid is further added to such aq. soln. to make the soln. acidic and the soln. is brought into contact with a cation exchange resin whereby the alkali metal and residual ion of heavy metal, etc. coexisting therein are removed. Iridium is obtd. as a pure hydrochloric acid soln. by the above-mentioned treatment. The iridium hydrochloric acid soln. of iridium is reusable for producing the metallic electrode, etc.</p> |
