| 摘要 |
PROBLEM TO BE SOLVED: To efficiently separate Pd and Cs by first bringing coppery insoluble hexacyanoferrate (II), oxidation-treated substance thereof, or copper hexacyanoferrate (III) into contact with an acidic solution of nitric acid to absorptively separate Pd selectively. SOLUTION: A material consisting of oxidation-treated substance of coppery insoluble hexacyanoferrate (II) or copper hexacyanoferrate (III), by which Pd is adsorbed and supported under the condition that no nitrous acid is allowed to coexist, is subjected to reduction treatment. A solution, from which Pd is removed, is brought into contact with the above material, by which Cs is absorptively separated selectively. The absorbent, which is made to adsorb Cs, is subjected to oxidation treatment using a nitric acid solution containing nitrous acid, by which Cs is desorbed. The adsorbent, from which Cs is desorbed, is subjected to reduction treatment and reclaimed as a Cs adsorbent. It is preferable that contact time with the acidic solution of nitric acid for Pd separation is regulated to >=48 hr. Moreover, it is desirable to add hydrazine, sulfamic acid, etc., as antioxidant in order to produce the maximum Pd adsorptivity of coppery insoluble hexacyanoferrate (II).
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