Reducing agent ferrous sulfamate

In the sixties hydrazine stabilized U(IV) solutions, electrochemically produced, successfully substituted the traditional corrosive and salt generating ferrous sulfamate C5) reducing agent for the U/Pu separation (e.g. Eurochemic in Mol, Karlsruhe Reprocessing Plant WAK). 

Solvent from contactor I containing uranyl nitrate and Pu(N03)4 is fed to the center of contactor II. This is refluxed at one end by clean solvent and at the other by a dilute nitric acid solution of a reducing agent strong enough to reduce plutonium to the trivalent form, but not so strong as to reduce uranium from the hexavalent form. Ferrous sulfamate is frequently used. In contactor II plutonium is transferred to the aqueous phase, while uranium remains in the solvent. Solvent from contactor II is fed to one end of contactor III, which is stripped at... 

This principle of oxidizing and reducing plutonium at various stages of the purification scheme has been retained in all subsequent processes. No other element has the same set of redox and chemical properties as plutonium, though some elemoits behave as Pu (o. g-the lanthanides), some like Pu (e,g. zirconium) and some like PuO (e.g. uranium). Numerous redox agents have been used, e.g. K2Cr20y (to PuC " ), NaN02 (to Pu " "), hydrazine, ferrous sulfamate, and U (to Pu "), cf. 16.3. 

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