Editing Neptunium (section)

===Purification methods===
Recovering uranium and plutonium from spent nuclear fuel for reuse is one of the major processes of the [[nuclear fuel cycle]]. As it has a long half-life of just over 2&nbsp;million years, the [[alpha decay|alpha emitter]] <sup>237</sup>Np is one of the major isotopes of the [[minor actinide]]s separated from spent nuclear fuel.<ref name="Yoshida7045">Yodshida et al., pp. 704–5.</ref> Many separation methods have been used to separate out the neptunium, operating on small and large scales. The small-scale purification operations have the goals of preparing pure neptunium as a [[precursor (chemistry)|precursor]] of metallic neptunium and its compounds, and also to isolate and preconcentrate neptunium in samples for analysis.<ref name="Yoshida7045" />

Most methods that separate neptunium ions exploit the differing chemical behaviour of the differing oxidation states of neptunium (from +3 to +6 or sometimes even +7) in solution.<ref name="Yoshida7045" /> Among the methods that are or have been used are: solvent [[extraction (chemistry)|extraction]] (using various [[extractant]]s, usually [[denticity|multidentate]] β-diketone derivatives, [[organophosphorus compound]]s, and [[amine]] compounds), [[chromatography]] using various [[ion exchange|ion-exchange]] or [[chelation|chelating]] resins, [[coprecipitation]] (possible [[matrix (chemical analysis)|matrices]] include [[lanthanum(III) fluoride|LaF<sub>3</sub>]], [[bismuth phosphate|BiPO<sub>4</sub>]], [[barium sulfate|BaSO<sub>4</sub>]], [[iron(III) hydroxide|Fe(OH)<sub>3</sub>]], and [[manganese(IV) oxide|MnO<sub>2</sub>]]), [[electroplating|electrodeposition]], and [[biotechnology|biotechnological]] methods.<ref name="Yoshida70517">Yoshida et al., pp. 705–17.</ref> Currently, commercial reprocessing plants use the Purex process, involving the solvent extraction of uranium and plutonium with [[tributyl phosphate]].<ref name="Yoshida710">Yoshida et al., p. 710.</ref>