Ore is leached with sulfuric acid or sodium carbonate to yellowcake (U3O8), then purified by solvent extraction, calcined to UO3 and UO2, and either pelleted for reactor fuel or fluorinated to UF6 for enrichment.
Research Elements U · atomic number 92 Actinide · period 7 [Rn] 5f3 6d1 7s2 Shells: 2, 8, 18, 32, 21, 9, 2 Valence electrons: 2 in the outer shell (7s2), and 4 in 5f3 6d1 Green dots are the outer shell's s and p electrons. Softer green dots are the d electrons of transition metals, and the d and f electrons of lanthanides and actinides: they often take part in bonding, but not always. Grey dots are the core. Ground-state configuration from the NIST Atomic Spectra Database (A. Kramida, Yu. Ralchenko, J. Reader and the NIST ASD Team). Abundance is the mole fraction of the element found as that isotope on Earth; digits in parentheses are the uncertainty in the last digits. Masses and abundances from NIST, Atomic Weights and Isotopic Compositions (J. S. Coursey, D. J. Schwab, J. J. Tsai and R. A. Dragoset, National Institute of Standards and Technology).Uranium
Electrons
How it's obtained
Natural isotopes
Isotope Relative atomic mass Abundance How this isotope is separated 234U 234.0409523(19) 0.000054(5) A trace in natural U; not separated on its own but co-enriched with ²³⁵U in the centrifuge cascade because its mass is close to ²³⁵U. 235U 235.0439301(19) 0.007204(6) Gas centrifuges spin UF6 at ~500 m/s in cascades of thousands of machines; the heavier ²³⁸UF6 migrates outward, and the ²³⁵UF6-richer fraction is drawn from the axis and cascaded upward. Historic route: gaseous diffusion of UF6 through porous nickel barriers, which needed vastly more electricity. 238U 238.0507884(20) 0.992742(10) The bulk of natural U, and the depleted-U tails left by centrifuge enrichment; the tails are stored as UF6 or converted to U3O8 and used for shielding and armor-piercing rounds.