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How does sulfuric acid leaching remove uranium from ore?

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Enrichment of uranium — uranium processing How uranium is enriched to make a nuclear weapon.

Sulfuric acid leaching is a primary method for extracting uranium from ore. For the process to be effective, uranium must be in the hexavalent state; therefore, if the ore contains tetravalent uranium ( $U^{4 +}$ ), oxidizing agents such as manganese dioxide or chlorate ions are added to convert it into the hexavalent uranyl ion ( $U O_{2}^{2 +}$ ).1

Once oxidized, the uranium reacts with sulfuric acid to form a soluble uranyl sulfate complex anion, $[U O_{2} (S O_{4})_{3}]^{4 -}$ . This reaction typically occurs by agitating the ore-leach mixture for 4 to 48 hours at ambient temperature, maintaining a final pH of approximately 1.5.1

After the uranium has been dissolved into the leach liquor, it must be separated from the remaining ore solids. The resulting solution is then processed to recover the uranium, commonly using ion-exchange resins or solvent extraction techniques, depending on the concentration of uranium present in the leachate.2