Britannica Sources used in this answer

How is uranium recovered from low-grade ores using anion-exchange resin?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

chemical structure of cation exchanger — ion-exchange reaction Figure 1: Chemical structure of cation exchanger. The exchangeable ions are marked ⁺. The whole structure is permeated by solvent molecules, usually water (not shown).

Uranium is recovered from low-grade ores through a process involving leaching and subsequent ion exchange. First, the ore is leached using either acidic or alkaline solutions to dissolve the uranium, ensuring it is in the hexavalent state to form soluble complex ions, such as the uranyl sulfate complex [UO $_{2}$ (SO $_{4}$ ) $_{3}$ ] $^{4 -}$ or the uranyl carbonate complex [UO $_{2}$ (CO $_{3}$ ) $_{3}$ ] $^{4 -}$ .12

Once the leach liquor is clarified, these negatively charged uranium complex ions are sorbed onto anion-exchange resins. This method is highly selective, allowing for the separation of uranium from other metals like iron. The resins are utilized in various industrial configurations, such as fixed-bed, moving-bed, or resin-in-pulp systems.23

After the uranium has been captured by the resin, it is recovered through a process called elution. Conventionally, this is achieved using solutions of sodium or ammonium chloride or nitrate. In some specific applications, dilute nitric acid is used to remove the uranium from the resin.23