Analytical Sciences

Extraction of Uranium from Simulated Ore by the Supercritical Carbon Dioxide Fluid Extraction Method with Nitric Acid-TBP Complex

Le Thi Kim DUNG,* Tomoki IMAI,** Osamu TOMIOKA,** Mikio NAKASHIMA,** Kuniaki TAKAHASHI,** and Yoshihiro MEGURO**

*Radioactive Ore Processing Technology, Institute for Technology of Radioactive and Rare Elements, Vietnam Atomic Energy Commission, 48 Lang Ha Street, Dong Da, Hanoi, Vietnam
**Nuclear Cycle Backend Directorate, Japan Atomic Energy Agency, 2-4 Shirakatashirane, Tokai, Ibaraki 319-1195, Japan

The supercritical fluid extraction (SFE) method using CO₂ as a medium with an extractant of HNO₃-tri-n-butyl phosphate (TBP) complex was applied to extract uranium from several uranyl phosphate compounds and simulated uranium ores. An extraction method consisting of a static extraction process and a dynamic one was established, and the effects of the experimental conditions, such as pressure, temperature, and extraction time, on the extraction of uranium were ascertained. It was found that uranium could be efficiently extracted from both the uranyl phosphates and simulated ores by the SFE method using CO₂. It was thus demonstrated that the SFE method using CO₂ is useful as a pretreatment method for the analysis of uranium in ores.

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