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

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.