Effect of feed acidity, stirring, time and temperature on the extraction stripping process of uranium-molybdenum

Uranium-molybdenum (UMo) is a candidate of research reactor fuel that has been well developed in the world. The manufacturing process may encounter many failures, both failures in powder production of UMo/Al and fabrication process. The purpose of this experiment is to recover rejected UMo for reuse as fuel. The initial stage was dissolving the rejected products, i.e. the powder form, the core fuel element and fuel element plate of UMo/Al, with NaOH in order to obtain a solution of NaAlO₂ and residual UMo with impurities. The residual UMo with impurities was dissolved in concentrated nitric acid to obtain a solution of a mixture of UO₂(NO₃)₂ and MoO₂(NO₃)₂ with impurities. Extraction-stripping is considered as an appropriate method to collect and refine the UMo. As extractors, TBP, kerosene, dodecane were used. In the process of extraction, uranium and molybdenum enters the organic phase of TBP, while the impurities are in the water phase (raffinate). Uranium and molybdenum in the organic phase are stripped with hot water (as a parameter), resulting a solution of a mixture of refined UO₂(NO₃)₂ and MoO₂(NO₃)₂. The parameters studied in the extraction process are time, stirring speed, and the acidity of the feed, whereas the parameter for stripping is temperature. The optimum extraction condition obtained is acidity at 3N and stirring at 200 rpm for 50 minutes. In this condition, extracting process efficiency is 66.48%, while the stripping efficiency of 37.08% is reached at a temperature of 60 °C. (author)