Fluorination of UF₄ and Its Reaction Kinetics

The gas-solid reaction of uranium tetrafluoride (UF₄) with fluorine (F₂) resulting uranium hexafluoride (UF₆) has been investigated using self-developed fluoride volatility equipment. In this study, the Fourier transform infrared spectroscopy (FTIR) was used for in-situ monitoring of fluorination process, while X-ray diffraction (XRD) and inductively coupled plasma-mass spectrometry (ICP-MS) to characterize the reaction product and the residue. Based on the analytical data, the process designed for recovery of uranium by fluo-ride volatility was evaluated. The results show that the fluorination process, and the in-situ monitoring of process by FTIR are feasible. In addition, the hydrogen fluoride (HF) as an impurity in the product is removed effectively by vacuuming at low temperature. The kinetic data indicates that the rate constant of fluorination reaction is 0.0027 min^-1 at 300℃ and 0.2 L/min φ=5% F₂ by fitting the experimental data using the shrinking core model of spherical particles.