UF_4氟化反应及其反应动力学

利用自行研制的氟化挥发实验装置,通过UF4和F2之间的气-固反应制备UF6。实验中将傅里叶红外光谱技术用于氟化过程的在线监测,并用XRD和ICP-MS分析方法对反应产物和氟化残余物进行了表征,在此基础上对工艺流程进行了评估。研究表明,氟化反应工艺合理、红外光谱技术在线监测方法可行。研究还表明低温下抽真空的方法能有效除去产物UF6中的HF杂质。利用球形颗粒缩小未反应核模型,对实验数据进行拟合,得到反应温度300℃、氟气体积分数为5%时氟化反应速率常数为0.002 7min-1。

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.