Thermogravimetric study of the reaction of uranium oxides with fluorine
Thermogravimetric study of the reaction of uranium oxides with fluorine
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铀氧化物与氟反应的热重研究
DOI：
10.1016/j.jallcom.2007.04.099
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发表时间：
2008
影响因子：
6.2
通讯作者：
O. Tochiyama
中科院分区：
文献类型：
--
作者：
Motohiro Komura;N. Sato;A. Kirishima;O. Tochiyama
采用TG-DTA方法，采用防腐型差示热天平，对铀氧化物与氟的反应进行了热重研究。当 UO2 从 R.T. 加热时在 5% F2/He 气氛中升至 500°C，重量增加约出现在 100°C 左右。 250°C 有放热峰。然后重量略有下降，并出现一个小放热峰，随后完全挥发，在约 100 处出现一个大放热峰。 350°C。在15、30、60mlmin−1的流速下，UO2的氟化似乎没有显着变化。在1、2、5和10°Cmin−1的不同加热速率下，随着加热速率的增加，氟化峰向更高的温度移动。为了与热重分析结果进行比较，采用 XRD 方法对不同温度下获得的产物进行物相分析。在260℃时，产物为UO2和少量中间体化合物UO2F。该化合物的量随着温度升高至 320°C 而增加。然后在340℃出现另一相UO2F2，但它立即被氟化为挥发性氟化物。当使用U3O8作为起始材料时，发现陡峭的重量减少峰出现在约。 350℃，铀完全挥发。该结果表明 U3O8 在此温度下发生氟化，形成 UF6。三氧化铀表现出与 U3O8 相似的氟化行为。
Thermogravimetric study of the reaction of uranium oxides with fluorine was conducted by TG-DTA method using anti-corrosion type differential thermobalance. When UO2was heated from R.T. to 500°C in 5% F2/He atmosphere, the weight increase appeared at ca. 250°C with an exothermic peak. Then the weight decreased slightly with a small exothermic peak followed by the complete volatilization with a large exothermic peak at ca. 350°C. At a flow rate of 15, 30, 60mlmin−1, there seemed to be no significant change for the fluorination of UO2. With the different heating rates of 1, 2, 5 and 10°Cmin−1, the fluorination peak shifted to higher temperature with increasing heating rates. For the comparison with thermogravimetric results, phase analysis by XRD method was conducted for the products obtained at different temperatures. At 260°C, the product was UO2with a small amount of the intermediate compound, UO2F. The amount of this compound increased with increasing temperature up to 320°C. Then another phase of UO2F2appeared at 340°C but it was immediately fluorinated to the volatile fluoride. When U3O8was used as a starting material, it was found that the steep weight decrease peak appeared at ca. 350°C and the uranium volatilized completely. This result suggests that fluorination of U3O8occurs at this temperature forming UF6. Uranium trioxide showed the similar fluorination behavior to that of U3O8.