高分散态铀氧化物对硝酸钾热分解的催化作用

Catalytic Effect of Highly Dispersed State Uranium Oxides on the Thermal Decomposition of Potassium Nitrate

以SBA-15为载体,通过水热法制得高分散态的铀氧化物,而后引入KNO_(3)。基于程序升温分解-质谱(temperature programmed decomposition-mass spectrometry,TPDE-MS)联用技术,研究了KNO_(3)的热分解行为。利用KAS(Kissinger-Akahira-Sunose)方法和F 1/3方法分析了KNO_(3)热分解数据,得出相应的动力学参数。结果表明:纯KNO_(3)在600℃左右开始发生分解,分解率位于0.5~0.8时,其分解反应符合F 1/3方法模型函数,反应活化能为285 kJ/mol;高分散态铀氧化物上,KNO_(3)分解温度降低至200℃,分解活化能在205.4~207.3 kJ/mol之间。铀氧化物对KNO_(3)具有良好的催化活性,采用KAS和F 1/3方法得到KNO_(3)热分解的平均活化能分别降低了30和74 kJ/mol。

High Dispersed Uranium oxides were obtained by hydrothermal method using SBA-15 as a carrier,and later introduced KNO_(3).Thermal decomposition behavior of KNO_(3) was studied based on the(temperature programmed decomposition-mass spectromer,TPDE-MS).The thermal decomposition data of KNO_(3) were analyzed using KAS method and F 1/3 method,and the corresponding kinetic parameters were derived.The results show that the decomposition of pure KNO_(3) starts to occur at about 600℃,and when the decomposition rate lies in the range of 0.5-0.8,the decomposition reaction conforms to the model function of the F 1/3 method,with a reaction activation energy of 285 kJ/mol;on the high dispersed uranium oxides,the decomposition temperature of KNO_(3) decreases to 200℃,and the decomposition activation energy is in the range of 205.4-207.3 kJ/mol.Uranium oxides have good catalytic activity for KNO_(3),resulting in a reduction of the average activation energy of thermal decomposition of KNO_(3) was reduced by 30 and 74 kJ/mol using KAS and F 1/3 mothods,respectively.