This study was performed to produce and characterize ammonium uranyl nirate(AUN) as well as to investigate their thermal decomposition. AUNs were prepared from the reaction of UO2(NO3)2 solution with NH4NO3 solution. AUNs produced, by varing experimental conditions of pH of reaction solution and mole ratio of U to NH4(+), were (NH4)2UO2(NO3)4·2H2O and NH4UO2(NO3)3 and these were confirmed as by TG/DTA analysis, chemical analysis, elementary analysis, X-ray diffraction analysis and infrared spectroscopy. (NH4)2UO2(NO3)4·2H2O was formed when the mole ratio of NH4(+) to U was 2.14 and the pH of UO2(NO3)2-NH4NO3 solution was 2.58 NH4UO2(NO3)3 was formed when the mole ratio of U to NH4(+) was 1.07 and pH of UO2(NO3)2-NH4NO3 solution was 2.01. The thermal decomposition paths of two AUNs were as follows: (NH4)2UO2(NO3)4·2H2O→(NH4)2UO2(NO3)4→NH4UO2(NO3)3→UO3, NH4UO2(NO3)3→UO3.

본 연구에서는 ammonium uranyl nitrate(AUN)를 합성하여 특성화하였고 이들의 열분해 특성을 살펴보았다. AUN은 NH4NO3와 UO2(NO3)2·2H2O의 두가지 형태의 복염으로 존재함이 TG/DTA분석, 화하 및 원소분석, X-선 회절분석, 그리고 적외선 분광분석에 의하여 확인되었다. 반응용액의 pH가 2.58, NH4(+)/U의 몰비가 2.14에서 (NH4)2UO2(NO3)4·2H2O가, 그리고 pH가 2.01, NH4(+)/U의 몰비가 1.07에서 NH4UO2NO3가 생성되었다. AUN들은 (NH4)2UO2(NO3)·2H2O→(NH4)2UO2(NO3)4→NH4UO2(NO3)3→UO3, NH4UO2(NO3)3→UO3의 경로를 거치면서 각각 열분해되었다.