AUC(ammonium uranylcarbonate) 분말의 배소·환원에 대한 연구를 수소분위기에서 TG-DTA를 사용하여 수행하였다. AUC 분말의 열분해 과정 중 다양한 상 변화 특성을 XRD로 확인하였다. AUC 분말의 열분해 반응 메카니즘은 (NH4)4[UO2(CO3)3]→UO3+3CO2+4NH3+2H2O 3UO3+H2→U3O8+H2O U3O8+H2→3UO2+H2O 와 같은 3단계로 나타났다. AUC 분말의 배소·환원 속도는 비등온 열중량법으로 구하였으며, 데이터해석은 Osawa 방법과 Zsako 방법으로 구하였는데 다음과 같다.
Reaction
Mechanusm
E(Kcal/mole)
AUC→UO3
2nd nucleation and growth
19.5
UO3→U3O8
3nd nucleation and growth
30.12
U3O8→UO2
4th nucleation and growth
31.43
Calcination and reduction of AUC(ammonium uranylcarbonate) have been carried out by using TG-DTA in H2 atmosphere. Phases of various intermediates obtained during thermal analysis of AUC were confirmed by XRD. As results, AUC was calcined and reduced by three steps as follows; (NH4)4[UO2(CO3)3]→UO3+3CO2+4NH3+2H2O 3UO3+H2→U3O8+H2O U3O8+H2→3UO2+H2O The calcination and reduction kinetics of AUC have been also determined by non-isothermal method and the analysis of kinetic data was made by Osawa and Zsako methods. The results were as follows;