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Search / Korean Journal of Chemical Engineering
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HWAHAK KONGHAK, Vol.37, No.1, 14-20, 1999
비등온 열중량법에 의한 AUC분말의 열분해 특성해석
Thermal Decomposition Characteristics of AUC Powder by Non-Isothermal Method
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 (NH 4) 4[UO 2(CO 3) 3]→UO 3+3CO 2+4NH 3+2H 2O 3UO 3+H 2→U 3O 8+H 2O U 3O 8+H 2→3UO 2+H 2O 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) |
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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 H 2 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; (NH 4) 4[UO 2(CO 3) 3]→UO 3+3CO 2+4NH 3+2H 2O 3UO 3+H 2→U 3O 8+H 2O U 3O 8+H 2→3UO 2+H 2O 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; Reaction | Mechanusm | E(Kcal/mole) |
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AUC→UO3 | 2nd nucleation and growth | 19.5 | UO3→U3O8 | 3nd nucleation and growth | 30.12 | U3O8→UO2 | 4th nucleation and growth | 31.43 |
[References]
- 원자력 장기발전 종합계획(2차 시안), 과학기술처, 1990
- Wacklington JS, Raven LF, Thorpe, Br. Nucl. Energy Soc., 18, 283, 1979
- Kim BK, Chang IS, Hwang ST, Park JH, Kim EH, Park JJ, Choi CS, Chem. Ind. Technol., 9, 373, 1991
- Assmann H, Doerr W, "Ceramic Powders," Material Science Monographs 16, Elsevier, 707, 1983
- Assmann H, Bairiot H, IAEA Tech. Report Ser., No. 221, 149, 1983
- Chang IS, Proceedings of the 2nd Korea-Japan Symposium on Separation Technology, Seoul, 519, 1990
- Halldahl L, Nygrem M, J. Nucl. Mater., 138, 99, 1986
- Corfunke EHP, "The Chemistry of Uranium," Elsevier Pub. Co., 1969
- Friedman HL, Polym. Lett., 7, 41, 1969
- Freeman ES, Carroll B, J. Phys. Chem., 62, 394, 1958
- Doyle CD, J. Appl. Polym. Sci., 15, 285, 1961
- Zsako J, J. Phys. Chem., 72(7), 2406, 1968
- Ozawa T, Bull. Chem. Soc. Jpn., 38, 1881, 1965
- Ge Q, Kang S, Thermochim. Acta, 116, 71, 1987
- Kim EH, Park JJ, Park JH, Chang IS, Choi CS, Kim SD, J. Nucl. Mater., 209, 294, 1994
- Halldahl L, Toft Sorensen O, Proc. 6th Int. Conf. on Thermal Analysis, Bayrath, Germany, 499, 1980
- Notz, Mendel, J. Inorg. Nucl. Chem., 14, 55, 1960
- DeMarco, Mendel, J. Phys. Chem., 64, 132, 1960
- Sheila A, Trans. Faraday Soc., 57, 1400, 1961
- Dell, Wheeler, Trans. Faraday Soc., 58, 485, 1962
- Le Page, France, J. Inorg. Nucl. Chem., 36, 87, 1974
- Tompkims FC, "Treatise on Solid State Chemistry," ed. N.B. Hannay, Plenum Press, New York, 4, 1983
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