Nuclear Chemical Engineering Techniques for Thermochemical Reactions: Uranyl Nitrate Pyrolysis Process
JIANG Zhe1, WANG Yi1, XIN Cuncun2, WU Haoyang3, LI Dabo1
1. China Nuclear Power Engineering Company Limited, Beijing 100840, China;
2. Peking University, Beijing 100840, China;
3. University of Science and Technology Beijing, Beijing 100840, China
Abstract：The sustainable development of nuclear energy holds strategic significance for alleviating environmental pressures and reducing carbon emissions. As a pivotal intermediate in the nuclear fuel cycle, the industrial production of uranium trioxide (UO3) predominantly relies on thermal decomposition processes of uranyl salts, such as uranyl nitrate hexahydrate (UNH), ammonium diuranate (ADU), and ammonium uranyl carbonate (AUC). This review systematically summarizes the research progress on the thermal decomposition mechanisms of uranyl salt and engineered denitration technologies. Research indicates that the thermal decomposition pathways of different uranyl salts are significantly influenced by crystalline structure, atmospheric conditions, and temperature modulation. For instance, UNH exhibits distinct single- or multi-stage decomposition behaviors under vacuum and air, yielding UO3 and its hydrated form. In reducing atmospheres, AUC undergoes thermal decomposition accompanied by reduction reactions, producing highly reactive UO. In engineered denitration processes, fluidized bed technology offers advantages in high-purity products with uniform particle size but faces challenges in equipment complexity and energy consumption. Flame denitration, through high-temperature transient reactions, generates UO3 with an ultrahigh specific surface area (up to 18.89 m2/g), demonstrating significant technological competitiveness. Furthermore, this review explores optimization strategies for reactor design under multiphysics coupling and proposes that the synergistic application of numerical simulations and thermal analysis techniques will establish a novel paradigm for mechanistic studies and process intensification.
JIANG Zhe,WANG Yi,XIN Cuncun et al. Nuclear Chemical Engineering Techniques for Thermochemical Reactions: Uranyl Nitrate Pyrolysis Process[J]. Chemical Reaction Engineering and Technology, 2025, 41(2): 333-344.
