Unveiling dynamic mechanism of crystallization for the uranium peroxide

As a critical fuel of nuclear energy, uranium peroxide precipitation and conversion represent critical steps in uranium extraction processes, directly determining the purity and recovery efficiency of the final product. However, the dynamic mechanism of uranium peroxide precipitation and conversion remains unclear. Here, we investigated the crystallization kinetics of metal peroxides, establishing empirical equations between crystallization rate and solution supersaturation under different metal concentration ranges. Combining the experimental observations with theoretical calculations, we showed that at the lower metal concentration the crystal growth dominates the crystallization process, while at the higher concentration range nucleation becomes the dominant process. Further, mathematical models were developed to correlate crystallization rate with solution composition and operating parameters. Our findings provide fundamental insights to support the development of more efficient and scalable precipitation processes, addressing key challenges in uranium purification and recovery.