UCO核芯颗粒制备工艺探索研究

Exploration and Research on Preparation Technology of UCO Kernels

针对高燃料效率、长寿命和安全性良好的UCO微球的规模化使用需求,本文通过开展硝酸铀酰溶解工艺、分散凝胶工艺及焙烧工艺研究,确定采用纯外凝胶法制备UCO微球最佳工艺参数。研究结果表明:U 3O 8粉末加入量为1000 g时,溶解最佳参数为硝酸加入量425 mL、去离子水加入量850 mL,当硝酸铀酰体积为100 mL、尿素加入量为37.8 g时,增稠剂的最佳加入量为90~93 g,既可保证分散后微球具有一定的强度,不会在干燥过程产生裂纹缺陷,又可保证其较好的成球性及分散效果。当UCO微球制备过程中原料的U/C摩尔比为1:1~1:2,可制备出含10%~15%UC 2相的UCO微球样品,核芯形貌较为均匀,球形度较好,表面平整、无沾污及夹杂物。

In view of the large-scale use requirements of UCO kernels with high fuel efficiency,long life and good safety,the uranyl nitrate dissolution process,disperse gel process and roasting process were studied in the paper to determine the optimal process parameters for the preparation of UCO kernels by pure external gel method.The results show that when the dosage of U 3O 8 powder is 1000 g,the optimal dissolution parameters are 425 mL nitric acid and 850 mL deionized water.When the volume of uranyl nitrate is 100 mL and the dosage of urea is 37.8 g,the optimal dosage of thickener is 90-93 g,which can ensure that the microspheres have the certain strength after dispersion.It will not produce crack defects in the drying process,and can ensure its good pelletization and dispersion effect.When the U/C molar ratio of the raw material is 1:1-1:2,UCO kernels containing 10%-15%UC 2 phase can be prepared.The core morphology is relatively uniform,the sphericity is good,the surface is smooth,and there is no contamination and inclusion.