UO_(2)陶瓷微球制备工艺中凝胶的回收再利用研究

Study on Gel Recovery and Reuse in Preparation of UO_(2) Ceramic Microspheres

研究了温度、pH、贮存时间、Urea与U摩尔比等因素对溶胶稳定性的影响。结果表明,当贮存温度为0℃时,溶胶可以稳定贮存6 h,随着温度和贮存时间的提高,溶胶的黏度会逐渐增大;尿素对溶胶中金属离子具有保护作用,当Urea与U摩尔比大于1时,有助于制备出球形度好的陶瓷微球。为了探究溶胶固化的根本原因,通过对比实验验证了引起溶胶凝固的主要原因是铀酰离子发生了水解缩合反应。最后,设计开发了凝胶煅烧回收的技术路线,X射线衍射结果证明在800℃下煅烧后凝胶完全转化为U3O8粉末,通过化学滴定法测定铀含量为83.24%,可直接用于缺酸溶解制备缺酸硝酸铀酰溶液,接着通过配胶、分散、洗涤、老化、烧结过程制备出了尺寸均匀的陶瓷微球。

The effects of temperature,pH,storage time,urea/U molar ratio and other factors on the stability of sol solution were studied.When the storage temperature was 0℃,the sol solution could be stably stored for 6 h,with the viscosity of t he sol solution to gradually increase with increasing temperature and storage time.Urea has protective effect on metal ions in the sol.When the molar ratio of urea/U is larger than 1,it is helpful to prepare ceramic microspheres with high sphericality.I n order to explore the cause of sol solidification,comparative experiments were conducted,verifying that solidification of the sol solution is mainly attributed to the hydrolysis condensation reaction of uranyl ions.Finally,the technical route for calcination recovery of the solidified sol was developed.X-ray diffraction results proved that the solidification sol was completely converted into U_(3)O_(8) powder after calcination at 800℃,while the uranium content was determined by chemical titration to be 83.24%,which could be directly used for acid deficiency dissolution to prepare acid deficiency uranyl nitrate solution.Ceramic microspheres with uniform size were obtained by glue,dispersion,washing,aging and sintering.