高品位铀废渣处理工艺试验研究

针对铀燃料元件加工过程中产生的高铀含量放射性废渣(铀品位59.63%), 采用循环溶解、硝酸浸出、浓酸熟化、高温焙烧等工艺回收其中的铀。试验结果表明, 使用1∶1.2的稀硝酸溶液, 80 ℃水浴, 搅拌溶解4 h, 经过16次循环溶解, 得到铀含量为0.181%的不溶渣, 不溶残渣率为1.33%; 对于较难溶解的不溶渣, 通过工艺条件优选, 采用两级硝酸浸出, 渣中铀含量可降至0.059%。多次循环溶解和两级硝酸浸出工艺相结合, 可达到较好的回收效果。本研究结果为高品位铀废渣中铀的回收提供了试验依据。

Experimental Study on Treatment of High Grade Uranium Slag

Aiming at the radioactive waste residue with a high uranium content (with uranium grade at 59.63%) produced in the processing of uranium fuel elements, an experimental study was conducted for recovering uranium by process consisting of cyclic dissolution, nitric acid leaching, aging with concentrated acid and high temperature roasting. It is shown from the experiment that after 16 dissolution cycles with dilute nitric acid solution prepared in a 1∶1.2 ratio, water bath at 80 ℃ and 4 h agitation, an insoluble slag was obtained with a uranium content of 0.181%, with an insoluble residue rate at 1.33%. Based on the technical optimization, a process combining cyclic dissolution and two-stage nitric acid leaching can lead to the uranium content in the slag reduced to 0.059%, indicating a better recovery effect. This research can provide experimental reference for the recovery of uranium from high grade uranium residue.