Application of compressed air agitation in preparation of ADUN solution

The application of compressed air agitation in the mass production of acid-depleted of uranyl nitrate (ADUN) solution was studied using the acid-deficient dissolution method. The results show that the compressed air-agitation is suitable for the mass preparation of ADUN solution. The uranium dissolution rate is up to 99% at air compressed of 0.3 MPa, and the air flow rate of 200-300 L/h. The compressed air provides sufficient oxygen to inhibit the formation of nitrite. The NO₂^- concentration in the prepared ADUN solution is less than 1 g/L, and the cooking step can be omitted in subsequent use. 394 batches of acid-depleted solution of uranyl nitrate have been prepared by using compressed air agitation. The results showed that uranium concentration was between 556-623 g/L and the [NO₃^-]/[U] molar ratio between 1.56-1.75, both meeting the requirements of the preparation of UO₂ micro spheres by sol-gel method. (authors)