The uranium-loaded solvent from the separation column is stripped back into aqueous form by back-washing with dilute nitric acid in mixer-settler contactors. Further purification is achieved by repeated organic solvent extraction cycles using 20% TBP/OK in large-volume mixer-settler tanks.
Uranium finishing converts the purified uranyl nitrate solution into uranium trioxide (UO₃) powder:
Method 1 — Thermal de-nitration:
Method 2 — Ammonia precipitation followed by calcination (gives better purity):
The UO₃ powder is packed in stainless steel drums for return to the conversion plant.