Treatment of alkaline waste containing uranium generated during preparation of UO3 microspheres by internal gelation process

Preparation of each Kg of UO3 microspheres by Internal Gelation Process produces approximately 15 Litres of alkaline waste containing hexamethylenetetramine (HMTA), urea, NH4OH, NH4NO3 besides traces of uranium (few mg per litre). Earlier studies carried out at FCD, BARC have shown that nitrate ion can be separated from the waste using Dowex 1 x 4 anion exchange resin and 1 M NaOH as eluant and HMTA and urea can be recycled. Present studies have shown that uranium present in the waste goes with the eluted fraction, along with NaOH and NaNO3, which resulted in same volume of secondary waste. Loading and elution behaviour of uranium have shown that uranium loads in preference to nitrate ion on the resin while elution of uranium is kinetically faster than nitrate ion. It has been estimated that by pre-treating the waste (prior to recycling process starting with nitrate ion separation) by passing through the anion exchange resin, uranium could be confined to a smaller volume. (author)