URANOUS NITRATE PREPARATION BY CATALYTIC REDUCTION: A PILOT PLANT FACILITY

摘要

A nonelectrolytic method for uranous preparation, deploying catalytic reduction with hydrogen leading to highly improved kinetics and near total conversion of uranyl nitrate to uranous nitrate, has been developed. Detailed experimental studies up to 5-ℓ scale, involving selection of stable supports for the platinum-based catalyst, optimized process parameters with regard to catalyst-to-uranium (C/U) ratio, acidity, hydrazine concentration, temperature, and pressure, have led to a deployable flow sheet, for near total conversion of uranyl nitrate to uranous nitrate. Based on the studies at various stages, a facility for making 70 ℓ of uranous per batch in 0.5-h duration has been installed, and the process has been demonstrated on a pilot scale. Active runs have been taken, with various C/U ratios, namely, 1:200, 1:250, 1:300, and 1:350, in a gas induction reactor with uranyl nitrate solution generated from the reprocessing plant.