12 research outputs found
A âTwo-Stepâ Electrochemical Approach for Recovery of Plutonium and Uranium from Aqueous Acidic Waste Solutions
Chemical quality control of nuclear fuel, particularly
the determination
of Pu and U contents by chemical methods, results in analytical acidic
aqueous waste solutions from which Pu and U must be recovered efficiently
for the remediation of radioactive wastes. Reported methods involve
several complicated steps requiring addition of chemical oxidants/reductants
for valence adjustments and generation of secondary wastes, thereby
making the recovery process cumbersome. Herein, we report a novel
two-step electrochemical approach for Pu and U recovery from acidic
aqueous waste solutions containing different metallic impurities (Fe,
Cr, Mn, Cd, Al, Ni, Co, Zn, and Mg) by bulk electrolysis using a Pt
gauze electrode. Pu and U are recovered from these waste solutions
in a two-step process: (i) bulk electrolysis of the mixed solution
at a constant potential of 0.1 V vs Ag/AgCl/3 M KCl that results in the reduction of PuO22+ to
Pu3+ followed by the precipitation of Pu3+ as
K2(K0.5Pu0.5)(SO4)2, which is then filtered and separated and (ii) the filtrate
solution is again subjected to bulk electrolysis at a constant potential
of â0.35 V vs Ag/AgCl/3 M KCl resulting in
the reduction of UO22+ to U4+. The
U4+ is then precipitated as K2(K0.67U0.33)(SO4)2, which is filtered
and separated, leading to a Pu- and U-free aqueous acidic waste solutions.
Biamperometry shows that 97.8% and 99.1% recovery of Pu and U, respectively,
is possible, and emission spectrometry confirms the purity of K2(K0.5Pu0.5)(SO4)2 and K2(K0.67U0.33)(SO4)2. Because of its operational simplicity, potential for
remote handling, and excellent extraction efficiency, the present
methodology can easily replace traditional methods for the recovery
of Pu and U from acidic aqueous waste solutions