IGCAR : Annual Report - Indira Gandhi Centre for Atomic Research

IGC
Annual Report 2007
during nuclear fuel cycle
operations. A new method has
been developed for treating
these tissue paper wastes using
RTIL and electrochemical
recovery of the valuables
present in it. The procedure
involves the dissolution of
tissue paper waste in 1 butyl 3-
methylimidazolium chloride.
The study indicated that
dissolution of 5 - 7 wt. % tissue
paper in bmimCl was complete
within 60 minutes at 373 K.
The time required for
dissolution increased with
increase of loading. The
limiting solubility of tissue
paper was 15 -17 wt.% at 373
K. Contaminants such as
uranium (VI) and Pd (II) present
as chloride/nitrate salts also
dissolve in bmimCl along with
tissue paper. However they can
be recovered by
electrodeposition. Electrolysis
of a solution of uranium (VI)
and palladium(II) loaded tissue
paper in bmimCl resulted in
deposition of uranium oxide
(UO 2 ) and metallic palladium
(see Fig.1b), respectively, which
were characterized by X-ray
diffraction and scanning
electron microscopy. The study
established the possibility of
dissolving tissue paper and
other cellulose based materials
containing soluble uranium (VI)
and Pd(II) compounds in
bmimCl, and their recovery
from the resultant solution.
Cellulose pulp was regenerated
by adding surplus water after
the recovery of valuables and
the ionic liquid, bmimCl, was
also regenerated for further use
by vacuum distillation of water.
These experiments confirmed
the attractive possibility of
developing processes for
recovering valuable elements
from tissue paper waste without
generating significant
quantities of secondary waste
Fig.1b SEM image of palladium
deposit obtained by electrolysis of
palladium chloride (100 mM) in 5
wt.% tissue paper-bmimCl-DMSO
solution for 2 hours on SS plate at -
1.0 V (vs. Pd quasi reference)
at 298 K.
IV.B.5. Development of a Novel Mixer-Settler with Rotated
Helical Coils as Mixer for Nuclear Solvent Extraction
For current designs of
radiochemical plants, solvent
extraction (SX) contactors with
no periodic maintenance are
the first choice. In addition, as
costs of specialty solvents for
nuclear extraction are quite
high, there is a demand of SX
operation at extreme flow ratios
of the two phases (aqueous and
organic). Recently a novel
mixer-settler was visualized and
Fig.1 A view of the experimental setup
Helical mixer
102 FUEL CYCLE