ABSTRACTPreparation and characterization of inductively-melted Synroc containing 20
wt% simulated plant “Mayak” reprocessing waste were performed. The sample
bulk composition was as follows, (in wt.%): 55.4 TiO2; 15.8
ZrO2; 7.5 CaO; 7.4 BaO; 4.3 Al2O3 2.0
MnO; 1.8 SiO2; 0.7 Na2O; 1.9 K2O, 0.5
Ce2O3; 1.0 UO2; 0.9 NiO; 0.6
Cr2O3, and 0.2 FeO. The sample was produced by
melting in air at 1550–1600 °C under barometric pressure. It is composed of
a few crystalline phases and a minor glass phase. Most of the phases
(hollandite, zirconolite, perovskite and rutile) are similar to the
analogous phases found in the other Synroc formulations. An additional phase
with average composition, wt.%: 59.8 TiO2; 15.6 CaO; 7.0
UO2; 5.6 ZrO2; 4.7 MnO; 4.1
Ce2O3, and 1.8 Al2O3 was
found. Some elements (Ba, Si, Ni, K, Na, Fe) were present in the phase in
negligible quantities. Its formula
(Ca2.65U0.3Ce0.2)(Ti7.3Mn0.6Zr0.4Al0.3)O20.0
is rather close to a rare mineral uhligite -
Ca3(Ti,Zr,Al)9O20. Another possible
counterpart of the phase is murataite-like mineral previously described in
tailored ceramic designed for Savannah River Plant wastes fixation. This
phase as well as zirconolite are the major host for U in the sample
Preliminary data on the material leachability in water at 350 °C and 50 MPa
have been obtained Uranium contents in the solution were about 1 ppb and
close to the uranium dioxide solubility in deionized water under the same
P-T conditions.
PHYSICAL CHARACTERIZATION OF VITREOUS STATE LABORATORY AY102/C106 AND AZ102 HIGH LEVEL WASTE MELTER FEED SIMULANTS (U)
