Hafnium in peralkaline and peraluminous boro-aluminosilicate glass, and glass subcomponents: a solubility study.

Journal Article · Wed Oct 15 00:00:00 EDT 2003 · Journal of Non-crystalline Solids

DOI:https://doi.org/10.1016/S0022-3093(03)00479-4· OSTI ID:15008751

Davis, Linda L; Darab, John G; Qian, Maoxu; Zhao, Donggao; Palenik, Christopher S; Li, Hong; Strachan, Denis M; Li, Liyu

A relationship between the solubility of hafnia (HfO2) and the host glass composition was explored by determining the solubility limits of HfO2 in peralkaline and peraluminous borosilicate glasses in the system SiO2-Al2O3-B2O3-Na2O, and in glasses in the system SiO2-Na2O-Al2O3 in air at 1450 C. The only Hf-bearing phase to crystallize in the peralkaline borosilicate melts is hafnia, while in the boron-free melts sodium-hafnium silicates crystallize. All peraluminous borosilicate melts crystallize hafnia, but the slightly peraluminous glasses also have sector-zoned hafnia crystals that contain Al and Si. The more peraluminous borosilicate glasses also crystallize a B-containing mullite. The general morphology of the hafnia crystals changes as peralkalinity (Na2O/(Na2O+Al2O3)) decreases, as expected in melts with increasing viscosity. In all of the glasses with Na2O > Al2O3, the solubility of hafnia is linearly and positively correlated with Na2O/(Na2O + Al2O3) or Na2O - Al2O3 (excess sodium), despite the presence of 5 to 16 mol% B2O3. The solubility of hafnia is higher in the sodium-aluminum borosilicate glasses than in the sodium-aluminosilicate glasses, suggesting that the boron is enhancing the effect that excess sodium has on the incorporation of Hf into the glass structure. The results of this solubility study are compared to other studies of high-valence cation solubility in B-free silicate melts. From this, for peralkaline B-bearing glasses, it is shown that, although the solubility limits are higher, the solution behavior of hafnia is the same as in B-free silicate melts previously studied. By comparison, also, it is shown that in peraluminous melts, there must be a different solution mechanism for hafnia: different than for peralkaline sodium-aluminum borosilicate glasses and different than for B-free silicate melts studied by others.

• Research Organization: Pacific Northwest National Lab., Richland, WA (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 15008751
• Report Number(s): PNNL-SA-33318; KP1301020; TRN: US0403697
• Journal Information: Journal of Non-crystalline Solids, Vol. 328, Issue 1-3; Other Information: PBD: 15 Oct 2003
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
BOROSILICATE GLASS
HAFNIUM OXIDES
MORPHOLOGY
MULLITE
SOLUBILITY
VISCOSITY
ALUMINIUM OXIDES
BORON OXIDES
SILICON OXIDES
SODIUM OXIDES
PHASE STUDIES
PLUTONIUM
SIMULATION
HF(IV)SATURATION
WASTE GLASSES
PU SURROGATES