scholarly journals Predicting primary crystalline phase and liquidus temperature above or below 1050{degrees}C as functions of glass composition

1996 ◽  
Author(s):  
P.E. Redgate ◽  
G.F. Piepel
1996 ◽  
Vol 465 ◽  
Author(s):  
M. Mika ◽  
M. J. Schweiger ◽  
J. D. Vienna ◽  
P. Hrma

ABSTRACTThe liquidus temperature (TL) often limits the loading of high-level waste in glass through the constraint that TL must be at least 100°C below the temperature at which the glass viscosity is 5 Pa-s. In this study, values of TL for spinel primary crystalline phase were measured as a function of glass composition. The test glasses were based on high-iron Hanford Site tank wastes. All studied glasses precipitated spinel (Ni,Fe,Mn)(Cr,Fe)2O4 as the primary crystalline phase. TL was increased by additions of Cr2O3, NiO, Al2O3, Fe2O3, MgO, and MnO; while Li2O, Na2O, B2O3, and SiO2 had a negative effect. Empirical mixture models were fitted to data.


MRS Advances ◽  
2016 ◽  
Vol 1 (63-64) ◽  
pp. 4221-4225
Author(s):  
S. Mohd Fadzil ◽  
P. Hrma

ABSTRACTThe liquidus temperature (TL) of rare earth (RE) was determined for alumino-borosilicate glasses for treating americium and curium that have been studied previously. Their work covers a wide range of glass composition with various crystalline phases as primary phase. Present work is aimed at understanding the effect of glass composition on TL for waste glasses designed for vitrifying RE oxides wastes. In a sufficiently narrow composition region, this effect can be represented by a first-order model fitted measured TL versus composition data. Test glasses were formulated by varying of component fractions one-at-a-time. The glasses contained SiO2, B2O3, and Al2O3 as glass formers and Nd2O3 with CeO2 as simulated RE waste. Twenty glasses were made to investigate crystallization as a function of temperature and glass composition. The primary crystalline phase was Ce-borosilicate (Ce3BSi2O10), secondary phases were Al-containing crystals (Al2O3 and Al10Si2O19), and crystalline CeO2. A first-order model was fitted to crystal fraction versus glass composition data. Generally, SiO2 and B2O3 tend to suppress crystallization, Al2O3 has little effect, and, as expected, RE components (Nd2O3 and CeO2) promote it. The correlation coefficient, R2, was 0.89 for the primary crystalline phase TL as a linear function of composition.


2018 ◽  
Vol 766 ◽  
pp. 145-150
Author(s):  
Napaporn Vaiborisut ◽  
Chanittha Chunwises ◽  
Dararat Boonbundit ◽  
Sirithan Jiemsirilers ◽  
Apirat Theerapapvisetpong

Basalt fiber has been used as a reinforced material in cement-based materials because it has higher mechanical strength and cheaper than common silicate based glass-fibers. However, silicate-based glass fibers have low alkali resistance especially in cement matrix composite. In this work, we studied the improvement of alkali resistance by addition of zirconium silicate (ZrSiO4) in original basalt glass composition. The batch of basalt glass with additional ZrSiO4 contents of 0.00, 2.50, 5.00, 7.50 and 10.00 wt% were melted at 1500 °C. The liquidus temperature (TL) is important in for the fiber glass manufacturing. It need to formulate glass composition which requires a lower melting temperature and is crystallization resistant. TL as a function of composition is usually determined experimentally. In this study, glassy phase was determined by X-ray Diffraction (XRD). The glass transition temperature (Tg), the crystallization temperature (Tc) and TL were analyzed by Differential Thermal Analysis (DTA). The results found that the addition of ZrSiO4 in a basalt glass batch increased Tg while Tc of each sample was closed to original basalt fiber. Moreover, the alkali resistance of these glasses increased with an increasing of ZrSiO4 content. However, excessive ZrSiO4 contents (7.50 and 10.00 wt%) resulted in crystallization of ZrO2 which separated from glassy phase.


1996 ◽  
Vol 465 ◽  
Author(s):  
J. V. Crum ◽  
M. J. Schweiger ◽  
P. Hrma ◽  
J. D. Vienna

ABSTRACTA study was conducted on glasses based on a simulated transuranic waste with high concentrations of ZrO2and Bi2O3 to determine the compositional dependence of primary crystalline phases and liquidus temperature (TL). Starting from a baseline composition, glasses were formulated by changing mass fractions of Al2O3, B2O3, Bi2O3, CeO2, Li2O, Na2O, P2O5, SiO2, and ZrO2, one at a time, while keeping the remaining components in the same relative proportions as in the baseline glass. Liquidus temperature was measured by heat treating glass samples for 24 h in a uniform temperature furnace. The primary crystalline phase in the baseline glass and the majority of the glasses was zircon (ZrSiO4). A change in the concentration of certain components (Al2O3, ZrO2, Li2O, B2O3 and SiO2) changed the primary phase to baddeleyite (ZrO2), while cerium oxide (CeO2) precipitated from glasses with more than 3 wt% CeO2. Zircon TL was strongly increased by Al2O3, Zrb2 and CeO2, and slightly by P2O5 and SiO2; decreased strongly by Li2O and Na2O and moderately by B2O3. A first-order model was constructed for TL as a function of composition for zircon primary crystalline phase glass.


1999 ◽  
Vol 560 ◽  
Author(s):  
M. Mennig ◽  
F. Groß ◽  
I. Lang ◽  
U. Sohling ◽  
H. Schmidt

ABSTRACTGe-Ga-S-glasses doped with 15000 mole-ppm Pr3+ have been developed for applications in optical amplifiers for 1.3 μm. The formation of crystalline phase separations in Ge 25 Ga10 S65could be suppressed by modification of the glass composition with Sb. Samples have been prepared by melting in sealed silica ampoules at 950°C. Ge-Ga-Sb-S-glasses, doped with 15000 mole ppm Pr3+, were synthesized by addition of Sb2S3up to contents of 14.3 mole% to the composition Ge25,Ga10S65. (corresponding to 83,3GeS2-16,7Ga2S3) or by replacing up to 50 mole% of Ga by Sb. Transparent to opaque glasses were obtained which were free from crystalline phase separations. The modification of the glasses with Sb leads to a remarkable decrease of the transformation temperature of the glasses. However, the temperature working range remains almost unaffected. The transparent glasses exhibit with 15 – 18 μs the same fluorescence lifetimes and the same fluorescence maximum position (1340– 1341 nm) and FWHM (63 μm) as the unmodified Ge-Ga-S-glass. The preparation process for both glass systems could be optimized to obtain monoliths with lengths of several centimeters and intrin- sic optical losses of only 0.05 dB/cm at 1.3 μm (after correction of reflection), which is of very high importance for the future development of planar amplifiers with remarkable net gain.


2014 ◽  
Vol 384 ◽  
pp. 32-40 ◽  
Author(s):  
Pavel Hrma ◽  
Brian J. Riley ◽  
Jarrod V. Crum ◽  
Josef Matyas

Author(s):  
M. A. McCoy

Transformation toughening by ZrO2 inclusions in various ceramic matrices has led to improved mechanical properties in these materials. Although the processing of these materials usually involves standard ceramic powder processing techniques, an alternate method of producing ZrO2 particles involves the devtrification of a ZrO2-containing glass. In this study the effects of glass composition (ZrO2 concentration) and heat treatment on the morphology of the crystallization products in a MgO•Al2•SiO2•ZrO2 glass was investigated.


Author(s):  
N. S. Aryaeva ◽  
E. V. Koptev-Dvornikov ◽  
D. A. Bychkov

A system of equations of thermobarometer for magnetite-silicate melt equilibrium was obtained by method of multidimensional statistics of 93 experimental data of a magnetite solubility in basaltic melts. Equations reproduce experimental data in a wide range of basalt compositions, temperatures and pressures with small errors. Verification of thermobarometers showed the maximum error in liquidus temperature reproducing does not exceed ±7 °C. The level of cumulative magnetite appearance in the vertical structure of Tsypringa, Kivakka, Burakovsky intrusions predicted with errors from ±10 to ±50 m.


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