Kinetics of growth of spinel crystals in a borosilicate glass

Alton, Jesse; Plaisted, Trevor J.; Hrma, Pavel R.

doi:10.1016/s0009-2509(02)00121-5

Cited by 23 publications

(16 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As discussed in [3], cR max R can be interpreted as the hypothetical total (crystalline plus dissolved) spinel in glass. Eq.…”

Section: Theorymentioning

confidence: 99%

“…The presence of solid particles in glass is an issue of concern for commercial glass makers [1] as well as for high-level waste (HLW) vitrification [2,3,4,5,6]. Solid particles, also called stones, whether incompletely dissolved raw materials or precipitated crystals, are unacceptable in commercial glass products.…”

Section: Introductionmentioning

confidence: 99%

“…The growth and dissolution of spinel crystals in molten glass has been addressed in several papers. Alton et al [3] showed that the Hixson-Crowell equation better describes spinel growth and dissolution in a HLW glass melter than the Kolmogorov-Johnson-MehlAvrami equation. Izak et al [16] presented experimental observations of spinel response to the melt temperature history and the addition of noble metals that are effective nucleation agents.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Kinetic model for quartz and spinel dissolution during melting of high-level-waste glass batch

Pokorný

Rice

Crum

et al. 2013

Journal of Nuclear Materials

View full text Add to dashboard Cite

The dissolution of quartz particles and the growth and dissolution of crystalline phases during the conversion of batch to glass potentially affects both the glass melting process and product quality.Crystals of spinel exiting the cold cap to molten glass below can be troublesome during the vitrification of iron-containing high-level wastes. To estimate the distribution of quartz and spinel fractions within the cold cap, we used kinetic models that relate fractions of these phases to temperature and heating rate. Fitting the model equations to data showed that the heating rate, apart from affecting quartz and spinel behavior directly, also affects them indirectly via concurrent processes, such as the formation and motion of bubbles. Because of these indirect effects, it was necessary to allow one kinetic parameter (the pre-exponential factor) to vary with the heating rate. The resulting kinetic equations are sufficiently simple for the detailed modeling of batch-to-glass conversion as it occurs in glass melters. The estimated fractions and sizes of quartz and spinel particles as they leave the cold cap, determined in this study, will provide the source terms needed for modeling the behavior of these solid particles within the flow of molten glass in the melter.

show abstract

“…As discussed in [3], cR max R can be interpreted as the hypothetical total (crystalline plus dissolved) spinel in glass. Eq.…”

Section: Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Kinetic model for quartz and spinel dissolution during melting of high-level-waste glass batch

Pokorný

Rice

Crum

et al. 2013

Journal of Nuclear Materials

View full text Add to dashboard Cite

show abstract

“…Using a boundary-layer approach, Levich [6] obtained an analytical solution for a particle moving by buoyancy. The dissolution of multiple particles was described for stirred liquids [7,8] and later adapted to the case of sand grains in molten glass when the silica concentration in the melt was close to the solubility limit [9].…”

Section: Introductionmentioning

confidence: 99%

Dissolution retardation of solid silica during glass-batch melting

Hrma

Marcial

2011

Journal of Non-Crystalline Solids

View full text Add to dashboard Cite

During glass-batch melting, solid silica (quartz) usually dissolves last. The measured rate of dissolution, while the temperature was increasing at a constant rate, was compared with the hypothetical diffusion-controlled volume flux from regularly distributed particles through concentration layers of a uniform thickness. The actual rate was up to two orders of magnitude lower than that of the "ideal" case, revealing a progressive inhibition of silica dissolution. As a measure of this retarded dissolution, we introduced a retardation factor defined as a ratio of the actual and "ideal" dissolution rates measured as the volume flux at the melt-particle interface. The severe inhibition of silica dissolution has been attributed to the irregular spatial distribution of silica particles that is associated with the formation of nearly saturated melt on a portion of their surfaces. Irregular shapes and unequal sizes of particles also contribute to their extended lifetime.

show abstract

“…They also indicated that some submicron spinel from coldcap (feed pile) can be passed into the melt and provide nucleation sites for crystallization of spinel in the molten glass. Alton et al (2002b) followed with a statement that the noble metals (Rh, Ru, Pd, and Pt) increased n s independently of temperature by up to four orders of magnitude compared with MS-7 baseline glass.…”

Section: Introductionmentioning

confidence: 99%

HLW Glass Studies: Development of Crystal-Tolerant HLW Glasses

Matyáš¹,

Huckleberry²,

Rodriguez³

et al. 2012

View full text Add to dashboard Cite

iii SummaryTen glasses were prepared from high-level waste (HLW) AZ-101 simulant and additives. Eight of them were evaluated with a double crucible test for the effect of Cr, Ni, Fe, Al, Li, and RuO 2 on the accumulation rate of spinel crystals in the glass discharge riser of the HLW melter. The thicknesses of accumulated layers were incorporated into previously developed model of spinel settling (Matyáš et al. 2010a). In addition, the liquidus temperature (T L ) of glasses was measured and their crystallinity in mass % of spinel determined for heat-treatments at various temperatures for 24 h. The remaining two glass compositions enriched with Rh 2 O 3 and RuO 2 were investigated with scanning electron microscopy (SEM) and x-ray tomography for agglomeration of particles and impact of agglomerates on accumulation rate.The experimental study of spinel accumulation indicated that high concentrations of spinel-forming constituents in the glass can produce settling layers of a few cm thick in a few weeks. An excessive agglomeration of spinel in high-Ni-Fe glass (Ni1.5/Fe17.5) with agglomerates bigger than 500 µm resulted in the accumulation rate ~53.8 µm/h, which will produce ~2.6 cm thick layer in just 20 days of melter idling and can potentially plug the riser. Can noble metals decrease significantly this accumulation rate? There is an indication that they can. Additions of RuO 2 (in the form of ruthenium nitrosyl nitrate) to high-Ni glass (Ni1.5) effectively slowed down or stopped the spinel accumulation because of their effect on decreasing the average crystal size below 10 µm. Can the accumulation of thick but noncompacted spinel layer prevent the plugging of the riser? Maybe it can. Then, the additions of Al 2 O 3 and Li 2 O to glasses containing high concentration of spinel constituents might be the way. These components slowed down the growth of individual crystals but promoted the formation of a dendritic network of large needle-like spinel structures, which resulted in the non-compacted layers. There is a reasonable chance that spinel crystals locked in this configuration can be removed with glass during the pouring into canister.The previously developed model (Matyáš et al. 2010a) predicts well, R 2 = 0.981, the accumulation of crystals in the glasses with no or small-scale agglomeration, in which spinel settles as individual crystals and/or as clusters of a few crystals. But, in the case of excessive agglomeration, observed in the Ni1.5/Fe17.5 glass, the model under predicts the thicknesses of deposited layers. This under prediction was getting gradually worse with time as an increased number of larger agglomerates formed. Another factor that was not depicted by the model and that affected greatly the accumulation of spinel was the formation of 3D network of spinel needle-like structures in the Ni1.5/Al10 and Ni1.5/Li.38 glasses, which prevented a formation of a dense settled layer.The T L 's of tested glasses as determined with optical microscopy was between 950 to 1105°C. We have also measured the mass ...

show abstract

Kinetics of growth of spinel crystals in a borosilicate glass

Cited by 23 publications

References 9 publications

Kinetic model for quartz and spinel dissolution during melting of high-level-waste glass batch

Kinetic model for quartz and spinel dissolution during melting of high-level-waste glass batch

Dissolution retardation of solid silica during glass-batch melting

HLW Glass Studies: Development of Crystal-Tolerant HLW Glasses

Contact Info

Product

Resources

About