scholarly journals Effects of glass surface area-to-solution volume ratio (S/V) on glass dissolution. Part one: Relationship between S/V and leachate pH

1992 ◽  
Author(s):  
X. Feng ◽  
I.L. Pegg
Keyword(s):  
Surface Area ◽  
Glass Surface ◽  
Volume Ratio ◽  
Glass Dissolution ◽  
Solution Volume

Glass Surface area to Solution Volume Ratio and its Implications to Accelerated Leach Testing

1982 ◽  
Vol 15 ◽  
Author(s):  
Larry R. Pederson ◽  
Charles Q. Buckwalter ◽  
Gary L. Mcvay ◽  
B. Lynn Riddle
Keyword(s):  
Solid State ◽  
Surface Area ◽  
Glass Surface ◽  
Volume Ratio ◽  
Leaching Tests ◽  
Soluble Glass ◽  
State Diffusion ◽  
Dissolved Silicon ◽  
Glass Leaching ◽  
Solution Volume

ABSTRACTLeaching tests of PNL 76–68 glass in deionized water have been performed using the standard MCC-l static leaching procedure but with varied glass surface area to solution volume ratios (SA/V). It was found that leaching could be strongly influenced by the SA/V ratio, due largely to an effect of silicon solubility limitations. The conclusion that solubility and not solid state diffusion is most important in regulating leaching rates is supported by (1) the similarities in depth profiles of all soluble glass components with none depleted to depths greater than that of silicon despite vastly different solid state diffusivities, and (2) the lack of dependence of leaching rates on reaction layer thicknesses. To more directly examine the influence of dissolved silicon on glass leaching rates, leaching tests were performed in silicic acid solutions and in two actual groundwaters. As expected, leaching rates of all soluble glass components were reduced by amounts roughly proportional to the silicon saturation fraction. Since solubility modifies leaching rates in all but very dilute solutions, short-term tests at high SA/V values can be used to predict solution concentrations for long-term tests at low SA/V values, although reaction layers formed are not of the same thickness. Glass leaching data for a range of leaching times and SA/V values can be represented by a single curve when plotted versus the product of SA/V and time. However, the use of SA/V variations may have limited usefulness in accelerated leach testing for multicomponent systems. Events such as silica colloid and certain alteration phase formations modify the above relationship.

Complex Study of E-Glass Corrosion

2008 ◽  
Vol 39-40 ◽  
pp. 279-286 ◽  
Author(s):  
Pavel Šlemín ◽  
Gerhard Heide ◽  
Aleš Helebrant
Keyword(s):  
Glass Surface ◽  
Volume Ratio ◽  
Solution Flow Rate ◽  
Solution Flow ◽  
Glass Fibres ◽  
Glass Corrosion ◽  
Sample Shape ◽  
Congruent Dissolution ◽  
Different Shapes ◽  
Solution Volume

Both the static and dynamic corrosion tests of E-glass were used for different conditions - temperature, glass surface to solution volume ratio (S/V), solution flow rate (F) and F/S ratio. Results obtained for glass fibres were compared with the ones for glass grains and planar samples. Evaluation of experimental results by kinetic model shows that the change of glass surface should be taken into account in the case of fibres corrosion. The total incongruent process of dissolution could be explained as congruent dissolution of glass accompanied by back precipitation of SiO2 or silicates. In most cases, more then 90% of SiO2 precipitates back. The second possible explanation, i.e. SiO2 network dissolution accompanied by selective leaching of Ca, B and Al, is not very probable. The glass sample shape can influence the estimation of dissolution rate. Up to now, with existing kinetic models, the dissolution rates evaluated from experiments with different shapes of glass (fibres, grains, planar) cannot be used as materials properties.

Uranium Sorption on α-Alumina: Effects of pH and Surface-Area/Solution-Volume Ratio

1994 ◽  
Vol 66-67 (s1) ◽  
Author(s):  
James D. Prikryl ◽  
Roberto T. Pabalan ◽  
David R. Turner ◽  
Bret W. Leslie
Keyword(s):  
Surface Area ◽  
Volume Ratio ◽  
Effects Of Ph ◽  
Solution Volume

scholarly journals The Release of Technetium from Defense Waste Processing Facility Glasses

1995 ◽  
Vol 412 ◽  
Author(s):  
W. L. Ebert ◽  
S. F. Wolf ◽  
J. K. Bates
Keyword(s):  
Glass Surface ◽  
Laboratory Tests ◽  
Water Solution ◽  
Waste Processing ◽  
Glass Dissolution ◽  
Test Conditions ◽  
Processing Facility ◽  
Nitrite Nitrate ◽  
Solution Volume

AbstractLaboratory tests are being conducted using two radionuclide-doped Defense Waste Processing Facility (DWPF) glasses (referred to as SRL 131A and SRL 202A) to characterize the effects of the glass surface area/solution volume (SN) ratio on the release and disposition of Tc and several actinide elements. Tests are being conducted at 90°C in a tuff ground water solution at S/V ratios of 10, 2000, and 20,000 m−1 and have been completed through 1822 days. The formation of certain alteration phases in tests at 2000 and 20,000 m−1 results in an increase in the dissolution rates of both glasses. The release of Tc parallels that of B and Na under most test conditions and its release increases when alteration phases form. However, in tests with SRL 202A glass at 20,000 m−1, the Tc concentration in solution decreases coincidentally with an increase in the nitrite/nitrate ratio that indicates a decrease in the solution Eh. This may have occurred due to radiolysis, glass dissolution, the formation of alteration phases, or vessel interactions. Technetium that was reduced from Tc(VII) to Tc(IV) may have precipitated, though the amount of Tc was too low to detect any Tc-bearing phases. These results show the importance of conducting long-term tests with radioactive glasses to characterize the behavior of radionuclides, rather than relying on the observed behavior of nonradioactive surrogates.

Effects of Surface Area-to-Solution Volume Ratio on Chemical Durability of Nuclear Waste Glasses

1989 ◽  
Vol 176 ◽  
Author(s):  
X. Feng ◽  
I. L. Pegg ◽  
Y. Guo ◽  
AA. Barkatt ◽  
P. B. Macedo
Keyword(s):  
Surface Area ◽  
Nuclear Waste ◽  
Volume Ratio ◽  
Fixed Time ◽  
Waste Glass ◽  
Corrosion Mechanism ◽  
General Tendency ◽  
Savannah River ◽  
Report Data ◽  
Solution Volume

ABSTRACTWe report data on the relationship between nuclear waste glass durability, as measured by leachate concentrations and leach rates, and the ratio of glass surface area to solution volume, S/V. The study includes West Valley non-radioactive production glasses (SF6 and SF10), West Valley glasses containing U and Th designed at CUA (WVCM47, WVCM50, and WVCM59), Savannah River SRLTDS-131 glass, and Hanford waste glass HW-39 (for which existing literature data is used). While some of these glasses show departures of leachate concentrations from simple (S/V)t scaling others conform well. The departures are, in all cases, most evident at high values of S/V. It is therefore important, therefore to understand how glass composition determines which corrosion mechanism is dominant in order to assess the region of validity of extrapolations based on (S/V)t scaling. While leach rates show a general tendency to decrease with S/V and time, exceptions are evident for the less durable glasses which show minima and maxima in the S/V-dependence at fixed time.

Monte Carlo Modelling of Glass Dissolution: Comparison with Experiments

2000 ◽  
Vol 663 ◽  
Author(s):  
M. Lobanova ◽  
L. Maurer ◽  
P. Barboux ◽  
F. Devreux ◽  
Y. Minet
Keyword(s):  
Surface Layer ◽  
Volume Ratio ◽  
Protective Role ◽  
Glass Dissolution ◽  
Altered Surface ◽  
Alkali Oxides ◽  
Soluble Species ◽  
Glass Leaching ◽  
Solution Volume

ABSTRACTOne presents the results of numerical simulations of glass leaching. The glass is modelled as a random mixture of partly and totally soluble species, which represent silica, and boron or alkali oxides, respectively. It is shown that the dissolution rate and the thickness of the altered surface layer are strongly dependent on the glass composition, whereas the equilibrium solubility is not. The dependence of the layer thickness on the glass surface area to solution volume ratio is also emphasized. The protective role of the surface layer is shown to arise from its restructuring after the extraction of the soluble species. The simulation results are compared to an experimental study performed on series of SiO2-B2O3-Na2O glasses.

Colloid Formation During the Interaction of HLW Glass with Interstitial Clay Water

1996 ◽  
Vol 465 ◽  
Author(s):  
J. Wei ◽  
P. Van Iseghem
Keyword(s):  
Size Distribution ◽  
Surface Area ◽  
Glass Surface ◽  
Waste Glass ◽  
Complexation Reaction ◽  
Different Temperatures ◽  
Colloid Formation ◽  
Solution Volume

ABSTRACTDuring the reaction of HLW glass with interstitial clay water at different temperatures with various ratios of glass surface area to solution volume (SA/V) and durations, Eu released from the glass forms predominantly Eu-humate colloids (organic colloids) by a complexation reaction. The size distribution and stability of Eu-humate colloids have been characterized. It is likely that inorganic colloids which are mainly composed of Si, Al and Ca are generated from the corrosion of waste glass by a nucleation reaction.

scholarly journals Modeling Surface Area to Volume Effects on Borosilicate Glass Dissolution

1992 ◽  
Vol 294 ◽  
Author(s):  
William L. Bourcier ◽  
W. L. Ebert ◽  
X. Feng
Keyword(s):  
Ion Exchange ◽  
Surface Area ◽  
Ph Effect ◽  
Volume Ratio ◽  
Solution Ph ◽  
Exchange Effect ◽  
Dissolution Experiment ◽  
Glass Dissolution ◽  
Time Value ◽  
Long Time

ABSTRACTWe simulated the reaction of SRL-131 glass with equilibrated J-13 water in order to investigate the effects of surface area to volume ratio (SAN/) on glass dissolution. We show that glass-fluid ion exchange causes solution pH to rise to progressively higher values as SA/V increases. Because the ion exchange is rapid relative to the duration of the glass dissolution experiment, the pH effect does not scale with (SA/V)*time. Experiments compared at the same (SA/V)*time value therefore have different pHs, with higher pHs at higher SA/V ratios. Both experimental data and our simulation results show similar trends of increasing reaction rate as a function of SAN ratio when scaled to (SA/V)*time. Glasses which react in systems of differing SA/V ratio therefore follow different reaction paths and high SAN ratios cannot be used to generate data which accurately scales to long time periods unless the ion exchange effect is taken into account. We suggest some simple test designs which enable more reliable high SAN accelerated tests.

Uranium Sorption on α-Alumina: Effects of pH and Surface-Area/Solution-Volume Ratio

1994 ◽  
Vol 66-67 (s1) ◽  
Author(s):  
James D. Prikryl ◽  
Roberto T. Pabalan ◽  
David R. Turner ◽  
Bret W. Leslie
Keyword(s):  
Surface Area ◽  
Volume Ratio ◽  
Effects Of Ph ◽  
Solution Volume
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