Surface Layer Formation on a Nuclear Waste Glass

1982 ◽  
Vol 15 ◽  
Author(s):  
Werner Lutze ◽  
GÜnter Malow ◽  
Harald Rabe ◽  
Thomas J. Headley
Keyword(s):  
Waste Glass ◽  
Layer Formation ◽  
Surface Layers ◽  
Protective Function ◽  
Leach Rate ◽  
Simulated Waste ◽  
Volcanic Glasses ◽  
The Stability ◽  
Kinetics Of ◽  
Surface Layer Formation

Surface layers are a common feature of leached surfaces of borosilicate waste glasses. Layers are also observed upon weathering of volcanic glasses[l] and of silicate minerals[2]. The question of whether these layers can protect the glass against further attack by decreasing the leach rate is stïll a subject of controversy[3]. Both in geochemical work[4] and in work on waste forms [5,6], surface layers are attributed a protective function, and the stability of leached, million years old volcanic glasses[1] may be due to the presence of palagonite, a thin (≤100 μm) alteration layer, which forms in a few years but does not seem to increase in thickness after this time. The present study investigates the effects of layer formation on leaching kinetics of a borosilicate waste glass containing 20 wt.% LWR-type simulated waste oxides.

Growth of Surface Layer During the Leaching of The Simulated Waste Glass and its Barrier Effects on the Leaching

1982 ◽  
Vol 15 ◽  
Author(s):  
K. Ishiguro ◽  
N. Kawanishi ◽  
N. Sasaki ◽  
H. Nagaki ◽  
M. Yamamoto
Keyword(s):  
Effective Diffusion ◽  
Waste Glass ◽  
Transition Elements ◽  
Surface Layers ◽  
Barrier Effects ◽  
Corrosion Kinetics ◽  
Layer Structures ◽  
Simulated Waste ◽  
Different Types ◽  
Kinetics Of

ABSTRACTThe growth of surface layers on simulated waste glass during two different types of leaching has been studied in conjunction with their corrosion kinetics. Static and Soxhlet leach tests were performed in distilled water at a temperature of 100°C. Auger and ESCA analyses of solid samples after leaching showed that the layers consisted of two or three sublayers which were distinguished by their different components. The transition elements Fe and Ni, the rare-earths Nd and La, and Zn were concentrated in the layers, while Si, B and alkali were depleted in most of the layers. Growth kinetics of the layers followed approximately linear relations for the two types of leaching. Growth rates and elemental profiles of the layers depended upon the leaching conditions. Comparison between the leaching rate and the thickness of the layer showed that layers did not work as effective diffusion barriers until a threshold thickness was reached, which depended on the layer structures.

scholarly journals Chemical Durability of Glass Containing Srp Waste - Leachability Characteristics, Protective Layer Formation, and Repository System Interactions

1981 ◽  
Vol 11 ◽  
Author(s):  
George G. Wicks ◽  
Barbara M. Robnett ◽  
W. Duncan Rankin
Keyword(s):  
Protective Layer ◽  
Layer Formation ◽  
Surface Layers ◽  
Waste Products ◽  
Safety And Reliability ◽  
Experimental Findings ◽  
Nuclear Waste Forms ◽  
Leaching Models ◽  
Surface Layer Formation

Leachability is one of the most important properties of solidified nuclear waste forms because it provides information on the performance and the subsequent safety and reliability that the waste products will possess. One of the most important experimental findings in the leachability field has been the discovery and subsequent detailed characterization of protective surface layers that form on waste glass during leaching. These layers can have a beneficial effect on product performance while in storage by improving productdurability with time. As a result of surface layer formation and the effects on subsequent product leaching characteristics, new qualitative and quantitative leaching models have recently been proposed.

Corrosion Resistance of Ceramic Refractories to Simulated Waste Glasses at High Temperatures

1995 ◽  
Vol 412 ◽  
Author(s):  
Shi-Ben Xing ◽  
Yijing Lin ◽  
Robert K. Mohr ◽  
Ian L. Pegg
Keyword(s):  
Compositional Analysis ◽  
Waste Glass ◽  
Refractory Materials ◽  
Minor Components ◽  
Simulated Waste ◽  
Refractory Life ◽  
Added Benefit ◽  
Higher Temperature ◽  
Test Increase ◽  
Kinetics Of

AbstractIn many vitrification processes, refractory materials are used to contain the waste glass melt. The corrosive nature of the high-temperature melt consumes the waste feed materials but also limits refractory life. As vitrification is applied to more diverse waste streams, and particularly in higher-temperature applications, increasingly severe demands are placed on the refractory materials. A variety of potential refractory materials including Fused-cast AZS, Monofrax K3, Monofrax E, and the Corhart refractories ER1195, ER2161, C1215, C1215Z, Rechrome, and TI 186, were subjected to corrosion testing at 1450°C using the ASTM C-621 procedure. A series of simulated waste glasses was used which included F, Cl, S, Cu, Zn, Pb; these minor components were found to cause significant, and in some cases drastic, increases in corrosion rates. The corrosion tests were conducted over a range of time intervals extending to 144 hrs in order to investigate the kinetics of the corrosion processes. The change of the concentrations of constituents in the glass was monitored by compositional analysis of glass samples and correlated to the observed extent of corrosion; typically, components of the material under test increase with time while key minor components, such as Cu and Pb, decrease. The rate of corrosion of high-zirconia refractories was slowed considerably by adding zirconia to the waste glass composition; this has the added benefit of improving the aqueous leach resistance of the waste form that is produced.

Characterization of Highly Waste Loaded Glass for HLW

1994 ◽  
Vol 353 ◽  
Author(s):  
Kazuhiro Kawamura ◽  
Jin Ohuchi
Keyword(s):  
Waste Glass ◽  
Apatite Crystal ◽  
Borosilicate Glasses ◽  
Good Thermal Stability ◽  
Leach Rate ◽  
Heat Treated ◽  
Simulated Waste ◽  
Temperature Transformation ◽  
Thermal Stability Of

AbstractPossibility of highly waste loaded borosilicate glasses up to 65wt% were investigated for HLW. In the case the waste was loaded at a content higher than 45wt%, apatite crystal was identified in the glasses. Adding above 2.5wt% of M0O3, yellow phase was observed in the 45wt% waste glass. In the case the composition of actual waste was simulated, waste(25–45wt%) glasses were characterized. Chemical durability of 45wt% waste glass was equivalent to that of 25wt% waste glass under the condition of Na20 content lower than 12wt%. Rheological behavior of 45wt% waste glass was equivalent to that of 25wt% waste glass in the range of melting temperature. Electrical resistivity of 45wt% waste glass were a little lower than that of 25wt% waste glass and it depended on the noble metal content. The Time-Temperature-Transformation (T-T-T) diagram and the leach rate of heat treated glass indicated a good thermal stability of highly waste loaded glass below the glass transition temperature. Possibility of high waste loading up to 45wt% was elucidated.

Poly(ether imide)/N -methyl pyrrolidinone solutions: kinetics of water vapour absorption and surface layer formation

2008 ◽  
Vol 57 (5) ◽  
pp. 778-784 ◽  
Author(s):  
Céline Pochat-Bohatier ◽  
Jean-Pierre Cohen-Addad ◽  
Watchanida Chinpa ◽  
André Deratani
Keyword(s):  
Surface Layer ◽  
Water Vapour ◽  
Layer Formation ◽  
Water Vapour Absorption ◽  
Kinetics Of ◽  
Surface Layer Formation

Durability of simulated waste glass - effects of pressure and formation of surface layers

1982 ◽  
Vol 49 (1-3) ◽  
pp. 413-428 ◽  
Author(s):  
George G Wicks ◽  
W.C Mosley ◽  
Peter G Whitkop ◽  
Kathy A Saturday
Keyword(s):  
Waste Glass ◽  
Surface Layers ◽  
Simulated Waste

Detailed Processes of Surface Layer Formation in Borosilicate Waste Glass Dissolution

1984 ◽  
Vol 44 ◽  
Author(s):  
John F. Flintoff ◽  
Alan B. Harker
Keyword(s):  
Chemical Structure ◽  
Development Process ◽  
Waste Glass ◽  
Surface Layers ◽  
Glass Dissolution ◽  
Surface Spectroscopy ◽  
Local Saturation ◽  
Saturation Effects ◽  
Layer Development ◽  
Surface Layer Formation

AbstractThe morphology and chemical structure of surface layers formed during the aqueous leaching of the SRP-type borosilicate waste glass in simulated ground waters have been studied by SEM/EDXS, XRD, and surface spectroscopy. Comparison of layers formed in deionized, silicate, and brine waters shows the processes of both corrosion and precipitation to be highly localized. The corrosion process proceeds on the glass surface preferentially at points of stress and inhomogeneity. Crystalline and noncrystalline precipitates form in well-defined regions within the surface layers indicating the layer development process to be dominated by species migration and local saturation effects.

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