Thermodynamic Modeling of the SRS Evaporators: Part II. The 3H System

Jantzen, Carol M.; Laurinat, James E.

doi:10.2172/787457

Cited by 7 publications

(5 citation statements)

References 23 publications

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“…These phenomena occur in the Bayer aluminum process, [63][64][65] evaporators used in the wood pulp industry, 66 and evaporators used for radioactive waste management at the Savannah River Site. [67][68][69][70][71] Whether the Na-Al-Si gels (NAS gel ) form from solution via a hydrogel process or whether they form from a sol (solid particles in liquid) 72 via a sol-gel process, the aging sequence of the NAS gel to denser phases proceeds as NAS gel ?Zeolite-A?sodalite? cancrinite.…”

Section: Appendix 1 Tutorial On Zeolitization In Industrial Applicatimentioning

confidence: 99%

Accelerated Leach Testing of Glass (ALTGLASS): II. Mineralization of hydrogels by leachate strong bases

Jantzen

Trivelpiece

Crawford

et al. 2017

Int J of Appl Glass Sci

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The durability of high level nuclear waste glasses must be predicted on geological time scales. Waste glass surfaces form hydrogels when in contact with water for varying test durations. As the glass hydrogels age, some exhibit an undesirable resumption of dissolution at long times while others exhibit near steady‐state dissolution, that is, nonresumption of dissolution. Resumption of dissolution is associated with the formation of zeolitic phases while nonresumption of dissolution is associated with the formation of clay minerals. Hydrogels with a stoichiometry close to that of imogolite, (Al2O3·Si(OH)4), with ferrihydrite (Fe2O3·0.5H2O), have been shown to be associated with waste glasses that resume dissolution. Aluminosilicate hydrogels with a stoichiometry of allophane‐hisingerite ((Al,Fe)2O3·1.3‐2Si(OH)4) have been shown to be associated with waste glasses that exhibit near steady‐state dissolution at long times. These phases are all amorphous and poorly crystalline and are also found on natural weathered basalt glasses. Interaction of these hydrogels with excess alkali and OH− (strong base) in the leachates, causes the Al2O3·nSiO2 (where n=1‐2) hydrogels to mineralize to zeolites. Excess alkali in the leachate is generated by alkali in the glass. Preliminary rate‐determining leach layer forming exchange reactions are hypothesized based on these findings.

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Section: Appendix 1 Tutorial On Zeolitization In Industrial Applicatimentioning

confidence: 99%

Accelerated Leach Testing of Glass (ALTGLASS): II. Mineralization of hydrogels by leachate strong bases

Jantzen

Trivelpiece

Crawford

et al. 2017

Int J of Appl Glass Sci

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“…It should be noted that while these experiments confirm GWB calculations, they are not directly applicable to the SRS evaporator model as presented by Jantzen et al (2002aJantzen et al ( , 2002bJantzen et al ( , 2003aJantzen et al ( , 2003b …”

Section: Evaporation Experimentsmentioning

confidence: 61%

“…A thermodynamic model has been proposed to predict solids formation in the SRS evaporators from feed compositions (Jantzen et al, 2002a(Jantzen et al, , 2002b(Jantzen et al, , 2003a(Jantzen et al, , 2003b. In support of this work, researchers at Pacific Northwest National Laboratory (PNNL) and Oak Ridge National Laboratory (ORNL) have done experiments to evaluate solids formation under evaporator-like conditions in the laboratory.…”

Section: Executive Summarymentioning

confidence: 99%

Thermodynamic Modeling of the SRS Evaporators: Part V. Validation

Pareizs¹

2003

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“…A significant effort was expended to thermodynamically model the operation of the Site's High-Level Waste Evaporators. 14,15 In this work, a commercially available computer software called Geochemist's Workbench was used. This software package is capable of performing a number of equilibrium thermodynamic calculations simultaneously.…”

Section: Task 3: Thermodynamic Modeling To Predict Solution Behaviormentioning

confidence: 99%

Fate of Uranium during Sodium Aluminosilicate Formation under Waste Tank Conditions

Wilmarth¹

2005

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Experiments have been conducted to examine the fate of uranium during the formation of sodium aluminosilicate (NAS) when wastes containing high aluminate concentrations are mixed with wastes of high silicate concentration. Testing was conducted at varying degrees of uranium saturation. Testing examined typical tank conditions, e.g., stagnant, slightly elevated temperature (50 °C). The results showed that under sub-saturated conditions uranium is not removed from solution to any large extent in both simulant testing and actual tank waste testing. There are data supporting a small removal due to sorption of uranium on sites in the NAS. Above the solubility limit the data are clear that a reduction in uranium concentration occurs with the formation of aluminosilicate. This uranium precipitation is fairly rapid and ceases when uranium reaches its solubility limit. At the solubility limit, it appears that uranium is not affected, but further testing might be warranted. Lastly, analysis of the uranium speciation in a Tank 49H set of samples showed the uranium to be soluble. Analysis of the solution composition and subsequent use of the Hobb's uranium solubility model indicated a uranium solubility limit of 32 mg/L. The measured value of uranium in the Tank 49H matched the model prediction.

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Thermodynamic Modeling of the SRS Evaporators: Part II. The 3H System

Cited by 7 publications

References 23 publications

Accelerated Leach Testing of Glass (ALTGLASS): II. Mineralization of hydrogels by leachate strong bases

Accelerated Leach Testing of Glass (ALTGLASS): II. Mineralization of hydrogels by leachate strong bases

Thermodynamic Modeling of the SRS Evaporators: Part V. Validation

Fate of Uranium during Sodium Aluminosilicate Formation under Waste Tank Conditions

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