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Title: Impact Of Sodium Oxalate, Sodium Aluminosilicate, and Gibbsite/Boehmite on ARP Filter Performance

Abstract

The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. SRR requested SRNL to conduct bench-scale filter tests to evaluate whether sodium oxalate, sodium aluminosilicate, or aluminum solids (i.e., gibbsite and boehmite) could be the cause of excessive fouling of the crossflow or secondary filter at ARP. The authors conducted the tests by preparing slurries containing 6.6 M sodium Salt Batch 6 supernate, 2.5 g MST/L slurry, and varying concentrations of sodium oxalate, sodium aluminosilicate, and aluminum solids, processing the slurry through a bench-scale filter unit that contains a crossflow primary filter and a dead-end secondary filter, and measuring filter flux and transmembrane pressure as a function of time. Among the conclusions drwn from this work are the following: (1) All of the testsmore » showed some evidence of fouling the secondary filter. This fouling could be from fine particles passing through the crossflow filter. (2) The sodium oxalate-containing feeds behaved differently from the sodium aluminosilicate- and gibbsite/boehmite-containing feeds.« less

Authors:
 [1];  [1]
+ Show Author Affiliations
  1. Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
Publication Date:
Research Org.:
Savannah River Site (SRS), Aiken, SC (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1235439
Report Number(s):
SRNL-STI-2015-00465
TRN: US1600251
DOE Contract Number:
AC09-08SR22470
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; SODIUM COMPOUNDS; GIBBSITE; FILTERS; LIQUID WASTES; OXALATES; SOLVENT EXTRACTION; PERFORMANCE; RADIOACTIVE WASTE PROCESSING; REMOVAL; ALUMINIUM SILICATES; ACTINIDES; FOULING; SLURRIES; TIME DEPENDENCE

Citation Formats

Poirier, M., and Burket, P.. Impact Of Sodium Oxalate, Sodium Aluminosilicate, and Gibbsite/Boehmite on ARP Filter Performance. United States: N. p., 2015. Web. doi:10.2172/1235439.
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Poirier, M., & Burket, P.. Impact Of Sodium Oxalate, Sodium Aluminosilicate, and Gibbsite/Boehmite on ARP Filter Performance. United States. doi:10.2172/1235439.
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Poirier, M., and Burket, P.. Sun . "Impact Of Sodium Oxalate, Sodium Aluminosilicate, and Gibbsite/Boehmite on ARP Filter Performance". United States. doi:10.2172/1235439. https://www.osti.gov/servlets/purl/1235439.
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@article{osti_1235439,
title = {Impact Of Sodium Oxalate, Sodium Aluminosilicate, and Gibbsite/Boehmite on ARP Filter Performance},
author = {Poirier, M. and Burket, P.},
abstractNote = {The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. SRR requested SRNL to conduct bench-scale filter tests to evaluate whether sodium oxalate, sodium aluminosilicate, or aluminum solids (i.e., gibbsite and boehmite) could be the cause of excessive fouling of the crossflow or secondary filter at ARP. The authors conducted the tests by preparing slurries containing 6.6 M sodium Salt Batch 6 supernate, 2.5 g MST/L slurry, and varying concentrations of sodium oxalate, sodium aluminosilicate, and aluminum solids, processing the slurry through a bench-scale filter unit that contains a crossflow primary filter and a dead-end secondary filter, and measuring filter flux and transmembrane pressure as a function of time. Among the conclusions drwn from this work are the following: (1) All of the tests showed some evidence of fouling the secondary filter. This fouling could be from fine particles passing through the crossflow filter. (2) The sodium oxalate-containing feeds behaved differently from the sodium aluminosilicate- and gibbsite/boehmite-containing feeds.},
doi = {10.2172/1235439},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Nov 01 00:00:00 EDT 2015},
month = {Sun Nov 01 00:00:00 EDT 2015}
}
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Technical Report:
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DOI:  10.2172/1235439
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  • ;
    The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. One potential method for increasing filter flux is to adjust the axial velocity andmore » transmembrane pressure (TMP). SRR requested SRNL to conduct bench-scale filter tests to evaluate the effects of axial velocity and transmembrane pressure on crossflow filter flux. The objective of the testing was to determine whether increasing the axial velocity at the ARP could produce a significant increase in filter flux. The authors conducted the tests by preparing slurries containing 6.6 M sodium Salt Batch 6 supernate and 2.5 g MST/L, processing the slurry through a bench-scale crossflow filter unit at varying axial velocity and TMP, and measuring filter flux as a function of time.« less

  • ; ;
    The Savannah River National Laboratory (SRNL) was tasked with developing a test to determine the fraction of the gibbsite and boehmite forms of aluminum in the sludge solids. Knowledge of the fractions of gibbsite and boehmite in the sludge contained in various waste tanks would facilitate better sludge mass reduction estimates and allow better planning/scheduling for sludge batch preparation. The composite sludge sample prepared for use in the test from several small samples remaining from the original 3-L sample appears to be representative of the original sample based on the characterization data. A Gibbsite/Boehmite Test was developed that uses 8more » M NaOH and a temperature of 65 C to dissolve aluminum. The soluble aluminum concentration data collected during the test indicates that, for the three standards containing gibbsite, all of the gibbsite dissolved in approximately 2 hours. Under the test conditions boehmite dissolved at more than an order of magnitude more slowly than gibbsite. An estimate based on the soluble aluminum concentration from the sludge sample at two hours into the test indicates the sludge solids contain a form of aluminum that dissolves at a rate similar to the 100% Boehmite standard. Combined with the XRD data from the original 3-L sample, these results provide substantial evidence that the boehmite form of aluminum predominates in the sludge. A calculation from the results of the Gibbsite/Boehmite test indicates the sludge contains {approx}3% gibbsite and {approx}97% boehmite. The sludge waste in Tank 51H was recently treated under Low Temperature Aluminum Dissolution (LTAD) conditions and a substantial fraction of aluminum (i.e., sludge mass) was removed, avoiding production of over 100 glass canisters in Defense Waste Processing Facility (DWPF). Results of the Gibbsite/Boehmite test indicate that the aluminum in this sludge was in the form of the more difficult to dissolve boehmite form of aluminum. Since boehmite may be the dominant form of aluminum in Savannah River Site (SRS) waste tank sludge, this result suggests that the conditions of the LTAD process can be used to dissolve both the gibbsite and boehmite forms of aluminum in tank sludge and costly tank infrastructure upgrades required for the higher temperature baseline process can be avoided. However, this conclusion should be confirmed by testing additional waste tank samples.« less

  • ; ;
    A requirement for modelling the chemical behavior of groundwater in a nuclear waste repository is accurate thermodynamic data pertaining to the participating minerals and aqueous species. In particular, it is important that the thermodynamic properties of the aluminate ion be accurately determined, because most rock forming minerals in the earth's crust are aluminosilicates, and most groundwaters are neutral to slightly alkaline, where the aluminate ion is the predominant aluminum species in solution. Without a precise knowledge of the thermodynamic properties of the aluminate ion aluminosilicate mineral solubilities cannot be determined. The thermochemical properties of the aluminate ion have been determinedmore » from the solubilities of the aluminum hydroxides and oxyhydroxides in alkaline solutions between 20 and 350/degree/C. An internally consistent set of thermodynamic properties have been determined for gibbsite, boehmite, diaspore and corundum. The thermodynamic properties of bayerite have been provisionally estimated and a preliminary value for ..delta..G/sub f, 298//sup 0/ of nordstrandite has been determined. 205 refs., 17 figs., 25 tabs.« less

  • ; ;
    The Savannah River National Laboratory (SRNL) was requested to investigate the impact of decanting supernate from the Sludge Batch four (SB4) feed in Tank 40. The specific questions concerned the potential impact on the stoichiometric acid window determined for SB4 with respect to overall hydrogen generation rates, nitrite destruction in the Sludge Receipt and Adjustment Tank (SRAT) and the rheology of the sludge, SRAT product, and Slurry Mix Evaporator (SME) product slurries. The scope included considering an addition of sodium hydroxide to Tank 40 to partially offset the sodium lost during decanting as well as considering the impact of boundingmore » quantities of Actinide Removal Process (ARP) feed and Modular Caustic-Side Solvent Extraction Unit (MCU) feed on these same parameters. Simulated SB4 waste was first adjusted to match the dilution that has occurred in Tank 40 during the initial period of SB4 operations in the DWPF. The adjusted simulant was decanted an equivalent of 100,000 gallons relative to 413,740 gallons projected supernate volume. The decanted simulant was divided into two equal parts. One part received an addition of sodium hydroxide to increase the Na{sub 2}O content of the calcined sludge solids by about 3%. The baseline decanted simulant and caustic adjusted simulant were each tested in three pairs of DWPF process simulations of the SRAT and SME cycles. The simulations were at the nominal SB4 acid stoichiometry of 130% with and without bounding ARP/MCU additions and at 170% of acid without ARP/MCU. The 170% case without ARP/MCU was considered bounding relative to 170% with ARP/MCU based on calculated acid requirements. No significant negative impacts on the proposed acid operating window for the SRAT and SME cycles were noted in the simulations. Nitrite was successfully destroyed and mercury reduced in all six SRAT cycles. Hydrogen was produced in all six SRAT and SME cycles, but the levels were below the DWPF SRAT and SME cycle limits in all cases. Relatively insignificant rheological changes were noted other than the previously established thinning from higher acid additions. SRAT and SME processing at 130% acid stoichiometry with and without ARP/MCU additions were very similar. MCU nitric acid content, however, shifted the normal acid addition prior to boiling toward more formic acid and less nitric acid than without MCU. SRNL found no technical issues processing the proposed Tank 40 decant (with or without added NaOH) from the standpoint of the impact on the DWPF SRAT and SME cycles subject to the inherent uncertainties in modeling the ARP noble metal concentrations. The noble metals in the ARP were set to the same weight percents in the total solids that they were measured at in the SB4 waste, which was considered likely to be bounding on the actual noble metal content of the ARP transfer to DWPF. Assumptions for formate loss and nitrite to nitrate conversion can be left at the current levels.« less

  • ;
    The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. There is a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. This task attempted to simulate the entire ARP process, including multiple batches (5), washing, chemical cleaning, andmore » blending the feed with heels and recycle streams. The objective of the tests was to determine whether one of these processes is causing excessive fouling of the crossflow or secondary filter. The authors conducted the tests with feed solutions containing 6.6 M sodium Salt Batch 6 simulant supernate with no MST.« less