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Title: Precipitation and Deposition of Aluminum-Containing Species in Tank Wastes

Abstract

Aluminum-containing phases represent the most prevalent solids that can appear or disappear during the processing of radioactive tank wastes. Processes such as sludge washing and leaching are designed to dissolve Al-containing phases and thereby minimize the volume of high-level waste glass required to encapsulate radioactive sludges. Unfortunately, waste-processing steps that include evaporation can involve solutions that are supersaturated with respect to cementitious aluminosilicates that result in unwanted precipitation and scale formation. Of all the constituents of tank waste, limited solubility cementitious aluminosilicates have the greatest potential for clogging pipes and transfer lines, fouling highly radioactive components such as ion exchangers, and completely shutting down processing operations. For instance, deposit buildup and clogged drain lines experienced during the tank waste volume-reduction process at the Savannah River Site (SRS) required an evaporator to be shut down in October 1999. The Waste Processing Technology Section of Westinghouse Savannah River Company at SRS now is collaborating with team members from Pacific Northwest National Laboratory (PNNL) to verify the thermodynamic stability of aluminosilicate compounds under waste tank conditions in an attempt to solve the deposition and clogging problems. The primary objectives of this study are (1) to understand the major factors controlling precipitation, heterogeneous nucleation,more » and growth phenomena of relatively insoluble aluminosilicates; (2) to determine the role of organics for inhibiting aluminosilicate formation, and (3) to develop a predictive tool to control precipitation, scale formation, and cementation under tank waste processing conditions. The results of this work will provide crucial information for (1) avoiding problematical sludge processing steps and (2) identifying and developing effective technologies to process retrieved sludges and supernatants before ultimate vitrification of wastes.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab., Richland, WA; Savannah River Technology Center, Aiken, SC; Princeton University, Princeton, NJ (US)
Sponsoring Org.:
USDOE Office of Environmental Management (EM) (US)
OSTI Identifier:
834764
Report Number(s):
EMSP-81887-2002
R&D Project: EMSP 81887; TRN: US0407333
DOE Contract Number:  
FG07-01ER14929
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 Jun 2002
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 36 MATERIALS SCIENCE; 54 ENVIRONMENTAL SCIENCES; BUILDUP; DEPOSITION; EVAPORATION; EVAPORATORS; FOULING; GLASS; LEACHING; NUCLEATION; PRECIPITATION; SLUDGES; SOLUBILITY; STABILITY; TANKS; THERMODYNAMICS; VITRIFICATION; WASHING; WASTE PROCESSING

Citation Formats

Mattigod, Shas V, Hobbs, David T, Wang, Li-Qiong, Dabbs, Daniel M, and Aksay, Ilhan A. Precipitation and Deposition of Aluminum-Containing Species in Tank Wastes. United States: N. p., 2002. Web. doi:10.2172/834764.
Mattigod, Shas V, Hobbs, David T, Wang, Li-Qiong, Dabbs, Daniel M, & Aksay, Ilhan A. Precipitation and Deposition of Aluminum-Containing Species in Tank Wastes. United States. https://doi.org/10.2172/834764
Mattigod, Shas V, Hobbs, David T, Wang, Li-Qiong, Dabbs, Daniel M, and Aksay, Ilhan A. 2002. "Precipitation and Deposition of Aluminum-Containing Species in Tank Wastes". United States. https://doi.org/10.2172/834764. https://www.osti.gov/servlets/purl/834764.
@article{osti_834764,
title = {Precipitation and Deposition of Aluminum-Containing Species in Tank Wastes},
author = {Mattigod, Shas V and Hobbs, David T and Wang, Li-Qiong and Dabbs, Daniel M and Aksay, Ilhan A},
abstractNote = {Aluminum-containing phases represent the most prevalent solids that can appear or disappear during the processing of radioactive tank wastes. Processes such as sludge washing and leaching are designed to dissolve Al-containing phases and thereby minimize the volume of high-level waste glass required to encapsulate radioactive sludges. Unfortunately, waste-processing steps that include evaporation can involve solutions that are supersaturated with respect to cementitious aluminosilicates that result in unwanted precipitation and scale formation. Of all the constituents of tank waste, limited solubility cementitious aluminosilicates have the greatest potential for clogging pipes and transfer lines, fouling highly radioactive components such as ion exchangers, and completely shutting down processing operations. For instance, deposit buildup and clogged drain lines experienced during the tank waste volume-reduction process at the Savannah River Site (SRS) required an evaporator to be shut down in October 1999. The Waste Processing Technology Section of Westinghouse Savannah River Company at SRS now is collaborating with team members from Pacific Northwest National Laboratory (PNNL) to verify the thermodynamic stability of aluminosilicate compounds under waste tank conditions in an attempt to solve the deposition and clogging problems. The primary objectives of this study are (1) to understand the major factors controlling precipitation, heterogeneous nucleation, and growth phenomena of relatively insoluble aluminosilicates; (2) to determine the role of organics for inhibiting aluminosilicate formation, and (3) to develop a predictive tool to control precipitation, scale formation, and cementation under tank waste processing conditions. The results of this work will provide crucial information for (1) avoiding problematical sludge processing steps and (2) identifying and developing effective technologies to process retrieved sludges and supernatants before ultimate vitrification of wastes.},
doi = {10.2172/834764},
url = {https://www.osti.gov/biblio/834764}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Jun 01 00:00:00 EDT 2002},
month = {Sat Jun 01 00:00:00 EDT 2002}
}