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Title: Chemical Oxygen Demand (COD) For Monitoring Reduction-Oxidation (Redox) Equilibrium During High Level Waste (HLW) Vitrification

Abstract

High-level nuclear waste is being immobilized at the Savannah River Site by vitrification into borosilicate glass at the Defense Waste Processing Facility. Control of the REDuction/OXidation (REDOX) equilibrium in the DWPF melter is critical for processing high level liquid wastes. Based upon previous research, an acceptable iron REDOX ratio was defined for the DWPF melts as 0.09 Fe2/SFe 0.33. Controlling the DWPF melter at a REDuction/OXidation (REDOX) equilibrium ofFe2/SFe 0.33 prevents the potential for metallic and metallic sulfide species to form and accumulate on the floor of the melter. Control of foaming due to deoxygenation of manganic species is achieved by converting 66-100 of the MnO2 or Mn2O3 species in a waste feed to MnO before the waste is fed to the DWPF melter. At the lower redox limit of Fe 2/SFe 0.09 about 99 of the Mn 4/Mn 3 is converted to Mn 2. Therefore, the lower REDOX limit eliminates melter foaming from deoxygenation. Organic and nitrate concentrations in the DWPF melter feed are the major parameters influencing melt REDOX. Organics such as formates act as reductants while nitrates, nitrites, and manganic (Mn 4 and Mn 3) species act as oxidants. During melting, the REDOX of the melt poolmore » cannot be measured. Therefore, the Fe 2/SFe ratio in the glass poured from the melter must be related to melter feed organic and oxidant concentrations to ensure production of a high quality glass without impacting production rate (e.g., from foaming) or melter life (e.g., from metal formation and accumulation).« less

Authors:
Publication Date:
Research Org.:
Savannah River Site (SRS), Aiken, SC (United States)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
829692
Report Number(s):
WSRC-TR-2003-00322
TRN: US0405805
DOE Contract Number:  
AC09-96SR18500
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 30 Apr 2004
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 54 ENVIRONMENTAL SCIENCES; BOROSILICATE GLASS; CHEMICAL OXYGEN DEMAND; FORMATES; GLASS; IRON; LIQUID WASTES; MELTING; MONITORING; NITRATES; NITRITES; OXIDIZERS; RADIOACTIVE WASTES; SULFIDES; VITRIFICATION; WASTE PROCESSING; DWPF; SLUDGE BATCH 3; COAL; OXALATE; FORMATE; NITRATE; OXIDATION; REDUCTION.

Citation Formats

JANTZEN, CAROLM. Chemical Oxygen Demand (COD) For Monitoring Reduction-Oxidation (Redox) Equilibrium During High Level Waste (HLW) Vitrification. United States: N. p., 2004. Web. doi:10.2172/829692.
JANTZEN, CAROLM. Chemical Oxygen Demand (COD) For Monitoring Reduction-Oxidation (Redox) Equilibrium During High Level Waste (HLW) Vitrification. United States. https://doi.org/10.2172/829692
JANTZEN, CAROLM. 2004. "Chemical Oxygen Demand (COD) For Monitoring Reduction-Oxidation (Redox) Equilibrium During High Level Waste (HLW) Vitrification". United States. https://doi.org/10.2172/829692. https://www.osti.gov/servlets/purl/829692.
@article{osti_829692,
title = {Chemical Oxygen Demand (COD) For Monitoring Reduction-Oxidation (Redox) Equilibrium During High Level Waste (HLW) Vitrification},
author = {JANTZEN, CAROLM},
abstractNote = {High-level nuclear waste is being immobilized at the Savannah River Site by vitrification into borosilicate glass at the Defense Waste Processing Facility. Control of the REDuction/OXidation (REDOX) equilibrium in the DWPF melter is critical for processing high level liquid wastes. Based upon previous research, an acceptable iron REDOX ratio was defined for the DWPF melts as 0.09 Fe2/SFe 0.33. Controlling the DWPF melter at a REDuction/OXidation (REDOX) equilibrium ofFe2/SFe 0.33 prevents the potential for metallic and metallic sulfide species to form and accumulate on the floor of the melter. Control of foaming due to deoxygenation of manganic species is achieved by converting 66-100 of the MnO2 or Mn2O3 species in a waste feed to MnO before the waste is fed to the DWPF melter. At the lower redox limit of Fe 2/SFe 0.09 about 99 of the Mn 4/Mn 3 is converted to Mn 2. Therefore, the lower REDOX limit eliminates melter foaming from deoxygenation. Organic and nitrate concentrations in the DWPF melter feed are the major parameters influencing melt REDOX. Organics such as formates act as reductants while nitrates, nitrites, and manganic (Mn 4 and Mn 3) species act as oxidants. During melting, the REDOX of the melt pool cannot be measured. Therefore, the Fe 2/SFe ratio in the glass poured from the melter must be related to melter feed organic and oxidant concentrations to ensure production of a high quality glass without impacting production rate (e.g., from foaming) or melter life (e.g., from metal formation and accumulation).},
doi = {10.2172/829692},
url = {https://www.osti.gov/biblio/829692}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Apr 30 00:00:00 EDT 2004},
month = {Fri Apr 30 00:00:00 EDT 2004}
}