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Title: Salt splitting using ceramic membranes

Abstract

Many radioactive aqueous wastes in the DOE complex have high concentrations of sodium that can negatively affect waste treatment and disposal operations. Sodium can decrease the durability of waste forms such as glass and is the primary contributor to large disposal volumes. Waste treatment processes such as cesium ion exchange, sludge washing, and calcination are made less efficient and more expensive because of the high sodium concentrations. Pacific Northwest National Laboratory (PNNL) and Ceramatec Inc. (Salt Lake City UT) are developing an electrochemical salt splitting process based on inorganic ceramic sodium (Na), super-ionic conductor (NaSICON) membranes that shows promise for mitigating the impact of sodium. In this process, the waste is added to the anode compartment, and an electrical potential is applied to the cell. This drives sodium ions through the membrane, but the membrane rejects most other cations (e.g., Sr{sup +2}, Cs{sup +}). The charge balance in the anode compartment is maintained by generating H{sup +} from the electrolysis of water. The charge balance in the cathode is maintained by generating OH{sup {minus}}, either from the electrolysis of water or from oxygen and water using an oxygen cathode. The normal gaseous products of the electrolysis of water are oxygenmore » at the anode and hydrogen at the cathode. Potentially flammable gas mixtures can be prevented by providing adequate volumes of a sweep gas, using an alternative reductant or destruction of the hydrogen as it is generated. As H{sup +} is generated in the anode compartment, the pH drops. The process may be operated with either an alkaline (pH>12) or an acidic anolyte (pH <1). The benefits of salt splitting using ceramic membranes are (1) waste volume reduction and reduced chemical procurement costs by recycling of NaOH; and (2) direct reduction of sodium in process streams, which enhances subsequent operations such as cesium ion exchange, calcination, and vitrification.« less

Authors:
 [1]
  1. Pacific Northwest National Lab., Richland, WA (United States)
Publication Date:
Research Org.:
Science, Inc., Anaheim, CA (United States)
OSTI Identifier:
527202
Report Number(s):
PNNL-SA-28461-Rev.1; CONF-970148-Rev.1
Journal ID: ISSN 0149--6395; ON: DE97052111; TRN: 97:015045
Resource Type:
Conference
Resource Relation:
Journal Volume: 32; Journal Issue: 1-4; Conference: Efficient Separations and Processing (ESP) Crosscutting Program FY 1997 technical exchange meeting, Gaithersburg, MD (United States), 28-30 Jan 1997; Other Information: PBD: [1997]; Related Information: Is Part Of Proceedings of the efficient separations and processing crosscutting program 1997 technical exchange meeting; Gephart, J.M. [ed.]; PB: 211 p.
Country of Publication:
United States
Language:
English
Subject:
05 NUCLEAR FUELS; SODIUM; SEPARATION PROCESSES; HIGH-LEVEL RADIOACTIVE WASTES; RADIOACTIVE WASTE PROCESSING; ELECTROCHEMISTRY; CERAMICS; MEMBRANES

Citation Formats

Kurath, D E. Salt splitting using ceramic membranes. United States: N. p., 1997. Web. doi:10.1080/01496399708003215.
Kurath, D E. Salt splitting using ceramic membranes. United States. doi:10.1080/01496399708003215.
Kurath, D E. Wed . "Salt splitting using ceramic membranes". United States. doi:10.1080/01496399708003215. https://www.osti.gov/servlets/purl/527202.
@article{osti_527202,
title = {Salt splitting using ceramic membranes},
author = {Kurath, D E},
abstractNote = {Many radioactive aqueous wastes in the DOE complex have high concentrations of sodium that can negatively affect waste treatment and disposal operations. Sodium can decrease the durability of waste forms such as glass and is the primary contributor to large disposal volumes. Waste treatment processes such as cesium ion exchange, sludge washing, and calcination are made less efficient and more expensive because of the high sodium concentrations. Pacific Northwest National Laboratory (PNNL) and Ceramatec Inc. (Salt Lake City UT) are developing an electrochemical salt splitting process based on inorganic ceramic sodium (Na), super-ionic conductor (NaSICON) membranes that shows promise for mitigating the impact of sodium. In this process, the waste is added to the anode compartment, and an electrical potential is applied to the cell. This drives sodium ions through the membrane, but the membrane rejects most other cations (e.g., Sr{sup +2}, Cs{sup +}). The charge balance in the anode compartment is maintained by generating H{sup +} from the electrolysis of water. The charge balance in the cathode is maintained by generating OH{sup {minus}}, either from the electrolysis of water or from oxygen and water using an oxygen cathode. The normal gaseous products of the electrolysis of water are oxygen at the anode and hydrogen at the cathode. Potentially flammable gas mixtures can be prevented by providing adequate volumes of a sweep gas, using an alternative reductant or destruction of the hydrogen as it is generated. As H{sup +} is generated in the anode compartment, the pH drops. The process may be operated with either an alkaline (pH>12) or an acidic anolyte (pH <1). The benefits of salt splitting using ceramic membranes are (1) waste volume reduction and reduced chemical procurement costs by recycling of NaOH; and (2) direct reduction of sodium in process streams, which enhances subsequent operations such as cesium ion exchange, calcination, and vitrification.},
doi = {10.1080/01496399708003215},
journal = {},
issn = {0149--6395},
number = 1-4,
volume = 32,
place = {United States},
year = {1997},
month = {10}
}

Conference:
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