A Comprehensive Study of the Solubility, Thermochemistry, Ion Exchange and Precipitation Kinetics of NO3 Cancrinite and No3 Sodalite

Technical Report · Fri Dec 31 00:00:00 EST 2004

DOI:https://doi.org/10.2172/839384· OSTI ID:839384

Jove-Colon, Carlos; Navrotsky, Alexandra

The precipitation of aluminosilicate phases from caustic nuclear wastes has proven to be problematic in a number of processes including radionuclide separations (cementation of columns by aluminosilicate phases), tank emptying (aluminosilicate tank heels), and condensation of wastes in evaporators (aluminosilicate precipitates in the evaporators, providing nucleation sites for growth of critical masses of radioactive actinide salts). In a collaboration between SNL and UCD, we have investigated why and how these phases form, and which conditions favor the formation of which phases. These studies have involved synthesis and characterization of aluminosilicate phases formed using a variety of synthesis techniques, kinetics of precipitation, structural investigations of aluminosilicate phases, thermodynamic calculations of aluminosilicate solubility, calorimetric studies of aluminosilicate precipitation, and a limited investigation of radionuclide partitioning and ion exchange processes (involving typical tank fluid chemistries and these materials). The predominant phases that are observed in the aluminosilicate precipitates from basic tanks wastes (i.e. Hanford, Savannah River Site ''SRS'' wastes) are the salt enclathrated zeolites: sodium nitrate, sodium carbonate and sodium hydroxide sodalite and cancrinite. These phases precipitate readily from the high ionic strength, highly basic solutions at ambient temperatures as well as at elevated temperatures, with or without the presence of an external Al and Si source (both are contained in the waste solutions), and upon interactions with reactive soil components such as clays. This report focuses on the portion of the work performed at UC Davis by Professor Navrotsky's group.

• Research Organization: Sandia National Laboratories, Albuquerque, NM (US); University of California at Davis, Davis, CA (US)
• Sponsoring Organization: USDOE Office of Science (SC) (US)
• DOE Contract Number: FG07-01ER63298
• OSTI ID: 839384
• Report Number(s): EMSP-81959; R&D Project: EMSP 81959; TRN: US0501727
• Resource Relation: Other Information: PBD: 31 Dec 2004
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
54 ENVIRONMENTAL SCIENCES
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ACTINIDES
AMBIENT TEMPERATURE
ION EXCHANGE
KINETICS
NUCLEATION
PRECIPITATION
RADIOACTIVE WASTES
RADIOISOTOPES
SODIUM CARBONATES
SODIUM HYDROXIDES
SODIUM NITRATES
SOLUBILITY
SYNTHESIS
THERMODYNAMICS
ZEOLITES