Soret diffusion processes in aqueous sodium chloride solutions
The mass transport of chemical species induced by a temperature gradient, commonly known as Soret diffusion, has been examined for the case of the sodium chloride and water system. The occurrence of significant thermal gradients in geological media, especially those associated with radioactive waste disposal sites, can produce a measurable flux of sodium chloride and therefore enrich the local solutions. Soret coefficients, or the ratio of thermal to isothermal mass transport factors, describe this rate of mass transfer and are necessary for evaluating certain nonequilibrium processes, such as the migration of fluid inclusions in rock salt. Experimental Soret coefficients for the NaCl-H/sub 2/O system were obtained by the use of a conductimetric thermal diffusion cell. This approach relies on monitoring the electrical conductivity change of two separate isothermal reservoirs which are maintained at different temperatures. The Soret cell is situated between the reservoirs and is comprised of an inert matrix of glass beads in order to minimize any solution convection. The utilization of this porous medium requires corrections for porosity and tortuosity. Measurements were made for 0.1 and 1.0 N NaCl solutions at mean temperatures of 40/sup 0/C and 50/sup 0/C with the mass transport induced by a thermal gradient of 2.6/sup 0/C/cm. The preliminary results indicate a Soret separation on the order of 1 to 2 percent with the attainment of a steady state in approximately 15 hours.
- Research Organization:
- Sandia National Laboratories, Albuquerque, NM (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6917427
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
RADIOACTIVE WASTE FACILITIES
MASS TRANSFER
RADIONUCLIDE MIGRATION
THERMAL DIFFUSION
RADIOACTIVE WASTES
UNDERGROUND DISPOSAL
MIGRATION
POROSITY
RADIOACTIVE WASTE DISPOSAL
SALT DEPOSITS
SITE CHARACTERIZATION
SODIUM CHLORIDES
STEADY-STATE CONDITIONS
TEMPERATURE GRADIENTS
ALKALI METAL COMPOUNDS
CHLORIDES
CHLORINE COMPOUNDS
DIFFUSION
ENVIRONMENTAL TRANSPORT
GEOLOGIC DEPOSITS
HALIDES
HALOGEN COMPOUNDS
MANAGEMENT
MATERIALS
NUCLEAR FACILITIES
RADIOACTIVE MATERIALS
SODIUM COMPOUNDS
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
052002* - Nuclear Fuels- Waste Disposal & Storage