Reactions between technetium in solution and iron-containing minerals under oxic and anoxic conditions

Journal Article · Sun Jan 01 04:00:00 EST 1984 · ACS Symp. Ser.; (United States)

DOI:https://doi.org/10.1021/bk-1984-0246.ch002· OSTI ID:6820248

Vandergraaf, T T; Ticknor, K V; George, I M

The behavior of technetium in the geosphere is of particular importance in nuclear fuel waste management studies because this man-made element has a long half-life and, under ambient conditions in the laboratory, is not readily sorbed on geologic materials. Autoradiographic analyses of rock and mineral thin sections contacted with /sup 95/TcO/sub 4//sup -/-containing solutions, under oxic and anoxic conditions, have confirmed that virtually no sorption takes place in the presence of oxygen. However, under anoxic conditions (< 0.2 ..mu..g/g oxygen in the atmosphere), sorption of technetium was observed on iron-oxide inclusions in ferrous-iron-containing minerals (biotite, and olivine, pyroxene, hornblende) and on iron-oxide coatings on microfractures in granite, but not on the ferrous-iron minerals within the granite themselves. Subsequent static sorption tests with crushed magnetite showed that sorption is a function of the composition of the solution and of the radionuclide concentration, and again occurred only in the absence of oxygen. This behavior is in contrast with that observed with metallic iron, which sorbs technetium strongly, even in the presence of air. These results show that technetium can be contained by magnetite in the geosphere, provided reducing conditions can be maintained. This can be aided, for example, by the incorporation of iron or iron oxides in the buffer and backfill materials in the waste disposal vault. 11 references, 8 figures, 6 tables.

• Research Organization: Atomic Energy of Canada Ltd., Pinawa, Manitoba
• OSTI ID: 6820248
• Journal Information: ACS Symp. Ser.; (United States), Journal Name: ACS Symp. Ser.; (United States) Vol. 246; ISSN ACSMC
• Country of Publication: United States
• Language: English

Related Subjects

052002* -- Nuclear Fuels-- Waste Disposal &amp; Storage
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ALKALINE EARTH METAL COMPOUNDS
AMPHIBOLE
BIOTITE
CATALYTIC EFFECTS
CHALCOGENIDES
CONTROL
ELEMENTS
ENVIRONMENTAL TRANSPORT
HORNBLENDE
IRON COMPOUNDS
IRON ORES
IRON OXIDES
IRON SILICATES
MAGNESIUM COMPOUNDS
MAGNESIUM SILICATES
MAGNETITE
MANAGEMENT
MASS TRANSFER
METALS
MICA
MINERALS
NONMETALS
OLIVINE
ORES
OXIDE MINERALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PYROXENES
QUANTITY RATIO
RADIOACTIVE WASTE MANAGEMENT
RADIOACTIVE WASTE STORAGE
RADIONUCLIDE MIGRATION
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SORPTION
SORPTIVE PROPERTIES
STORAGE
SURFACE PROPERTIES
TECHNETIUM
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
WASTE MANAGEMENT
WASTE STORAGE