Impact of oxidation and reduction on the leaching potential of trace metals from spent oil shale. [Reducing and oxidizing environment]
The long-term quality of water produced at spent oil shale disposal facilities is a critical concern. Understanding the release and mobility of trace elements as natural weathering of the disposal pile occurs is particularly important. Because spent oil shale leachates are highly alkaline, weathering reactions that increase leachate acidity, thus trace element release and mobility, must be characterized. In order to simulate weathering environments that would occur in a waste disposal pile (i.e., saturated and unsaturated groundwater environments), spent oil shale has been leached under saturated and unsaturated conditions. Unsaturated conditions (an oxidizing environment) allow the oxidation of iron sulfides and adsorption of carbon dioxide. Saturated leaching conditions (a reducing environment) should not allow the acid generation by oxidation or carbon dioxide adsorption. Both of these conditions generate hydrogen ions and should reduce pH in spent oil shale leachate. Spent oil shale was leached for six weeks and the leachate analyzed for pH, sulfates, arsenic, boron, cadimum, calcium, copper, lithium, magnesium, manganese, sodium, strontium, and zinc. The leaching studies indicate that the oxidizing simulation did not significantly decrease the leachate pH, and under reducing conditions the greatest concentration of trace elements were leached from the shale. The trace elements extracted from the spent oil shale in the greatest concentrations are all soluble in high pH solutions. These results indicate that spent oil shale disposal piles in arid to semiarid environments may maintain an alkaline pH because of an extremely high alkaline buffering capacity. These data also indicate that research on carbon dioxide absorption is needed to assess the long-term contribution of acidity to modify solution pH and trace element mobility. 15 refs., 2 tabs.
- Research Organization:
- Western Research Inst., Laramie, WY (USA)
- DOE Contract Number:
- FC21-83FE60177
- OSTI ID:
- 6985012
- Report Number(s):
- DOE/FE/60177-2303; ON: DE87008056
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
Similar Records
Development of a technical approach for assessing environmental release and migration characteristics of Hanford Grout
Leach potential of processed shale as determined by two extraction methods
Related Subjects
ARSENIC
LEACHING
BORON
CADMIUM
CALCIUM
COPPER
LEACHATES
CHEMICAL COMPOSITION
PH VALUE
LITHIUM
MAGNESIUM
MANGANESE
SODIUM
SPENT SHALES
STRONTIUM
SULFATES
ZINC
EXPERIMENTAL DATA
OXIDATION
REDUCTION
WASTE DISPOSAL
WEATHERING
ALKALI METALS
ALKALINE EARTH METALS
CHEMICAL REACTIONS
DATA
DISPERSIONS
DISSOLUTION
ELEMENTS
INFORMATION
MANAGEMENT
METALS
MIXTURES
NUMERICAL DATA
OXYGEN COMPOUNDS
SEMIMETALS
SEPARATION PROCESSES
SOLUTIONS
SULFUR COMPOUNDS
TRANSITION ELEMENTS
WASTE MANAGEMENT
040900* - Oil Shales & Tar Sands- Waste management