Solubility, mobility and plant uptake of toxic elements in retorted oil shales as affected by recarbonation

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5365209

Reddy, K J

The primary objective of this study was to develop a method of lowering the alkalinity of retorted shales and of reducing the solubility of toxic elements. The solubility relationships and mineral transformations associated with recarbonation of retorted shales were evaluated by determining the solubilities of different elements and by using X-ray diffraction analysis. An accurate method of measuring carbonate activity in shale extracts was developed. This method consisted of acidifying shale extracts with concentrated HCI. The evolved CO/sub 2/(g) was trapped in NaOH and titrated to pH 8.5. A computer speciation model was developed to calculate the equilibrium activities of different ions and the CO/sub 2/(g) partial pressure. Recarbonation dissolved silicates, restored the carbonate deficit, and lowered pH to near 8.5 when equilibrium with CaCO/sub 3/ and CO/sub 2/(g) partial pressure of approximately 10/sup -4.65/ atm. was attained. Furthermore, recarbonation decreased the solubilities of F, Ba, Cr, Sr, and Mo and lowered their concentrations in shale leachates, showing that recarbonation of spent shales can retard the movement of toxic elements into the groundwater. Tall wheatgrass (Agropyron elongatum) seeds placed in Lurgi shale without soil cover failed to germinate. On recarbonated Lurgi shale, plants grew normally without soil cover and accumulated normal levels of As, Se, Ba, B, Cu, Cd, Sr, and Ti. The results suggest that recarbonated retorted shales can be revegetated directly without a soil cover

• Research Organization: Colorado State Univ., Fort Collins (USA)
• OSTI ID: 5365209
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
041000* -- Oil Shales & Tar Sands-- Environmental Aspects
560300 -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALINE EARTH METALS
ARSENIC
BARIUM
BIOLOGICAL ACCUMULATION
BITUMINOUS MATERIALS
BORON
CADMIUM
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
COHERENT SCATTERING
COPPER
DIFFRACTION
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
GRASS
GROWTH
MATERIALS
METALS
OIL SHALES
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PLANT GROWTH
PLANTS
SCATTERING
SELENIUM
SEMIMETALS
SOLUBILITY
STRONTIUM
TITANIUM
TOXICITY
TRANSITION ELEMENTS
X-RAY DIFFRACTION