Calcium molybdate solubility in spent oil shale and a preliminary evaluation of the association constants for the formation of CaMoO sub 4 sup 0 (aq), KMoO sub 4 sup minus (aq), and NaMoO sub 4 sup minus (aq)

Journal Article · Thu Feb 01 04:00:00 EST 1990 · Environmental Science and Technology; (United States)

DOI:https://doi.org/10.1021/es00072a010· OSTI ID:5499707

Essington, M E ^[1]

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1. Univ. of Wyoming Research Corp., Laramie (USA)

In order to better understand the fate and behavior of molybdenum in spent oil shale disposal environments, the equilibrium solubility of CaMoO{sub 4} (c, powellite) in deionized-distilled water, potassium nitrate solutions, and spent oil shale leachates was determined. The calculated log K{sub sp} for the dissolution of CaMoO{sub 4}(c) is {minus}8.05. The ion association constants for the formation of CaMoO{sub 4}{sup 0}(aq) and KMoO{sub 4}{sup {minus}}(aq) were also determined by using an iterative estimation technique. The estimate of log Q for the formation of CaMoO{sub 4}{sup 0}(aq) is 3.09. Similarly, an estimate of log Q for the formation of KMoO{sub 4}{sup {minus}}(aq) is 1.29. Calcium molybdate solubility in CaMoO{sub 4}(c)-spiked and nonspiked spent oil shale equilibrium solutions was evaluated. The CaMoO{sub 4}(c)-spiked spent oil shale solutions were initially evaluated as supersaturated with respect to CaMoO{sub 4}(c). Evaluation of the data indicated that the NaMoO{sub 4}{sup {minus}}(aq) ion pair may significantly contribute to total soluble molybdenum. The spiked spent oil shale solution data are used to generate a log Q of 1.66 for the formation of NaMoO{sub 4}{sup {minus}}(aq). Inclusion of this species in the geochemical model analyses of the spiked spent oil shale solutions suggests that the solutions are in equilibrium with CaMoO{sub 4}(c). Geochemical model analyses show that CaMoO{sub 4}(c) does not control molybdenum concentrations in the spent oil shale (nonspiked) equilibrium solutions. Further, these data suggest that CaMoO{sub 4}(c) may not occur in spent oil shales.

• OSTI ID: 5499707
• Journal Information: Environmental Science and Technology; (United States), Journal Name: Environmental Science and Technology; (United States) Vol. 24:2; ISSN ESTHA; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
041000* -- Oil Shales & Tar Sands-- Environmental Aspects
ALKALI METAL COMPOUNDS
ALKALINE EARTH METALS
BITUMINOUS MATERIALS
CALCIUM
CARBONACEOUS MATERIALS
DISPERSIONS
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
GROUND DISPOSAL
HYDROGEN COMPOUNDS
LEACHATES
MANAGEMENT
MATERIALS
METALS
MIXTURES
MOLYBDATES
MOLYBDENUM COMPOUNDS
NITRATES
NITROGEN COMPOUNDS
OIL SHALES
OXYGEN COMPOUNDS
POTASSIUM COMPOUNDS
POTASSIUM NITRATES
REFRACTORY METAL COMPOUNDS
ROCKS
SEDIMENTARY ROCKS
SHALES
SOLUBILITY
SOLUTIONS
TRANSITION ELEMENT COMPOUNDS
WASTE DISPOSAL
WASTE MANAGEMENT
WATER