Solid-solute phase equilibria in aqueous solution. 5: The system CdCO sub 3 -CaCO sub 3 -CO sub 2 -H sub 2 O
Journal Article
·
· Geochimica et Cosmochimica Acta; (United States)
- Abteilung fuer Physikalische Chemie, Leoben (Austria)
- Veitscher Magnesitwerke-A.-G., Leoben (Austria)
The system CdCO{sub 3}-CaCO{sub 3}-CO{sub 2}-H{sub 2}O was investigated potentiometrically at 25C and 1 atm total pressure. Cd{sub (1-x)}Ca{sub x}CO{sub 3} solid solutions were prepared over the entire compositional range. Aqueous solutions were kept at constant ionic strength I = 3 mol (Na)ClO{sub 4}/kg H{sub 2}O. Experimental results were depicted in Lippmann (x {minus} x{sup aq} {minus} log {Sigma} *K{sub ps0}) diagrams. The solutus was investigated by pH and Cd{sup 2+} sensitive electrodes and it turned out that the solid solutions neither dissolved congruently nor attained stable equilibrium with aqueous solutions within one week of observation. Consequently, the excess Gibbs energy of mixing of otavite and calcite was determined by a method of successive approximations. Aqueous solutions were presaturated to the supposed equilibrium composition prior to equilibration with solid solutions, and constant pH values, corresponding to constant log {Sigma} *K{sub ps0} values, indicated stable equilibrium. A recently proposed technique of sequential Bayesian excess parameter estimation was employed for data evaluation which led to the conclusion that the otavite-calcite solid solution series has ideal mixing properties.
- OSTI ID:
- 7235621
- Journal Information:
- Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 55:12; ISSN GCACA; ISSN 0016-7037
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
58 GEOSCIENCES
580000* -- Geosciences
AQUEOUS SOLUTIONS
CADMIUM CARBONATES
CADMIUM COMPOUNDS
CALCITE
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONATE MINERALS
CARBONATES
CHALCOGENIDES
CHEMISTRY
DIAGRAMS
DISPERSIONS
ENERGY
EQUILIBRIUM
FORMATION FREE ENTHALPY
FREE ENTHALPY
GEOCHEMISTRY
HYDROGEN COMPOUNDS
ION EXCHANGE
MINERALS
MIXTURES
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PHASE DIAGRAMS
PHASE STUDIES
PHYSICAL PROPERTIES
POTENTIOMETRY
SOLID SOLUTIONS
SOLUBILITY
SOLUTIONS
STOICHIOMETRY
THERMODYNAMIC ACTIVITY
THERMODYNAMIC PROPERTIES
TITRATION
WATER
580000* -- Geosciences
AQUEOUS SOLUTIONS
CADMIUM CARBONATES
CADMIUM COMPOUNDS
CALCITE
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONATE MINERALS
CARBONATES
CHALCOGENIDES
CHEMISTRY
DIAGRAMS
DISPERSIONS
ENERGY
EQUILIBRIUM
FORMATION FREE ENTHALPY
FREE ENTHALPY
GEOCHEMISTRY
HYDROGEN COMPOUNDS
ION EXCHANGE
MINERALS
MIXTURES
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PHASE DIAGRAMS
PHASE STUDIES
PHYSICAL PROPERTIES
POTENTIOMETRY
SOLID SOLUTIONS
SOLUBILITY
SOLUTIONS
STOICHIOMETRY
THERMODYNAMIC ACTIVITY
THERMODYNAMIC PROPERTIES
TITRATION
WATER