Effect of CO/sub 2/ pressure on the rate of decomposition of calcite

Journal Article · Thu Dec 24 04:00:00 EST 1981 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j150626a004· OSTI ID:7060862

Darroudi, T; Searcy, A W

Rates of CO/sub 2/ escape from (1011) clevage surfaces of calcite (CaCO/sub 3/) single crystals were measured at temperatures from 893 to 1073 K and at CO/sub 2/ background pressures, P/sub CO/sub 2//, from

10/sup -2/P/sub eq/, but do not obey the parabolic rate law deduced by earlier investigators from data in a limited pressure range. For P/sub L/ < P /sub CO/sub 2// < 10/sup -2/P/sub eq/, the decomposition rates are essentially independent of P/sub CO/sub 2//, which implies that in this range the apparent activation enthalpy and entropy are unchanged from those measured under vacuum, ..delta..H* = 209 +/- 12 kJ (50 +/- 3 kcal) and ..delta..S* = 84 +/- 12 J/deg (20 +/- 3 cal/deg). The rate-limiting process in this pressure range is probably condensed-phase diffusion of CO/sub 2/ or a surface step for CO/sub 2/ prior to desorption.

• Research Organization: Lawrence Berkeley Lab., Berkeley, CA
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7060862
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 85:26; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical &amp; Spectral Procedures
400200 -- Inorganic
Organic
&amp; Physical Chemistry
ALKALINE EARTH METAL COMPOUNDS
CALCITE
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONATE MINERALS
CARBONATES
CHALCOGENIDES
CHEMICAL REACTIONS
CORRELATION FUNCTIONS
CRYSTAL STRUCTURE
DATA
DECOMPOSITION
DIAGRAMS
ENTHALPY
EQUATIONS
EXPERIMENTAL DATA
FLUID FLOW
FLUX DENSITY
FUNCTIONS
GAS FLOW
HIGH TEMPERATURE
INFORMATION
ISOTHERM
MINERALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PRESSURE DEPENDENCE
QUANTITY RATIO
SCATTERPLOTS
SULFATES
SULFUR COMPOUNDS
THERMODYNAMIC PROPERTIES
VERY HIGH TEMPERATURE