Effect of CO/sub 2/ pressure on the rate of decomposition of calcite (CaCO/sub 3/)

Technical Report · Tue Jan 01 04:00:00 EST 1980

OSTI ID:5740687

Darroudi, T

The Langmuir method was employed to measure the rate of CO/sub 2/ escape from (1011) cleavage surfaces of calcite (CaCO/sub 3/) single crystals at temperatures from 893/sup 0/K to 1073/sup 0/K and at background pressures of CO/sub 2/ from 10/sup -5/P/sub eq/ to 4 x 10/sup -2/P/sub eq/, where P/sub eq/ is the equilibrium decomposition pressure. Rates of decomposition measured in vacuum were in good agreement with earlier studies carried out under similar conditions. The rates were relatively sensitive to the CO/sub 2/ pressure at pressures of the order of 10/sup -2/P/sub eq/, but were essentially independent of CO/sub 2/ pressure for a range of lower pressures that cause a flux of CO/sub 2/ gas against the CaCO/sub 3/ sample surface up to about 10/sup 3/ times the flux that leaves the CaCO/sub 3/ in vacuum. In this latter CO/sub 2/ pressure range, the rate limiting process is probably a solid state diffusional step or surface step of CO/sub 2/. The rate limiting process at CO/sub 2/ pressures near P/sub eq/ must be different, but more data are needed to determine what that process may be.

• Research Organization: California Univ., Berkeley (USA). Lawrence Berkeley Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5740687
• Report Number(s): LBL-10309
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATES
CHEMICAL REACTIONS
CRYSTALS
DECOMPOSITION
HIGH TEMPERATURE
MONOCRYSTALS
OXYGEN COMPOUNDS
PRESSURE DEPENDENCE
VERY HIGH TEMPERATURE