Rate and activation enthalpy of decomposition of CaCO/sub 3/

Journal Article · Mon Sep 01 04:00:00 EDT 1980 · Metall. Trans.; (United States)

OSTI ID:6268607

Powell, E K; Searcy, A W

The heat balance during steady state decomposition of CaCO/sub 3/ single crystals in vacuum is analyzed. It is shown that, contrary to the contention of others, the rate of decomposition of CaCO/sub 3/ can be measured under conditions which make the slowest chemical step of the process, rather than heat transfer or gas phase diffusion, rate limiting. From new experimental measurements and measurements of previous investigators the apparent enthalpy of activation for CaCO/sub 3/ decomposition (when the CO/sub 2/ background pressure is negligible) is found to be 50 +- 3 kcal (calculated in terms of pressures equivalent to the CO/sub 2/ decomposition flux densities), compared to 40.5 kcal for the equilibrium decomposition reaction. The rates of decomposition of single crystals which are measured in different studies differ by as much as a factor of 4, but average only about 10/sup -5/ times the flux densities that are theoretically achievable for the reaction. 3 figures, 1 table.

• Research Organization: Lawrence Berkeley Lab., CA
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6268607
• Journal Information: Metall. Trans.; (United States), Journal Name: Metall. Trans.; (United States) Vol. 11B; ISSN MTGTB
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ACTIVATION ENERGY
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATES
CHEMICAL REACTIONS
CRYSTALS
DECOMPOSITION
ENERGY
ENERGY TRANSFER
ENTHALPY
HEAT TRANSFER
KINETICS
MONOCRYSTALS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REACTION KINETICS
THERMODYNAMIC PROPERTIES