ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Measurement of kinetics of thermal decomposition of calcium carbonate by a thermobalance with a quartz spiral and optical recording

I. Proks

Slovak Academy of Sciences, Bratislava 9

Abstract: The measurement of the kinetics of thermal decompn. of CaCO3 in a vacuum or at zero CO₂ partial pressure at 654°-756° by a thermobalance with a quartz spiral and optical recording is described. About 6 mg. pptd. CaCO₃ was heated and then activated by decompn. at 700° in a vacuum and by recarbonization at 650° and at a pressure of 50 torr CO_2. The detd. value of the formal order of the decompn. is close to 2/3 at all temps. so that the calcd. activation energy E = 42,000 ± 1100 cal. corresponds to the process in the phase boundary. It was detd. by the calcn. that the value E is equal to the activation energy of the thermal dissocn. of CaCO₃ if the model occurrence takes into consideration all assumed reactions in the phase boundary. This value was used in the calcn. of the relation of the surface molar breakdowns of the active CaO and CaCO₃ (α = 10-5), of the values of velocity consts. of the partial reactions in the phase boundary, and of the size of the effective surface of the sample (∼700 cm.2/g.). The value of the surface molar breakdown of the active CaO is changed very little in the equil. system CaO-CO₂ between 650° to 850°, but at the const. temp. it is dependent on the partial pressure of CO₂.

Full paper in Portable Document Format: 2010a697.pdf (in Slovak)

Chemical Papers 20 (10) 697–715 (1966)