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Simultaneous use of isothermal, nonisothermal, and constant rate thermal analysis (CRTA) for discerning the kinetics of the thermal dissociation of smithsonite
Author(s) -
Gotor F. J.,
Macías M.,
Ortega A.,
Criado J. M.
Publication year - 1998
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/(sici)1097-4601(1998)30:9<647::aid-kin6>3.0.co;2-s
Subject(s) - chemistry , isothermal process , thermodynamics , thermal decomposition , reaction rate constant , anhydrous , kinetics , thermal analysis , thermal , dissociation (chemistry) , organic chemistry , physics , quantum mechanics
The mechanism of the thermal decomposition of smithsonite has been determined from a comparison of the results obtained from isothermal, linear heating rate (TG), and Constant Rate Thermal Analysis (CRTA) experiments. Two important precautions have been taken in this work. Firstly, the chemical composition of the sample has been checked in order to be sure that pure anhydrous zinc carbonate has been used. Secondly, the experimental conditions have been selected in such a way to avoid the influence of heat and mass transfer phenomena on the forward reaction. It has been shown that the mechanism for the thermal decomposition of smithsonite depends upon temperature. Thus, at temperatures lower than 650 K, approximately, an A 0.5 kinetic model describes the reaction, whereas, at temperatures roughly higher than 690 K the above reaction obeys a F 1 kinetic law. An interpretation of this behavior is given. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet: 30: 647–655, 1998