Simultaneous use of isothermal, nonisothermal, and constant rate thermal analysis (CRTA) for discerning the kinetics of the thermal dissociation of smithsonite

✍ Scribed by F. J. Gotor; M. Macías; A. Ortega; J. M. Criado

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 185 KB
• Volume: 30
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/(sici)1097-4601(1998)30:9<647::aid-kin6>3.0.co;2-s

✦ Synopsis

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 approximately, an kinetic model describes the reaction, whereas, at temperatures 650 K, A 0.5 roughly higher than the above reaction obeys a F 1 kinetic law. An interpretation of this 690 K behavior is given.