A study of the thermal decomposition of BaCO3 |
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Authors: | I Arvanitidis Du Siche S Seetharaman |
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Affiliation: | 1. Theoretical Metallurgy Department, Royal Institute of Technology, S-100 44, Stockholm, Sweden
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Abstract: | In the present work, the decomposition reaction, BaCO3 (solid) = BaO (solid) + CO2 (gas), was investigated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) methods. Both shallow
powder beds and densely compacted spheres of the carbonate were employed. In the case of the shallow powder beds, TGA and
DTA were carried out simultaneously. The DTA curves showed that BaCO3 exhibited two phase transformations, the transformation of orthorhombic to hexagonal occurring at 1079 K and that of hexagonal
to cubic at 1237 K. The activation energy and the forward reaction rate constant of the decomposition of BaCO3 were evaluated from the thermogravimetric results of the powder beds. The activation energy of the decomposition was found
to be 305(± 14) kJ • mole−1. The experimental results obtained with the compacted spheres were compared with those corresponding to the powder beds.
After the initial stages, the formation of liquid due to the eutectic reaction between BaCO3 and BaO appears to play an important role in the reaction kinetics. |
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