Kinetic and Thermodynamic Study of Calcite Marble Samples from Lesser Himalayas

A kinetic and thermodynamic study of selected calcite marble samples from Lesser Himalayas has been performed using thermogravimetric and differential thermal analyses at heating rates of (10,^{circ }mathrm{C},{cdot }min ^{-1}) and (30,^{circ }mathrm{C},{cdot }min ^{-1}) . The minero-petrography of calcite grains, phase analysis, chemical analysis, and minor impurities determination were carried out using thin-section polarized light microscopy, X-ray diffraction, X-ray fluorescence, and electron microprobe analysis, respectively. The calcite content of the investigated marble samples varied from 97.50 mass% to 98.70 mass%. The activation energy, (E_mathrm{a}) , for the decomposition process increased from (158.6,mathrm{kJ},{cdot }mathrm{mol}^{-1}) to (179.4,mathrm{kJ},{cdot },mathrm{mol}^{-1}) and from (214.1,mathrm{kJ},{cdot }, mathrm{mol}^{-1}) to (232.8,mathrm{kJ},{cdot }, mathrm{mol}^{-1}) for heating rates of (10,^{circ }mathrm{C},{cdot }, min ^{-1}) and (30,^{circ }mathrm{C},{cdot }, min ^{-1}) , respectively, with decreasing calcite content. The activation energy values obtained in the present study were in good agreement with previous studies.