Study on the thermal decomposition kinetics of nano-sized calcium carbonate.
This study of the thermal decomposition kinetics of various average diameter nano-particles of calcium carbonate by means of TG-DTA ( thermogravimetry and differential thermal analysis) showed that the thermal decomposition kinetic mechanisms of the same crystal type of calcium carbonate samples do not vary with decreasing of their average diameters; their pseudo-active energy (a); and that the top-temperature of decomposition T(p) decreases gently in the scope of micron-sized diameter, but decreases sharply when the average diameter decreases from micron region to nanometer region. The extraordinary properties of nano-particles were explored by comparing the varying regularity of the mechanisms and kinetic parameters of the solid-phase reactions as well as their structural characterization with the variation of average diameters of particles. These show that the aggregation, surface effect as well as internal aberrance and stress of the nano-particles are the main reason causing both E(a) and T(p) to decline sharply with the decrease of the average diameter of nano-particles.
Li
Dai-Xi
DX
Chemistry Department, Guizhou University, Guizhou 550025, China. dxli75@sohu.com
Shi
Hong-Yun
HY
Jie
Deng
D
Xu
Yuan-Zhi
YZ
D002119:Calcium Carbonate / Q000737:chemistry*; D003461:Crystallography / Q000379:methods*; D004735:Energy Transfer; D006358:Hot Temperature; D007700:Kinetics; D008422:Materials Testing; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D044367:Phase Transition; D013223:Statistics as Topic; D013329:Structure-Activity Relationship; D044366:Transition Temperature
D002119:Calcium Carbonate