Journal of Zhejiang University SCIENCE
(ISSN 1009-3095, Monthly)

2003   Vol. 4   No. 3   p.363-368


Study on the thermal decomposition kinetics of nano-sized calcium carbonate

LI Dai-xi(李代禧)(Chemistry Department, Guizhou University, Guizhou 550025, China;Chemistry Department, Zhejiang University, Hangzhou 310027, China)
SHI Hong-yun(史鸿运)(Chemistry Department, Guizhou University, Guizhou 550025, China)
DENG Jie(邓洁)(Chemistry Department, Guizhou University, Guizhou 550025, China)
XU Yuan-zhi(徐元植)(Chemistry Department, Zhejiang University, Hangzhou 310027, China)

Abstract: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 Ea; and that the top-temperature of decomposition Tp 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 Ea and Tp to decline sharply with the decrease of the average diameter of nano-particles.
Keywords:Nano-particle, Aggregation, Non-isothermal kinetics, Surface effect, Phase interface reaction.

CLC Number:O614.23;O643.12 Document ID:A

Foundation Item:Project supported by Guizhou Province Natural Science Foundation of China
Author Resume:LI Dai-xi,E-mail: hyshi@tmail.gzu.edu.cn; SHI Hong-yun,dxli75@sohu.com Author for correspondence

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Manuscript Received:2002年10月8日

Manuscript Revised:2002年12月2日

Published:2003年6月1日