Thermal Decomposition Process and Kinetics of Micro-fine Magnesite

doi:10.12068/j.issn.1005-3026.2018.03.019

Abstract

Abstract: Thermal decomposition kinetics of highly pure micro-fine magnesite particles was studied by TG-DSC techniques at varying heating rates. The results indicate that with increase of heating rate， decomposition rate of magnesite increases gradually and maximum decomposition rate shifts to the high-temperature zone. Firstly， TG experimental data obtained at different heating rates were calculated with Hu-Gao-Zhang equation， which determined uniqueness and activation energy value of thermal decomposition mechanism function of magnesite. And then double equal-double steps method combined with morphological analysis on calcined products were adopt to determine differential form for most probable mechanism function of thermal decomposition， it is f(α)=2(1-α)^1/2， and the outside-in (i.e. from cleavage surfaces to the interior of crystal) thermal decomposition of particles is a typical phase boundary reaction. Finally the pre-exponential factor was calculated by Flynn-Wall-Ozawa equation， and thermal decomposition kinetics equation of micro-fine magnesite is established. Two sets of TG data with different heating rates were used to verify the established equation and prove it is reasonable equation.

Key words: magnesite, thermal decomposition, kinetics, decomposition mechanism, thermogravimetric analysis

CLC Number:

TQ132.2

BAI Li-mei， DENG Yu-fen， HAN Yue-xin， ZHAO Wen-qing. Thermal Decomposition Process and Kinetics of Micro-fine Magnesite[J]. Journal of Northeastern University Natural Science, 2018, 39(3): 398-403.

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