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摘要
AlOOH coated calcium carbonate was synthesized by a two-step chemical solution reaction. The phase and microstructure analysis were carried out by X-ray diffraction and scanning electron microscopy. Nonisothermal decomposition kinetics of the AIOOH coated calcium carbonate has been investigated on the basis of the TG-DTA analysis. The model-free and model fitting approaches were applied to the data for non-isothermal decomposition kinetics of AlOOH surface-coated calcium carbonate as well as the reference. Master-plot method was used to determine the decomposition mechanisms based on the kinetic parameter E(a) achieved by model-free Kissinger equation. The reference sample decomposed according to the contracting area mechanism R(2) and the AlOOH surface-coated calcium carbonate decomposed The kinetic parameters E(a) verified by both integral method to one-dimensional mechanism D(1) and differential method showed about 90 kJ mol(-1) increase in the decomposition process after being coated. This is possibly due to the as-shell structure of surface AlOOH, which hinders the diffusion of the dissociated CO(2) into the outer atmosphere.
