Abstract: Thermogravimetric analyzer was used to study the factors influence on calcining decomposition of nanoscale calcium carbonate under pure nitrogen atmosphere，the factors included heating rate， environmental atmosphere，etc. The results were compared with two routine calcium carbonates，meanwhile，the calcining decomposition kinetics of nanoscale calcium carbonate were also analyzed. It was found that the decomposition of nanoscale calcium carbonate was more active than that of routine calcium carbonates，and the decomposition temperature was lower under the same reaction condition. The decomposition reaction moved to the high temperature area with the increase of the heating rate. The partial pressure of CO₂ greatly affected the decomposition of nanoscale calcium carbonate，which resulted in a great delay in its decomposition temperature. The decomposition of nanoscale calcium carbonate is controlled by the mechanism of nucleation and growth（n=1）. The activation energy of nanoscale calcium carbonateis is generally lower than that of the other two routine calcium carbonates.

Key words: nanoscale calcium carbonate, calcination decomposition, dynamic mechanism, heating rate, high concentration CO₂