Change in Surface Property of Calcium Carbonate by Heat-treatment

FUJI Masayoshi, ZHANE Jingping, TAKEI Takashi, WATANABE Tohoru, CHIKAZAWA Masatoshi, WATANABE Tatsuhiko, TANABE Katsuyuki

doi:10.11451/mukimate1994.4.330

The surface properties of heavy and colloidal calcium carbonate heat-treated under flowing nitrogen were examined from SEM, XRD, IR, specific surface area measurements and desorbed gas analysis by using modified temperature programmed desorption method. As a result, it was suggested that the structure of heavy calcium carbonate surface was almost as same as bulk. The physisorbed water molecules on the surface were desorbed over the range of room temperature to 200°C. The remarkable surface pyrolysis of calcium carbonate occurred with degassed carbon dioxide at 500°C. On the other hand, the surface component of colloidal calcium carbonate was similar to calcium hydroxide in several surface layers. The physisorption water molecules were desorbed until 250°C. The thermal decomposition of calcium carbonate under the layer of calcium hydroxide was slightly observed at above 500°C. It was concluded that the difference of surface properties between heavy and colloidal calcium carbonate, such as desorption temperature of physisorbed water, and surface thermal decomposition mechanism, was affected by a difference of surface initial condition.

Change in Surface Property of Calcium Carbonate by Heat-treatment

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