Catalytic Action of Atmospheric Water Vapor on the Thermal Decomposition of Synthetic Hydrozincite

抄録

The effect of atmospheric water vapor on the kinetic rate behavior of the thermal decomposition of zinc carbonate hydroxide, Zn₅(CO₃)₂(OH)₆, was investigated by means of TG-DTA under the controlled partial pressure of atmospheric water vapor, p(H₂O). With increasing p(H₂O) from 0.7 to 9.4 kPa, the reaction temperature at the restricted heating rate was reduced systematically accompanied by the change in the shape of TG curves. Through systematic kinetic analysis of the reaction at different p(H₂O), the change in the kinetic behavior was characterized by the mutually dependent decreases in the apparent activation energy and the Arrhenius pre-exponential factor, where the catalytic action of atmospheric water vapor on the surface nucleation process was identified as the possible mechanistic origin.