Influences of evolved gases on the thermal decomposition of zinc carbonate hydroxide evaluated by controlled rate evolved gas analysis coupled With TG

The influences of atmospheric CO2 and H2O on the kinetics of the thermal decomposition of zinc carbonate hydroxide, Zn-5(CO3)(2)(OH)(6), were investigated by means of controlled rate evolved gas analysis (CREGA) coupled with TG. Although CO2 and H2O were evolved simultaneously in a single mass-loss step of the thermal decomposition, different effects of those evolved gases on the kinetic rate behavior were observed. No distinguished effect of atmospheric CO2 was detected within the possible range of self-generated CO2 concentration. On the other hand, apparent acceleration effect by the increase in the concentration of atmospheric H2O was observed as the reduction of reaction temperature during the course of constant rate thermal decomposition. The catalytic effect was characterized by the decrease in the apparent activation energy for the established reaction with increasing the concentration of atmospheric H2O, accompanied by the partially compensating decrease in the pre-exponential factor.