Gas-solid carbonation of lime produced by thermal decomposition of dolomite

This work describes the non-isothermal kinetics and mechanism of gas-solid (dry) carbonation of lime obtained by thermal decomposition of dolomite. The course of the process was studied by constant cooling rate derivative thermogravimetric analysis in the flow of carbon dioxide. The activation energy of thermal decomposition during heating of dolomite is lower than that for the process of gas-solid carbonation of lime during cooling. From a thermodynamic point of view, this difference in activation energy is equal to the positive isobaric work. In the mechanism of both processes, diffusion is a rate-determining reaction step. However, the different geometry of the growing nuclei causes a difference in their mechanism.