Toward Understanding the Effect of Water Sorption on Lithium Zirconate (Li2ZrO3) during Its Carbonation Process at Low Temperatures

Lithium metazirconate with and without potassium were synthesized by solid-state reaction. Different water vapor sorption experiments were performed in the presence and absence of CO2 to elucidate the different physicochemical processes produced. In the absence of CO2, initial results showed that potassium addition enhances significantly the water sorption on the Li2ZrO3 ceramic. Then, it was shown that water vapor is trapped by two different mechanisms on Li2ZrO3, adsorption and absorption. When CO2 was added to water vapor flow the Li2ZrO3 reactivity increased significantly. On the basis of these results, a possible K−Li2ZrO3−H2O−CO2 reaction mechanism was proposed; as a first step Li2ZrO3 and H2O must react producing some Li−OH and Zr−OH species. Then, CO2 must react with hydroxyl species (mainly Li−OH), producing lithium carbonate. Finally, the presence of this new specie must favor a higher water adsorption.