Investigating the optimum conditions for the formation of calcium oxide, used for CO2 sequestration, by thermal decomposition of calcium acetate

Abstract

Calcium oxide, CaO, has long been recognized as an effective, regenerative sorbent for the sequestration of CO2. Calcium acetate hydrate, CaAc, (Ca(CH3COO)2·xH2O) has been highlighted as one of the most efficient precursors for CaO production with regards to CO2 sequestration. In this study, thermal decomposition of CaAc to CaO, via an intermediate phase of calcium carbonate (CaCO3), has been examined at different heating rates using thermal and powder diffraction analysis. The decomposition from CaAc to CaO has yet to be analysed in detail at the particulate level, however, knowledge of how the transformation proceeds at this level should lead to control over the size and morphology of the final CaO product. Bulk characterisation using X-ray diffraction (XRD) and thermogravimetric analysis (TGA) has been used to benchmark the transformation at different heating rates and final calcination temperatures. TEM imaging is used to show how the chemical changes proceed particularly at the particle level.