Ca‐Mg acetate as dry SO2 sorbent: III. Sulfation of MgO+CaO

The separate sulfation rate of MgO contained in calcined calcium magnesium acetate (CMA) by SO2 and O2 was measured, as well as the simultaneous sulfation of MgO and CaO in the temperature range where the sulfates of both oxides are stable. In the temperature range below 830°C in which MgO sulfation is thermodynamically possible the reaction produced CaSO4·3MgSO4, rather than MgSO4. The formation of the CaSO4·3MgSO4 phase at a reasonable rate during the sulfation of calcined CMA has a significant implication in that it allows the utilization of MgO for SO2 removal, whereas the sulfation of MgO from conventional sources is so slow that it is of no practical interest. Thus, the calcined CMA can remove SO2 at lower temperatures than conventional SO2 absorbent and at a greater capacity and rate, which presents a substantial competitive advantage of this material.