Final pH decrease: the growing magnesium hydroxide forms a layer, which impedes the diffusion of water into the pores. Hydroxylation ceases, and precipitation continues until the rema- ining supersaturation is removed. Moreover, the uptake of CO2 supports the pH decrease and has to be taken into account when CO2 intrusion is not avoided.
SEM images of the MgO particles (Fig. 3) and the reference
materials Mg(OH)2, MgO and calcined MgO show round, porous