carbonation of portlandite (Ca(OH)2) proceeds as outlined in
eq 1. Therefore, for every 1 g of Ca(OH)2 that carbonates, 1.35
g of CaCO3 are produced. Although the start and end states are
well-defined, i.e., when carbonation is complete, the rate at
which the reaction proceeds is a function of parameters,
including temperature, pressure, and the presence of water.2
Moreover, depending on the presence of liquid water, i.e.,
whether carbonation is dissolution−precipitation mediated or
not (rather than simply facilitated by the presence of adsorbed
water), metastable products, such as amorphous calcium
carbonate (ACC), or the other CaCO3 polymorphs (i.e.,
vaterite or aragonite) may form before their subsequent
conversion to calcite, which is often noted as the stable endstate
product.47−49