文摘
The simultaneous adsorption kinetic parameters of synthetic gyrolite (200 °C, 48 h) for heavy metals ions (zinc, copper, manganese, nickel, iron and cobalt ions) as well as the influence of this compound on the hydration of ordinary Portland cement were studied. The examination revealed that the intercalation of heavy metal ions into the crystal structure of gyrolite proceeds intensively at the beginning of the process, because after 30 s the amount of adsorbed ions reaches 93 %. It was estimated that the reactions of simultaneous adsorption are not reversible, i.e., almost all heavy metal ions are chemisorbed by gyrolite. The experimental data were adequately described by pseudo-second Ho kinetic model: The largest adsorption rate constant is typical for iron ions (1.65 g min−1 mg−1), while the minimum value—for cobalt ions (0.45 g min−1 mg−1). It was found that gyrolite with impure heavy metal ions retained very good adsorption properties for the alkaline and alkaline earth ions by accelerating the early hydration of ordinary Portland cement samples. Meanwhile, at later stages of hydration, this compound affects as the usual pozzolanic additives because the amount of cumulative heat grew with the increasing amount of gyrolite in the samples: from 282 J g−1 in pure ordinary Portland cement samples to 301 J g−1 in samples with 15 % of gyrolite with impure heavy metal ions. It was determined that the additive of gyrolite with impure heavy metal ions do not have a significant effect on the properties of cement stone.
