Thermally induced carbonation of Ca(OH)₂ in a CO₂ atmosphere: kinetic simulation of overlapping mass-loss and mass-gain processes in a solid–gas system

Abstract

Thermally induced carbonation of Ca(OH)2 in a CO2 atmosphere is a reaction exhibiting particular features, including stoichiometric completeness to form CaCO3 and a kinetic advantage over the carbonation of CaO particles.

ICTAC Kinetics Committee recommendations for analysis of multi-step kinetics

“…When the chemical reaction in each reaction step and a relationship between the steps has been revealed by the supplementary techniques, the individual reactions making opposing contributions (i.e, mass loss versus mass gain or exothermic versus endothermic) to the overall rate process can also be analyzed by KDA. This has been recently demonstrated for the thermal decomposition and subsequent oxidation or carbonation processes [153,154,155].…”

“…KDA is applicable to kinetic data recorded under any temperature programs [150,151,152,153] as shown in Figure 5.2 for the two-step thermal decomposition of Mg(OH)2 under linear nonisothermal, isothermal, and constant transformation rate conditions [152]. When the contributions and kinetic parameters of each reaction step are invariant with respect to different temperature programs, the kinetic curves measured under different conditions can be simultaneously subjected to KDA.…”

Critical Appraisal of Kinetic Calculation Methods Applied to Overlapping Multistep Reactions

“…In some cases, the respective reaction steps can bring the opposite contributions to the overall process as measured using a TA technique. Experimental studies concerning the overall reaction composed of more than one reaction step with oppositely signed TA signals have been reported, i.e., partially overlapping mass loss and mass gain [3,28,29], or exothermic and endothermic events [30,31,32]. In practice, such complex processes are observed during thermal decomposition of energetic materials [5] and high-temperature operations with ionic liquids [33].…”

New insights into the mechanisms of carbon dioxide mineralization by portlandite

“…At one end, the carbonation of conventional portland cement concrete is a deleterious process that occurs over years as concrete interacts with atmospheric CO 2 43 . In other cases, the carbonation of lime/hydrated lime particulates has been examined in the context of cyclic carbon capture applications, for example, calcium looping 44‐48 . This study examines a processing regime that has received far less attention—that is, subboiling temperatures, super‐ambient CO 2 concentrations, and effectively, atmospheric pressure.…”