%0 Journal Article %T In situ kinetic measurements of gas–solid carbonation of Ca(OH)2 by using an infrared microscope coupled to a reaction cell %+ Laboratoire de Planétologie de Grenoble (LPG) %+ Laboratoire de Géodynamique des Chaines Alpines (LGCA) %+ Physikalisches Institut [Bern] %+ Physics of Geological Processes [Oslo] (PGP) %A Montes-Hernandez, G. %A Pommerol, A. %A Renard, F. %A Beck, P. %A Quirico, E. %A Brissaud, O. %< avec comité de lecture %@ 1385-8947 %J Chemical Engineering Journal %I Elsevier %V 161 %P 250-256 %8 2010-07 %D 2010 %Z 10.1016/j.cej.2010.04.041 %R 10.1016/j.cej.2010.04.041 %Z Sciences of the Universe [physics]/Earth Sciences/Geochemistry %Z Environmental Sciences/Global ChangesJournal articles %X Gas–solid carbonation experiments were carried out by using an infrared microscope coupled to a reaction cell. The hydroxide ions (OH) consumption and the production of molecular water (H2O) and carbonate (CO32−) vibration bands were directly monitored as a function of time. Herein, we demonstrated that the gas–solid carbonation of calcium hydroxide (or portlandite) was exclusively activated by initial adsorbed water-molecules (water activity ≈ 0.6 in the lab room) at low temperature (30 °C) and low CO2 pressure (0.5–1.5 bar). We assume that carbonation reaction was then rapidly autocatalysed by the water production and followed by a passivation step due to the formation of a dense layer of carbonate around the reacting particles of portlandite. The fast carbonation and passivation steps were satisfactory fitted by using a kinetic pseudo-second-order model. Moreover, the infrared measurements provided complementary insights with relevance to the reaction mechanism of gas–solid carbonation of calcium hydroxide. Herein, the formation of metastable aragonite was identified and a hydrated calcium carbonate was suspected during carbonation process. On the other hand, when initial adsorbed water onto reacting particles was removed by in situ vacuum drying (P < 10−5 mbar, T = 110 °C) prior to injection of CO2 in the reaction cell (water activity ≈ 0), the carbonation of calcium hydroxide particles was no more detected by infrared spectroscopy at low temperature (30 °C). However, there was evidence for a very limited carbonation reaction at higher temperature (300 °C) and low CO2 pressure (<1 bar). Another carbonation mechanism is required to explain this observation, for example the migration of oxygen atoms from the solid towards adsorbed CO2. %G English %L insu-00549816 %U https://insu.hal.science/insu-00549816 %~ SDE %~ INSU %~ UNIV-SAVOIE %~ UGA %~ CNRS %~ UNIV-GRENOBLE1 %~ INPG %~ IRSTEA %~ OSUG %~ GIP-BE %~ AGREENIUM %~ INRAE %~ USMB-COMUE