Dehydration of sodium carbonate monohydrate

Physico-geometrical kinetics of the thermal dehydration of sodium carbonate monohydrate as a compacted composite of inorganic hydrate comprising crystalline particles and matrix

“…Scanning electron microscopy (SEM) images of the SC-MH reagent reported in previous works revealed a specific surface texture characterized by many columnar crystals several μm in length attached on and sticking out from relatively smooth grain surface. 37,38 Also, researchers confirmed that the powder X-ray diffraction (XRD) pattern of the SC-MH reagent exactly corresponds to that of Na 2 CO 3 ·H 2 O (thermonatrite) and that the mass loss owing to thermal dehydration is coincident with the calculated value for the thermal dehydration of SC-MH, which forms anhydride. 37 Na 2 CO 3 ·H 2 O(s) → Na 2 CO 3 (s) + H 2 O(g)However, in our preliminary study, a derivative mass loss curve of the thermal dehydration with a specific shape, exhibiting a shoulder before the main peak, was observed, possibly indicating a multistep mass loss process.…”

“…37,38 Also, researchers confirmed that the powder X-ray diffraction (XRD) pattern of the SC-MH reagent exactly corresponds to that of Na 2 CO 3 ·H 2 O (thermonatrite) and that the mass loss owing to thermal dehydration is coincident with the calculated value for the thermal dehydration of SC-MH, which forms anhydride. 37 Na 2 CO 3 ·H 2 O(s) → Na 2 CO 3 (s) + H 2 O(g)However, in our preliminary study, a derivative mass loss curve of the thermal dehydration with a specific shape, exhibiting a shoulder before the main peak, was observed, possibly indicating a multistep mass loss process. This differs from the smooth derivative mass loss curve observed for the thermal dehydration of SC-MH fine powder samples produced by the efflorescence of Na 2 CO 3 ·10H 2 O (SC-DH) crystals.…”

Crystallographic and Morphological Transformation of Natrite and Nahcolite in the Dry Carbonate Process for CO2Capture

“…For the carbonation tests of the second type (3.1.2), as with the phases obtained in the experiments of the first type (3.1.1), to our knowledge no calculations of coherent crystal length sizes have been reported previously by PXRD. In addition to the SEM micrographs of the works discussed for the experiments of the first type (3.1.1) reported in the literature, additional works have also been reported for thermonatrite under N 2 at constant water-vapor pressure, or in ethylene glycol solution. , In the paper by Oosterhof, a Coulter multisizer was used to measure the particle size distribution of the thermonatrite obtained . The particle sizes obtained for the temperatures of 50, 60, and 70 °C were compared, observing that, for 70 °C, slightly higher particle sizes were obtained than in the other cases.…”

“…30 Another mechanism of formation is the one that has been observed in this work, from the exposure of natrite to humidity. 46 Dehydration of thermonatrite has been previously studied, 47 it being one of the industrial production methods of natrite. 46,48 The presence of trona at the same temperatures and of natrite at 60 °C has already been observed in our first type of carbonation experiments (3.1.1).…”

Multistep Kinetic Behavior of the Thermal Decomposition of Granular Sodium Percarbonate: Hindrance Effect of the Outer Surface Layer

“…The outer surface layer of SPC granules increases the structural strength of the granules and protects the internal SPC crystalline particles from the deterioration via the action of atmospheric water vapor. In addition to this physical shielding effect, the outer surface layer also chemically absorbs atmospheric water vapor via the reaction: , …”