Cargando…
Heat-Induced Dolomitization of Amorphous Calcium Magnesium Carbonate in a CO(2)-Filled Closed System
[Image: see text] We report a method to synthesize dolomite [CaMg(CO(3))(2)] from amorphous calcium magnesium carbonate (ACMC) via solid-state transformation. When ACMC is heated in air, it does not crystallize into dolomite but decomposes into Mg calcite, magnesium oxide, and CO(2). Hence, we heate...
Autores principales: | , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2022
|
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9753508/ https://www.ncbi.nlm.nih.gov/pubmed/36530237 http://dx.doi.org/10.1021/acsomega.2c03258 |
_version_ | 1784850978601697280 |
---|---|
author | Sugawara, Shingo Fujiya, Wataru Kagi, Hiroyuki Yamaguchi, Akira Hashizume, Ko |
author_facet | Sugawara, Shingo Fujiya, Wataru Kagi, Hiroyuki Yamaguchi, Akira Hashizume, Ko |
author_sort | Sugawara, Shingo |
collection | PubMed |
description | [Image: see text] We report a method to synthesize dolomite [CaMg(CO(3))(2)] from amorphous calcium magnesium carbonate (ACMC) via solid-state transformation. When ACMC is heated in air, it does not crystallize into dolomite but decomposes into Mg calcite, magnesium oxide, and CO(2). Hence, we heated ACMC in a closed system filled with CO(2) gas (pCO(2) >1.2 bar at 420 °C) and produced submicron-sized dolomite. Single-phase dolomite was obtained after dissolving impurities in the run products, such as northupite [Na(3)Mg(CO(3))(2)Cl] and eitelite [Na(2)Mg(CO(3))(2)], in water. Also, we investigated the crystallization process of dolomite by changing the heating temperature and heating time. Despite crystallization by solid-state transformation, the heated samples crystallized to dolomite via Ca-rich protodolomite with no ordering reflection of X-ray diffraction as previously observed for hydrothermal synthesis. The results demonstrated that this crystallization pathway is kinetically favored even in solid-state transformation and that the Ca-rich protodolomite phase preferentially crystallizes during heating, leading to phase separation from the amorphous phase. Therefore, the crystallization process via protodolomite as a precursor is a common mechanism in dolomite crystallization, suggesting the presence of kinetic barriers other than hydration of cations. |
format | Online Article Text |
id | pubmed-9753508 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-97535082022-12-16 Heat-Induced Dolomitization of Amorphous Calcium Magnesium Carbonate in a CO(2)-Filled Closed System Sugawara, Shingo Fujiya, Wataru Kagi, Hiroyuki Yamaguchi, Akira Hashizume, Ko ACS Omega [Image: see text] We report a method to synthesize dolomite [CaMg(CO(3))(2)] from amorphous calcium magnesium carbonate (ACMC) via solid-state transformation. When ACMC is heated in air, it does not crystallize into dolomite but decomposes into Mg calcite, magnesium oxide, and CO(2). Hence, we heated ACMC in a closed system filled with CO(2) gas (pCO(2) >1.2 bar at 420 °C) and produced submicron-sized dolomite. Single-phase dolomite was obtained after dissolving impurities in the run products, such as northupite [Na(3)Mg(CO(3))(2)Cl] and eitelite [Na(2)Mg(CO(3))(2)], in water. Also, we investigated the crystallization process of dolomite by changing the heating temperature and heating time. Despite crystallization by solid-state transformation, the heated samples crystallized to dolomite via Ca-rich protodolomite with no ordering reflection of X-ray diffraction as previously observed for hydrothermal synthesis. The results demonstrated that this crystallization pathway is kinetically favored even in solid-state transformation and that the Ca-rich protodolomite phase preferentially crystallizes during heating, leading to phase separation from the amorphous phase. Therefore, the crystallization process via protodolomite as a precursor is a common mechanism in dolomite crystallization, suggesting the presence of kinetic barriers other than hydration of cations. American Chemical Society 2022-11-28 /pmc/articles/PMC9753508/ /pubmed/36530237 http://dx.doi.org/10.1021/acsomega.2c03258 Text en © 2022 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Sugawara, Shingo Fujiya, Wataru Kagi, Hiroyuki Yamaguchi, Akira Hashizume, Ko Heat-Induced Dolomitization of Amorphous Calcium Magnesium Carbonate in a CO(2)-Filled Closed System |
title | Heat-Induced Dolomitization
of Amorphous Calcium Magnesium
Carbonate in a CO(2)-Filled Closed System |
title_full | Heat-Induced Dolomitization
of Amorphous Calcium Magnesium
Carbonate in a CO(2)-Filled Closed System |
title_fullStr | Heat-Induced Dolomitization
of Amorphous Calcium Magnesium
Carbonate in a CO(2)-Filled Closed System |
title_full_unstemmed | Heat-Induced Dolomitization
of Amorphous Calcium Magnesium
Carbonate in a CO(2)-Filled Closed System |
title_short | Heat-Induced Dolomitization
of Amorphous Calcium Magnesium
Carbonate in a CO(2)-Filled Closed System |
title_sort | heat-induced dolomitization
of amorphous calcium magnesium
carbonate in a co(2)-filled closed system |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9753508/ https://www.ncbi.nlm.nih.gov/pubmed/36530237 http://dx.doi.org/10.1021/acsomega.2c03258 |
work_keys_str_mv | AT sugawarashingo heatinduceddolomitizationofamorphouscalciummagnesiumcarbonateinaco2filledclosedsystem AT fujiyawataru heatinduceddolomitizationofamorphouscalciummagnesiumcarbonateinaco2filledclosedsystem AT kagihiroyuki heatinduceddolomitizationofamorphouscalciummagnesiumcarbonateinaco2filledclosedsystem AT yamaguchiakira heatinduceddolomitizationofamorphouscalciummagnesiumcarbonateinaco2filledclosedsystem AT hashizumeko heatinduceddolomitizationofamorphouscalciummagnesiumcarbonateinaco2filledclosedsystem |