Zn2+ as a dopant to stabilize hydrated magnesium carbonates
Nguyen, Hoang; Kamala Ilango, Nirrupama; Winnefeld, Frank; Lothenbach, Barbara; Kinnunen, Paivo (2025-06-12)
Elsevier
12.06.2025
Nguyen, H., Kamala Ilango, N., Winnefeld, F., Lothenbach, B., & Kinnunen, P. (2025). Zn2+ as a dopant to stabilize hydrated magnesium carbonates. Cement and Concrete Research, 197, 107963. https://doi.org/10.1016/j.cemconres.2025.107963
https://creativecommons.org/licenses/by/4.0/
© 2025 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
https://creativecommons.org/licenses/by/4.0/
© 2025 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
https://creativecommons.org/licenses/by/4.0/
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:oulu-202506174674
https://urn.fi/URN:NBN:fi:oulu-202506174674
Tiivistelmä
Abstract
The formation of solid solutions of Mg‑carbonates incorporating Zn2+ was investigated. The presence of Zn retarded the reaction of brucite at the early stages but increased its reaction in the long-term. The initially formed nesquehonite [MgCO3·3H2O] and brucite converted to dypingite [Mg5(CO3)4(OH)2·5H2O] with time, both in the absence and presence of Zn, while dypingite remained stable throughout the duration of the study (1 year). Zinc forms a solid solution with dypingite with a maximum Zn/(Mg + Zn) molar ratio of 0.01. The solid solution was found to be thermodynamically more stable than pure dypingite. With further increase of Zn beyond 0.01 Zn/(Mg + Zn) molar ratios, the excess zinc precipitates as X-ray amorphous phases with a possible Zn/Mg atomic ratio of 2 at early reaction time. The findings reported here confirm the possibility of solid solution formation in HMCs enabling the improved stability of certain HMCs for safe utilization as construction materials.
The formation of solid solutions of Mg‑carbonates incorporating Zn2+ was investigated. The presence of Zn retarded the reaction of brucite at the early stages but increased its reaction in the long-term. The initially formed nesquehonite [MgCO3·3H2O] and brucite converted to dypingite [Mg5(CO3)4(OH)2·5H2O] with time, both in the absence and presence of Zn, while dypingite remained stable throughout the duration of the study (1 year). Zinc forms a solid solution with dypingite with a maximum Zn/(Mg + Zn) molar ratio of 0.01. The solid solution was found to be thermodynamically more stable than pure dypingite. With further increase of Zn beyond 0.01 Zn/(Mg + Zn) molar ratios, the excess zinc precipitates as X-ray amorphous phases with a possible Zn/Mg atomic ratio of 2 at early reaction time. The findings reported here confirm the possibility of solid solution formation in HMCs enabling the improved stability of certain HMCs for safe utilization as construction materials.
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