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Formation of Fluorapatite in the Equilibrium System CaO–P2O5–HF–H2O at 298 K in a Nitrogen Atmosphere Full article

Journal Crystals
, E-ISSN: 2073-4352
Output data Year: 2023, Volume: 13, Number: 8, Article number : 1264, Pages count : 12 DOI: 10.3390/cryst13081264
Tags fluorapatite; formation; water system; low concentration; equilibrium; isotherm
Authors Chaikina Marina V. 1 , Bulina Natalia V. 1 , Prosanov Igor Yu. 1 , Ishchenko Arcady V. 2
Affiliations
1 Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of Russian Academy of Sciences, Kutateladze 18, Novosibirsk 630090, Russia
2 G.K. Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Pr. Akad. Lavrentieva 5, Novosibirsk 630090, Russia

Funding (1)

1 Ministry of Science and Higher Education of the Russian Federation 075-00521-21-00 (121032500064-8) (FWUS-2021-0009)

Abstract: The process of biomineralization of apatite in nature has been studied by scientists from various fields of science for more than a century. Unlike the volcanogenic, hydrothermal, and other types of igneous apatites, the genesis of which is entirely clear, the formation of phosphate ores of marine sedimentary origin is still debatable. Since phosphate concentrations in water bodies are too low for the spontaneous precipitation of solid phosphates, the study of different ways for their concentration is of particular interest. In this work, phase equilibria in the system CaO–P2O5–HF–H2O at 298 K, involving fluorapatite formation, have been studied. Fluorapatite is known to be the most common phosphate mineral and the main source of phosphorus on Earth, playing an important role in the mineralization process of dental tissues in vertebrates. The equilibrium in the system defined above was studied at a low mass fraction of the liquid phase components, i.e., in conditions close to natural. It has been shown that the compounds of variable composition with the fluorapatite structure containing HPO42− ions were formed in the acid region of this system. These compounds are formed at pH ≤ 7.0 and have invariant points with monetite, CaHPO4, and fluorite, CaF2. Stoichiometric fluorapatite was formed at the lowest concentrations of the liquid phase components in a neutral and weakly alkaline medium and had an invariant point with Ca(OH)2. The composition of the resulting equilibrium solid phases was found to be dependent on the Ca/P ratio of the initial components and pH of the equilibrium liquid phase. Fluorite CaF2 was present in each sample obtained in this study.
Cite: Chaikina M.V. , Bulina N.V. , Prosanov I.Y. , Ishchenko A.V.
Formation of Fluorapatite in the Equilibrium System CaO–P2O5–HF–H2O at 298 K in a Nitrogen Atmosphere
Crystals. 2023. V.13. N8. 1264 :1-12. DOI: 10.3390/cryst13081264 WOS Scopus РИНЦ ANCAN OpenAlex
Dates:
Submitted: Jul 10, 2023
Accepted: Aug 12, 2023
Published print: Aug 16, 2023
Published online: Aug 16, 2023
Identifiers:
Web of science: WOS:001056434500001
Scopus: 2-s2.0-85169168998
Elibrary: 54907784
Chemical Abstracts: 2023:1822995
Chemical Abstracts (print): 185:16678
OpenAlex: W4385878046
Citing:
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Scopus 2
OpenAlex 2
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