Abstract—The solubility of fluorite in HCl and HF solutions with a variable concentration of Zr at 90, 155, 205, and 255°C and the pressure of saturated water vapor is investigated. It is shown that the solubility of fluorite increases with zirconium concentration. The free energies of the \({\text{ZrF}}_{6}^{{2 - }}\) complex determined from the experimental data using OptimA software were used to calculate the dissociation constants of the \({\text{ZrF}}_{6}^{{2 - }}\) = Zr4+ + 6F– reaction. The pK values were 29.86 ± 0.13, 34.03 ± 0.062, 38.28 ± 0.033, 40.94 ± 0.079 at 90, 155, 205, and 255°C (saturated water vapor pressure).
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Funding
The experiments were carried out with the support of the Russian Foundation for Basic Research (project no. 18-35-00075), thermodynamic calculations with the support of the Russian Science Foundation (project no. 19-17-00200).
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Tarnopolskaia, M.E., Bychkov, A.Y. An Experimental Study of \({\text{ZrF}}_{6}^{{2 - }}\) Stability in Hydrothermal Solutions at 90–255°C. Moscow Univ. Geol. Bull. 75, 105–109 (2020). https://doi.org/10.3103/S0145875220010147
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DOI: https://doi.org/10.3103/S0145875220010147