Experimental study of fluorite solubility in acidic solutions as a method for boron fluoride complexes studying
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Fluorite solubility in HCl and HF solutions with varied concentrations of boric acid was studied at 81, 155, and 208°C and saturated vapor pressure. Our experimental results demonstrate that fluorite solubility increases with increasing B(OH)3 concentration, and this was interpreted as the formation of the BF3OH–complex (Ryss, 1956). The experimental data were used to determine, using the OptimA software, the free energies of formation of HF°(aq) and, which were then used to calculate the constants of the reactions HF = H+ + F– (1) and B(OH)3(aq) + 2H+ + 3 F– (2). The pK 1 values are 3.71 ± 0.013, 4.28 ± 0.015, and 4.89 ± 0.017 and pK 2 13.60 ± 0.02, 13.99 ± 0.02, and 14.95 ± 0.03 at saturated vapor pressure and 81, 155, and 208°C, respectively.
Keywordshydrothermal solutions transport species of elements fluoride complexes fluorite boron
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- M. V. Borisov and Yu. V. Shvarov, Thermodynamics of Geochemical Processes (Mosk. Gos. Univ., Moscow, 1992) [in Russian].Google Scholar
- O. V. Bryzgalin and R. P. Rafal’skii, “Approximate estimation of instability constants of complexes of ore elements at elevated temperatures,” Geokhimiya, No. 6, 839–349 (1982).Google Scholar
- A. J. Ellis, “The effect of temperature on the ionization of hydrofluoric acid,” J. Chem. Soc. 4300–4304 (1963).Google Scholar
- J. C. Holland and S. D. Malinin, The Solubility and Occurrence of Non-Ore Minerals, in Geochemistry of Hydrothermal Ore Deposits, Ed. by H. L. Barnes (Wiley, New York, 1979), pp. 461–508.Google Scholar
- V. Yu. Prokof’ev, I. S. Peretyazhko, S. Z. Smirnov, B. R. Tagirov, E. O. Groznova, and E. A. Samsonova, Boron and Boric Acid in Endogenous Ore-Forming Processes (PAS’VA, Moscow, 2003) [in Russian].Google Scholar
- I. G. Ryss, Chemistry of Chlorine and its Inorganic Compounds (Goskhimizdat, Moscow, 1956) [in Russian].Google Scholar
- B. N. Ryzhenko, “Major tendencies and relations in the thermodynamics of electrostatic dissociation in hightemperature aqueous solutions,” Geokhimiya, No. 8, 1123 (1974).Google Scholar
- E. L. Shock, E. H. Oelkers, J. W. Johnson, D. A. Sverjensky, and H. C. Helgeson, “Calculation of the thermodynamic properties of aqueous species at high pressures and temperatures: effective electrostatic radii, dissociation constants and standard partial molal properties to 1000°C and 5 kbar,” J. Chem. Soc. Faraday Trans. 88, 803–826 (1992).CrossRefGoogle Scholar
- M. E. Tarnopolskaia, and A. Yu. Bychkov, “Experimental study of stability of fluoride complexes of gallium at 89–250°C and saturated water vapor pressure,” Eksperim. Geokhim. 2 (3), 352–356 (2014).Google Scholar