Abstract
The thermodynamic properties of Na2O-SiO2 solid (942-1285 K) and liquid (1103-1719 K, 19.5-61.8 mol % Na2O) silicates were studied by Knudsen cell mass spectrometry. To determine the activities of the constituent oxides, these were reduced to volatile suboxides directly in effusion cells. Mass spectra of the saturated vapor over Na2O-SiO2 showed the presence of the Na+, Na2O+, NaO+, O +2 , TaO+, TaO +2 , NbO+, NbO2, MoO+, MoO +2 , MoO +3 , and NiO+ ions resulting from the ionization of the Na, Na2O, NaO, NaO2,O2, TaO, TaO2, NbO, NbO2, MoO, MoO2, MoO3, and NiO molecules. The activities calculated by two different procedures were found to coincide within the experimental error. The enthalpies and Gibbs energies of formation of sodium silicates were shown to be extremely low. The formation of solid orthoand metasilicates is accompanied by a decrease in entropy, in contrast to the other sodium silicates. Sodium orthosilicate has the lowest enthalpy and Gibbs energy. A thermodynamic model for Na2O-SiO2 melts is proposed which relies on associated solution theory and takes into account silica polymerization. The model describes the composition and temperature dependences of the activities of the constituent oxides in the melt with an accuracy no worse than the experimental error (2-3%). The model, in combination with the thermodynamic functions of formation of all the intermediate solid phases, was used to calculate phase equilibria in the Na2O-SiO2 system. The results agree well with the experimental data obtained by physicochemical methods.
References
Zaitsev, A.I. and Mogutnov, B.M., Thermodynamic Properties and Phase Equilibria in the MnO-SiO2 System,J. Mater. Chem., 1995, vol. 5, pp. 1063–1073.
Zaitsev, A.I., Litvina, A.D., and Mogutnov, B.M., Thermodynamic Properties of Ca2-SiO2-CaO Melts,Neorg. Mater., 1997, vol. 33, no. 1, pp. 76–86 [Inorg. Mater. (Engl. Transl.), vol. 33, no. 1, pp. 68–77].
Zaitsev, A.I., Litvina, A.D., and Mogutnov, B.M., Thermodynamic Properties and Phase Equilibria in the CaF2-SiO2-Al2O3-CaO System: I. Experimental Study of CaF2-SiO2-Al2O3-CaO Melts,Neorg. Mater., 1997, vol. 33, no. 12, pp. 1489–1498 [Inorg. Mater. (Engl. Transi.), vol. 33, no. 12, pp. 1265-1273].
Zaitsev, A.I. and Mogutnov, B.M., Thermodynamics of CaO-SiO2 and MnO-SiO2 Melts: I. Experimental Study,Neorg. Mater., 1997, vol. 33, no. 7, pp. 839–847 [Inorg. Mater. (Engl. Transi.), vol. 33, no. 7, pp. 707–714].
Zaitsev, A.I., Litvina, A.D., Lyakishev, N.P., and Mogutnov, B.M., Thermodynamics of CaO-Al2O3-SiO2 and CaF2-CaO-Al2O3-SiO2 Melts,J. Chem. Soc., Faraday Trans., 1997, vol. 93, no. 17, pp. 3089–3098.
Zaitsev, A.I. and Mogutnov, B.M., A General Approach to Thermodynamics of High-Temperature Liquid Solutions,High Temp. Mater. Sci., 1995, vol. 34, nos. 1-3, pp. 155–171.
Gurvich, L.V., IVTANTERMO: An Automated Database of the Thermodynamic Properties of Substances,Vestn. Akad. Nauk SSSR, 1983, no. 3, pp. 54–65.
Zaitsev, A.I., Korolyov, N.V., and Mogutnov, B.M., The Vapor Pressures and the Heats of Sublimation of CaF2 and SrF2,High Temp. Sci., 1990, vol. 28, pp. 341–350.
Zaitsev, A.I., Korolev, N.V., and Mogutnov, B.M., Vapor Pressures of CaF2 and SrF2,Teplofiz. Vys. Temp., 1989, vol. 27, no. 3, pp. 465–471.
Hildenbrand, D.L. and Murad, E.,J. Chem. Phys., 1970, vol. 53, p. 3403.
Lamoreaux, R.H. and Hildenbrand, D.L.,J. Phys. Chem. Ref. Data, 1984, vol. 13, p. 151.
Steinberg, M. and Schofield, K., A Reevaluation of the Vaporization Behavior of Sodium Oxide and the Bond Strengths of NaO and Na2O: Implications for the Mass Spectrometric Analyses of Alkali/Oxygen Systems,J. Chem. Phys., 1991, vol. 94, no. 5, pp. 3901–3907.
Kracek, F.C., The System Sodium Oxide-Silica,J. Phys. Chem., 1930, vol. 34, pp. 1583–1598.
Kracek, F.C., Phase Equilibrium Relations in the System Na2SiO3-Li2SiO3-SiO2,J. Am. Chem. Soc., 1939, vol. 61, pp. 2863–2877.
D’Ans, J. and Loeffler, J., Untersuchungen im System Na2O-SiO2-ZrO2,Z. Anorg. Allg. Chem., 1930, vol. 191, pp. 1–34.
Loeffler, J., Über den alkalischen Teil des System Na2O-SiO2,Glastech. Ber., 1969, vol. 42, no. 3, pp. 92–96.
Williamsom, J. and Glasser, F.P., Phase Relations in the System Na2Si2O5-SiO2,Science (Washington, D.C., 1883-), 1965, vol. 148, no. 6, pp. 1589–1591.
Wu, P., Eriksson, G., and Pelton, A.D., Optimization of the Thermodynamic Properties and Phase Diagrams of the Na2O-SiO2 and K2O-SiO2 Systems,J. Am. Ceram. Soc., 1993, vol. 76, no. 3, pp. 2059–2064.
Budnikov, P.P. and Matveev, M.A., Synthesis and Properties of Crystalline Na2O · 3SiO2,Dokl. Akad. Nauk SSSR, 1956, vol. 107, pp. 547–550.
Berman, R.G. and Brown, H.T., The Heat Capacity of Minerals in the System Na2O-K2O-CaO-MgO-FeO-Fe2O3-Al2O3-SiO2-TiO2-H2O-CO: Representation, Estimation, and High Temperature Extrapolation,Contrib. Mineral. Petrol., 1985, vol. 89, pp. 168–183.
Berman, R.G. and Brown, H.T., Erratum Heat Capacity of Minerals in the System Na2O-K2O-CaO-MgO-FeO-Fe2O3-Al2O3-SiO2-TiO2-H2O-CO: Representation, Estimation, and High Temperature Extrapolation,Contrib. Mineral. Petrol., 1986, vol. 94, p. 262.
Knacke, O., Kubaschewski, O., and Hesselmann, K.,Thermochemical Properties of Inorganic Substances, Berlin: Springer, 1991, 2nd ed.
Hillert, M., Sundman, B., and Wang, X., Assessment of the CaO-SiO2 System,Metall. Trans. B, 1990, vol. 21, pp. 303–312.
Shakhmatkin, B.A. and Shul’ts, M.M., Thermodynamic Properties of Na2O-SiO2 Glass-Forming Melts in the Range 800-1200°C,Fiz, Khim. Stekla, 1980, vol. 6, no. 2, pp. 129–135.
Frohberg, M.G., Caung, E., and Kapoor, M.L., Measurement of the Activity of the Oxygen Ions in the Liquid Systems Na2O-SiO2 and K2O-SiO2,Arch. Eisenhuttenwes., 1973, vol. 44, no. 8, pp. 585–588.
Kohsaka, S., Sato, S., and Yokokawa, T.E., Measurements of Molten Oxide Mixtures: III. Sodium Oxide + Silicon Dioxide,J. Chem. Thermodyn., 1979, vol. 11, pp. 547–551.
Yamaguchi, S., Imai, A., and Goto, K.S., Activity Measurement of Na2O in Na2O-SiO2 Melts Using the Beta-Alumina as the Solid Electrolyte,Scand. J. Metall., 1982, vol. 11, pp. 263–264.
Ravaine, D., Azandegbe, E., and Souquet, J.L., Mesures potentiométriques de chaines éléctrochimiques comprenant des silicates fondus: Interprétation des resultats par un modèle statistique,Silic. Ind., 1975, vol. 12, pp. 333–340.
Neudorf, D.A. and Elliott, J.F., Thermodynamic Properties of Na2O-SiO2-CaO Melts at 1100 to 1200°C,Metall. Trans. B, 1980, vol. 11, pp. 607–614.
Goto, K.S., Yamaguchi, S., and Nagata, K., The Chemical Activity of Component Oxides in Na2O-Based Slags,Proc. of 2nd Int. Symp. on Metallurgical Slags and Fluxes, Lake Tahoe, 1984, pp. 467–481.
Pearce, M.L., Calculation of Oxygen Ion Activities in Sodium Silicate and Sodium Borate Melts,J. Am. Ceram. Soc., 1965, vol. 48, pp. 611–613.
Pearce, M.L., Solubility of Carbon Dioxide and Variation of Oxygen Ion Activity in Soda-Silica Melts,J. Am. Ceram. Soc., 1964, vol. 47, no. 7, pp. 342–347.
Rego, D.N., Sigworth, G.K., and Philbrook, W.O., Thermodynamic Study of Na2O-SiO2 Melts at 1300 and 1400°C,Metall. Trans. B, 1985, vol. 16, pp. 313–323.
Tsukihashi, F. and Sano, N., Measurement of the Activity of Na2O in Na2O-SiO2 Melts by Chemical Equilibration Method,Tetsu to Hagane, 1985, vol. 71, no. 7, pp. 815–822.
Holmquist, S., Oxygen Ion Activity and the Solubility of Sulfur Trioxide in Sodium Silicate Melts,J. Am. Ceram. Soc., 1966, vol. 49, no. 9, pp. 467–473.
Shul’ts, M.M., Stolyarova, V.I., and Ivanov, G.G., Mass Spectrometric Study of the Thermodynamic Properties of Na2O-SiO2 Melts and Glasses,Fiz. Khim. Stekla, 1987, vol. 13, no. 2, pp. 168–172.
Chastel, R., Bergman, C., Rogez, J., and Mathieu, J.C., Excess Thermodynamic Functions in Ternary Na2O-K2O-SiO2 Melts by Knudsen Cell Mass Spectrometry,Chem. Geol., 1987, vol. 62, pp. 19–29.
Piacente, V. and Matousek, J., Mass Spectrometric Determination of Sodium Partial Pressure over the System Na2O-2SiO2,Silicates, 1973, vol. 4, pp. 269–280.
Rudnyi, E.B., Vovk, O.M., Sidorov, L.N.,et al., Activity of the Alkali Oxide in Soda-Silica Melts by the Ionic-Molecular Equilibrium Method,Fiz. Khim. Stekla, 1988, vol. 14, no. 2, pp. 218–225.
Yamaguchi, S. and Goto, K.S., Activity Measurement on Na2O in Na2O-SiO2-P2O5 Melts at 900-1400°C Using Beta-Alumina Electrolyte,Scand. J. Metall, 1984, vol. 13, pp. 129–136.
Sokol’skii, V.E., Kazimirov, V.P., and Galinich, V.I., X-ray Diffraction Study of MnO-SiO2 Melts,Izv. Akad. Nauk SSSR, Neorg. Mater., 1983, vol. 19, no. 4, pp. 629–633.
Sokol’skii, V.E., Galinich, V.I., Kazamirov, V.P.,et al., Structure of MnO-TiO2-SiO2 and MnO-ZrO2-SiO2 Melts,Rasplavy, 1987, vol. 1, no. 6, pp. 34–40.
Masson, C.R., An Approach to the Problem of Ionic Distribution in Liquid Silicates,Proc. R. Soc. London, A, 1965, vol. 287, no. 1409, pp. 201–221.
Masson, C.R., Smith, I.B., and Whiteway, S.G., Activities and Ionic Distributions in Liquid Silicates: Application of Polymer Theory,Can. J. Chem., 1970, vol. 48, p. 1456.
Gaskell, D.R., Thermodynamic Models of Liquid Silicates,Can. Metall Q, 1981, vol. 20, no. 1, pp. 3–19.
Esin, O.A., The Nature of Molten Metallurgical Slags,Zh. Vses. Khim. O-va. im. D. I. Mendeleeva, 1974, vol. 16, no. 5, pp. 504–514.
Novikov, V.K., Evolution of the Polymer Model of Silicate Melts,Rasplavy, 1987, vol. 1, no. 6, pp. 21–33.
Pelton, A.D. and Blander, M., Thermodynamic Analysis of Ordered Solutions by Modified Quasichemical Approach-Application to Silicate Slags,Metall. Trans. B, 1986, vol. 17, pp. 807–815.
Haller, W., Blackburn, D.H., and Simmons, J.H., Miscibility Gaps in Alkali-Silicate Binaries-Data and Thermodynamic Interpretation,J. Am. Ceram. Soc., 1974, vol. 57, no. 3, pp. 120–126.
Moriya, Y., Warrington, D.H., and Douglas, R.W., Metastable Liquid Immiscibility in Some Binary and Ternary Alkali Silicate Glasses,Phys. Chem. Glasses, 1967, vol. 8, no. l, pp. 19–25.
Andreev, N.S., Goranov, D.A., Porai-Koshits, E.A., and Sokolov, Yu.G., Chemically Nonuniform Structure of Soda-Silica and Lithia-Silica Glasses, inStekloobraz- noe sostoyanie. Vyp. 1: Katalizirovannaya kristallizatsiya stekla (Glassy State. Issue 1: Catalyzed Glass Crystallization), Leningrad, 1963, pp. 46–53.
Andreev, N.S. and Aver’yanov, V.I., Structural Studies of Soda-Silica Glasses in the Range of Metastable Segregation,Trudy IV vsesoyuznogo soveshchaniya po stekloobraznomu sostoyaniyu (Proc. IV All-Union Conf. on Glassy State), Moscow,’ 1965, pp. 94–97.
Hammel, J.J.,Proc. VII Int. Congress on Glass, Charleroi, 1966, vol. 1, paper 36.
Porai-Koshits, E.A. and Averjanov, V.I., Primary and Secondary Phase Separation of Sodium Silicate Glasses,J. Non-Cryst. Solids, 1968, vol. 1, no. 1, pp. 29–38.
Charles, R.J., Origin of Immiscibility in Silicate Solutions,Phys. Chem. Glasses, 1969, vol. 10, no. 5, pp. 169–178.
Schlackenatlas, Düsseldorf: Stahleisen, 1981, p. 35.
Kracek, F.C., Bowen, N.L., and Morrey, G.W., Equilibrium Relations and Factors Influencing Their Determination in the System K2SiO3-SiO2,J. Phys. Chem., 1937, vol. 41, pp. 1183–1193.
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Zaitsev, A.I., Shelkova, N.E. & Mogutnov, B.M. Thermodynamics of Na2O-SiO2 melts. Inorg Mater 36, 529–543 (2000). https://doi.org/10.1007/BF02757949
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DOI: https://doi.org/10.1007/BF02757949