MSA  Vol.12 No.4 , April 2021
Thermodynamic Properties of CaCl2-CaF2-CaO System: Phase Diagram Investigation
Abstract: The CaCl2-CaF2-CaO phase diagram was investigated in the CaO low region (<40 mol.%). CaCl2-CaF2 and CaCl2-CaO binary diagrams, constituting the ternary system, were first studied by Differential Scanning Calorimetry (DSC) measurements and X-Ray Diffraction (XRD) characterization; a good agreement was obtained between the phase diagram models calculated with FactSage&reg; software (FTsalt database) and present experimental data. As the CaF2-CaO liquidus could not be measured by DSC due to the high melting temperature, this diagram was calculated using FTsalt database combined with FToxid database of FactSage&reg; software. The ternary phase diagram was obtained by calculations and exhibits an eutectic at the composition CaCl2-CaF2-CaO (78.2-15.7-6.1 mol.%) melting at 637&deg;C, and five peritectic points. Measurements of relevant vertical cross-sections for three CaCl2-CaF2 compositions (50-50, 40-60 and 30-70 mol.%) up to 18 mol.% CaO are in agreement with the ternary phase diagram model. For each section, the liquidus temperature is constant up to around 11 mol.% CaO and then sharply increases. Moreover, an increase of CaF2 content in CaCl2-CaF2 melt leads to a decrease of the CaO solubility in isothermal condition.
Cite this paper: Claquesin, J. , Gibilaro, M. , Massot, L. , Lemoine, O. , Bourges, G. and Chamelot, P. (2021) Thermodynamic Properties of CaCl2-CaF2-CaO System: Phase Diagram Investigation. Materials Sciences and Applications, 12, 139-151. doi: 10.4236/msa.2021.124009.

[1]   Wenz, D.A., Johnson, I. and Wolson, R.D. (1969) CaCl2-Rich Region of the CaCl2-CaF2-CaO System. Journal of Chemical & Engineering Data, 14, 250-252.

[2]   Krause, I.E. and Bergman, A.G. (1942) Singular Irreversible-Reciprocal Systems without Separation into Layers from Potassium and Calcium and Calcium Chlorides and Fluorides, and Sodium and Calcium Chlorides and Fluorides. Doklady Akademii Nauk SSSR, 35, 20-24.

[3]   Bukhalova, G.A. (1959) The Ternary Resiprocal System Formed by Fluorides and Chlorides of Sodium and Calcium. Russian Journal of Inorganic Chemistry, 4, 47-49.

[4]   Bukhalova, G.A. and Bergman, A.G. (1949) Troinaya vzaimnaya sistema iz ftoridov i khloridov litiya i kaltsiya. Doklady Akademii Nauk SSSR, 66, 67-70.

[5]   Plato, W. (1907) Erstarrungserscheinungen an anorganischen Salzen und Salzgemischen II. Zeitschrift für Physikalische Chemie, 58, 350-372.

[6]   Desyatnik, V.N., Kurbatov, N.N., Strelov, V.A. and Shchavelevc, V.V. (1979) Melting Point Diagrams of Systems Containing Potassium and Calcium Fluoride. Izv Vysshikh Uchebnykh Zaved Tsvetnaya Metall, 4, 65-68.

[7]   Messer, C.E. (1970) Hydrides versus Fluorides: Structural Comparisons. Journal of Solid State Chemistry, 2, 144-155.

[8]   Chartrand, P. and Pelton, A.D. (2001) Thermodynamic Evaluation and Optimization of the Li, Na, K, Mg, Ca//F, Cl Reciprocal System Using the Modified Quasi-Chemical Model. Metallurgical and Materials Transactions A, 32, 1417-1430.

[9]   Arndt, K. and Loewenstein, W. (1909) Uber Losungen von Kalk und Kieselsaure in geschmolzenem Chlorcalcium. Zeitschrift für Elektrochemie und angewandte physikalische Chemie, 15, 784-790.

[10]   Neumann, B., Kroger, C. and Jüttner, H. (1935) Die Systeme Erdalkalichlorid-Erdalkalioxyd und die Zersetzung der Erdalkalichloride durch Wasserdampf. Zeitschrift für Elektrochemie und angewandte physikalische Chemie, 41, 725-736.

[11]   Perry, G.S. and Macdonald, L.G. (1985) Role of CaCl2 in the Reduction of PuO2. Journal of Nuclear Materials, 130, 234-241.

[12]   Shaw, S. and Watson, R. (2009) Solubility of Calcium in CaCl2-CaO. ECS Transactions, 16, 301-308.

[13]   Threadgill, W.D. (1965) The Calcium Chloride-Calcium Oxide Fused Salt Electrolytic System: Solubilities, Metal Contents, and Freezing Points. Journal of The Electrochemical Society, 112, 632-633.

[14]   Freidina, E.B. and Fray, D.J. (2000) Study of the Ternary System CaCl2-NaCl-CaO by DSC. Thermochimica Acta, 356, 97-100.

[15]   Wang, S., Zhang, F., Liu, X. and Zhang, L. (2008) CaO Solubility and Activity Coefficient in Molten Salts CaCl2–x (x=0, NaCl, KCl, SrCl2, BaCl2 and LiCl). Thermochimica Acta, 470, 105-107.

[16]   Patnaik, P. (2003) Handbook of Inorganic Chemicals. Vol. 529, McGraw-Hill, New York.

[17]   Seo, W.-G., Zhou, D. and Tsukihashi, F. (2005) Calculation of Thermodynamic Properties and Phase Diagrams for the CaO-CaF2, BaO-CaO and BaO-CaF2 Systems by Molecular Dynamics Simulation. Materials Transactions, 46, 643-650.

[18]   Seo, W.-G., Zhou, D., Hamano, T. and Tsukihashi, F. (2004) Calulation of Phase Diagrams for the CaO-CaF2 and CaO-BaO Binary Systems by Using Molecular Dynamics. 7th International Conference on Molten Slags Fluxes and Salts, Cape Town, 25-28 January 2004, 835-838.

[19]   Zaitsev, A.I., Zemchenko, M.A., Litvina, A.D. and Mogutnov, B.M. (1993) Thermodynamic Calculation of Phase Equilibria in the CaF2-SiO2-CaO System. Journal of Materials Chemistry, 3, 541-546.

[20]   Kim, D.-G., Van Hoek, C., Liebske, C., Van Der Laan, S., Hudon, P. and Jung, I.-H. (2012) Phase Diagram Study of the CaO-CaF2 System. ISIJ International, 52, 1945-1950.

[21]   Kim, D.-G., Van Ende, M.-A., Van Hoek, C., Liebske, C., Van Der Laan, S. and Jung, I.-H. (2012) A Critical Evaluation and Thermodynamic Optimization of the CaO-CaF2 System. Metallurgical and Materials Transactions B, 43, 1315-1325.

[22]   Mukerji, J. (1965) Phase Equilibrium Diagram CaO-CaF2-2CaO.SiO2. Journal of the American Ceramic Society, 48, 210-213.

[23]   Chatterjee, A.K. and Zhmoidin, G.I. (1972) The Phase Equilibrium Diagram of the System CaO-Al2O3-CaF2. Journal of Materials Science, 7, 93-97.

[24]   Ries, R. and Schwerdtfeger, K. (1980) Contribution to the Phase Diagram CaF2-CaO-Al2O3. Archiv für das Eisenhüttenwesen, 51, 123-129.

[25]   Davies, M.W. and Wright, F.A. (1970) Viscosity of Calcium Fluoride-Based Slags. Chemistry & Industry, 11, 359-363.

[26]   Baak, T. (1954) The System CaO-CaF2. Acta Chemica Scandinavica, 8, 1727.

[27]   Bale, C.W., Chartrand, P., Degterov, S.A., Eriksson, G., Hack, K., Ben Mahfoud, R., Melancon, J., Pelton, A.D. and Petersen, S. (2002) FactSage Thermochemical Software and Databases. Calphad, 26, 189-228.

[28]   Bale, C.W., Bélisle, E., Chartrand, P., Decterov, S.A., Eriksson, G., Hack, K., Jung, I.-H., Kang, Y.-B., Melancon, J., Pelton, A.D., Robelin, C. and Petersen, S. (2009) FactSage Thermochemical Software and Databases—Recent Developments. Calphad, 33, 295-311.

[29]   Hohne, G.W.H., Hemminger, W. and Flammersheim, H.-J. (1996) Differential Scanning Calorimetry: An Introduction for Practitioners. Springer, Berlin, Heidelberg.

[30]   Tammann, G. (1903) über die Ermittelung der Zusammensetzung chemischer Verbindungen ohne Hilfe der Analyse. Zeitschrift für anorganische Chemie, 37, 303-313.

[31]   Guenet, J.M. (1996) Contributions of Phase Diagrams to the Understanding of Organized Polymer-Solvent Systems. Thermochimica Acta, 284, 67-83.

[32]   Rycerz, L. (2013) Practical Remarks Concerning Phase Diagrams Determination on the Basis of Differential Scanning Calorimetry Measurements. Journal of Thermal Analysis and Calorimetry, 113, 231-238.

[33]   Sano, N., Tsukihashi, F. and Tagaya, A. (1991) Thermodynamics of Phosphorus in CaO-CaF2-SiO2 and CaO-CaF2-CaCl2 Melts Saturated with CaO. ISIJ International, 31, 1345-1347.