PL EN


Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników
Czasopismo
2007 | 5 | 2 | 508-515
Tytuł artykułu

Thermochemical properties of the Fe-analogue of cryolite, Na3FeF6

Treść / Zawartość
Warianty tytułu
Języki publikacji
EN
Abstrakty
EN
Relative enthalpies for low-and high-temperature modifications of Na3FeF6 and for the Na3FeF6 melt have been measured by drop calorimetry in the temperature range 723–1318 K. Enthalpy of modification transition at 920 K, δtransH(Na3FeF6, 920 K) = (19 ± 3) kJ mol−1 and enthalpy of fusion at the temperature of fusion 1255 K, δfusH(Na3FeF6, 1255 K) = (89 ± 3) kJ mol−1 have been determined from the experimental data. Following heat capacities were obtained for the crystalline phases and for the melt, respectively: C p(Na3FeF6, cr, α) = (294 ± 14) J (mol K)−1, for 723 = T/K ≤ 920, C p(Na3FeF6, cr, β) = (300 ± 11) J (mol K)−1 for 920 ≤ T/K = 1233 and C p(Na3FeF6, melt) = (275 ± 22) J (mol K)−1 for 1258 ≤ T/K ≤ 1318. The obtained enthalpies indicate that melting of Na3FeF6 proceeds through a continuous series of temperature dependent equilibrium states, likely associated with the production of a solid solution. [...]
Słowa kluczowe
Wydawca

Czasopismo
Rocznik
Tom
5
Numer
2
Strony
508-515
Opis fizyczny
Daty
wydano
2007-06-01
online
2007-02-27
Twórcy
autor
  • Institute of Inorganic Chemistry, Slovak Academy of Sciences, 845 36, Bratislava, Slovak Republic, ivan.nerad@savba.sk
  • Institute of Inorganic Chemistry, Slovak Academy of Sciences, 845 36, Bratislava, Slovak Republic
Bibliografia
  • [1] K. Grjotheim, C. Krohn, M. Malinovský, K. Matiašovský and J. Thonstad: Aluminium Electrolysis, Fundamentals of the Hall-Héroult Process, 2nd ed., Aluminium Verlag, Düsseldorf, 1982.
  • [2] Å. Sterten, P.A. Solli and E. Skybakmoen: “Influence of Electrolyte Impurities on Current Efficiency in Aluminium Electrolysis Cells”, J. Appl. Electrochem., Vol. 28, (1998), pp. 781–789. http://dx.doi.org/10.1023/A:1003425901393[Crossref]
  • [3] J. Thonstad: “The Behaviour of Impurities in Aluminium Cells”, In: Proc. Tenth Slovak-Norwegian Symposium on Aluminium Smelting Technology, Stará Lesná - Žiar nad Hronom, Slovakia, 1999, pp. 5–12.
  • [4] H.G. Johansen: Jern som forurensningselement i aluminiumelektrolysen, Thesis (PhD), Department of Electrochemistry, Norwegian Institute of Technology, Trondheim, Norway, 1975.
  • [5] B.Q. Diep: Structure and Thermodynamics of Cryolite Based Melts with Additions of Al 2O 3and Fe 2O 3, Thesis (PhD), Department of Electrochemistry, Norwegian University of Science and Technology, Trondheim, Norway, 1998.
  • [6] F. Šimko and V. Daněk: “Cryoscopy in the System Na3AlF6 − Fe2O3”, Chem. Pap., Vol. 55, (2001), pp. 269–272.
  • [7] F. Šimko, A. Rakhmatullin, C. Bessadaa, V. Daněk and M. Boča: “Structure of Na3AlF6 − FeO and Na3AlF6 − Fe2O3 Melts: A multinuclear NMR Study”, In: Proc. 7th International Symposium on Molten Salt Chemistry and Technology, Vol. 1, Toulouse, France, 2005, pp. 351–354.
  • [8] F. Šimko, A. Rakhmatullin, M. Boča, V. Daněk and C. Bessadaa: “A High-Temperature Multinuclear NMR Study of Na3AlF6 − FeO and Na3AlF6 − Fe2O3 Melts”, Eur. J. Inorg. Chem., (2006), pp. 4528–4532. [Crossref]
  • [9] W.J. Croft and M. Kestigian: “The crystallography of Na3FeF6”, Mater. Res. Bull., Vol. 3, (1968), pp. 571–575. http://dx.doi.org/10.1016/0025-5408(68)90088-3[Crossref]
  • [10] E.N. Matvienko, O.V. Jakubovich, M.A. Simonov, A.N. Ivaschenko, O.K. Mel’nikov and N.V. Belov: “Crystal Structure of Synthetic Fe-Cryolite Na3FeF6”, Dokl. Akad. Nauk SSSR, Vol. 257, (1981), pp. 105–108.
  • [11] H.D. De Young: “Solubilities of Oxides for Inert Anode in Cryolite-Based Melts”, In: R.E. Miller (Ed.): Light Metals, TMS, Warrendale, PA., USA, 1986, pp. 299–307.
  • [12] I. Proks, M. Eliášová, I. Zlatovský and J. Záuška: ”High-temperature Drop Calorimeter for the Determination of Increase in Enthalpy”, Silikáty, Vol. 21, (1977), pp. 253–264.
  • [13] I. Zlatovský: “Evaluation of Calorimetric Measurements on the Basis of an Analysis of Calorimeter Thermal Losses“, Silikáty, Vol. 21, (1977) pp. 71–76.
  • [14] A. Tressaud, J. Portier, R. de Pape and P. Hagenmuller: “Les systèmes MF-FeF3 (M = Li, Na, K, Rb, Cs, Tl, NH4)”, J. Solid State Chem. Vol. 2, (1970), pp. 269–277. http://dx.doi.org/10.1016/0022-4596(70)90079-4[Crossref]
  • [15] E.E. Dewing and J. Thonstad: “Solutions of Iron Oxides in Molten Cryolite”, Metal. Mater. Trans. B, Vol. 31B, (2000), pp. 609–613. http://dx.doi.org/10.1007/s11663-000-0098-8[Crossref]
  • [16] O. Knacke, O. Kubashewski and K. Hesselmann: Thermochemical Properties of Inorganic Substances, 2nd ed., Springer Verlag, Berlin, 1991.
Typ dokumentu
Bibliografia
Identyfikatory
Identyfikator YADDA
bwmeta1.element.-psjd-doi-10_2478_s11532-007-0015-y
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.