Structure and thermodynamics of alkali fluoride-aluminum fluoride-alumina melts. Vapor pressure, solubility, and Raman spectroscopic studies

被引:134
作者
Robert, E
Olsen, JE
Danek, V
Tixhon, E
Ostvold, T
Gilbert, B
机构
[1] UNIV LIEGE,CHIM ANALYT LAB,B-4000 LIEGE,BELGIUM
[2] NORWEGIAN UNIV SCI & TECHNOL,INST INORGAN CHEM,N-7034 TRONDHEIM,NORWAY
[3] SLOVAK ACAD SCI,INST INORGAN CHEM,BRATISLAVA 84236,SLOVAKIA
来源
JOURNAL OF PHYSICAL CHEMISTRY B | 1997年 / 101卷 / 46期
关键词
D O I
10.1021/jp9634520
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The MF-AlF3-Al2O3 (M = Li, Na, K) systems have been studied in the liquid state. Raman spectra were recorded to obtain information on the structure and the ionic composition of these melts, vapor pressure measurements were performed to obtain thermodynamic information, and the Al2O3 solubility has been measured as a function of the melt composition and temperature. These data show that the ions AlF4-, AlF52-, AlF63-, and F- exist together with the oxyanions Al2OF62-, Al2O2F42-, and possibly Al3O4F43-. For the NaF- and KF-containing systems, the solubility of Al2O3 increases very much with the mole ratio n degrees(MF)/n degrees(AlF3) and is maximum at n degrees(MF)/n degrees(AlF3) = 4 (8.1 mol % at 1040 degrees C for the NaF-AlF3 mixtures, 16.8 mol % at 1027 degrees C for the KF-AlF3 mixtures). For the LiF-AlF3 system the Al2O3 Solubility is much smaller with a maximum of approximate to 2.2 mol % probably around n degrees(MF)/n degrees(AlF3) = 1.5 at 1000 degrees C. The four equilibria AlF63- = AlF52- + F-, AlF52- = AlF4- + F-, 2Al(2)OF(6)(2-) + 2F(-) = Al2O2F42- + 2AlF(5)(2-), 2Al(2)O(2)F(4)(2-) + F- = Al3O4F43- + AlF52-, can give a reasonable explanation of the observed Raman, vapor pressures, and solubility data.
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收藏
页码:9447 / 9457
页数:11
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