Solubility mechanisms of fluorine in NaAlO/sub 2/-SiO/sub 2/-F, SiO/sub 2/-AlF/sub 3/ and SiO/sub 2/-NaF melts at 1 ATM
The interaction between fluorine and sodium aluminosilicate melts (Al/(Al+Si)=0.125=0.250 on the join NaAlO/sub 2/-SiO/sub 2/) and melts on the joins SiO/sub 2/-NaF and SiO/sub 2/-AlF/sub 3/ has been studied with Raman spectroscopy. Fluorine is dissolved to form F/sup -/ ions that are electrically neutralized with Na/sup +/ or Al/sup 3 +/. In sodium aluminosilicate melts there is no evidence for four-fold coordination of fluorine with either Si/sup 4 +/ or Al/sup 3 +/ and no evidence of fluorine in six-fold coordination with Si/sup 4 +/, whereas some F replaces bridging oxygens in melts on the joins SiO/sub 2/-AlF/sub 3/ and SiO/sub 2/-NaF. Nonbridging oxygens are formed and are a part of structural units with nonbridging oxygen per tetrahedral cations (NBO/T) near 2 and 1. The proportions of these two depolymerized units increase systematically with increasing F/(F+O) at constant Al/(Al+Si) and with decreasing Al/(Al+Si) at constant F/(F+O). The structural data have been used to develop a method to calculate the viscosity of fluorine-bearing sodium aluminosilicate melts at 1 atm. Where experimental viscosity data are available, the calculated and measured values are within 5% of each other. A method is also suggested with which the liquidus phase equilibria of fluorine-bearing aluminosilicate melts may be predicted. In accord with published experimental data it is suggested on the basis of the determined solubility mechanism of fluorine in aluminosilicate melts that with increasing fluorine content of feldspar-quartz systems, the liquidus boundaries between aluminosilicate minerals (e.g., feldspars) and quartz shift away from silica, for example.
- Research Organization:
- Geophysical Lab., Washington, DC (USA)
- OSTI ID:
- 6193731
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Vol. 17; ISSN GAAPB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580300 -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
580400* -- Geochemistry-- (-1989)
ALKALI METAL COMPOUNDS
ALUMINIUM COMPOUNDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISTRY
FLUORINE COMPOUNDS
GEOCHEMISTRY
HALOGEN COMPOUNDS
IGNEOUS ROCKS
KINETICS
LASER SPECTROSCOPY
MAGMA
MAGMATISM
MINERALIZATION
MINERALOGY
MINERALS
MOLECULAR STRUCTURE
PETROGENESIS
RAMAN SPECTROSCOPY
REACTION KINETICS
ROCKS
SILICATE MINERALS
SODIUM COMPOUNDS
SOLUBILITY
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS