Publication Title
Journal of Non-Crystalline Solids
Document Type
Article
Department or Program
Geology
Publication Date
11-15-2019
Keywords
viscosity, aluminosilicate melts, alkali mixing, configurational entropy modelling
Abstract
We provide new viscosity data in the system SiO2-(Na,K)AlSiO4, for the nepheline-kalsilite and jadeite-leucite joins. We present a configurational entropy model for the viscosity of melts in the system as a function of Na/(Na+K) and Al/(Al+Si) ratios. Our modelling indicates that: i) Viscosity data are reproduced well by a non-ideal, symmetrical form of the parameters Sconf (Tg) and Be, ii) Na-K mixing is the main source of additional entropy in the system based on the limited dependence of Sconf (Tg) and Be parameters on Al/(Al+Si) ratio, iii) Ae likely varies as a function of Al/(Al+Si) ratio. Melt fragility in the system increases with increasing Al/(Al+Si) ratio and is greater for Na or K end-member melts than mixed melts. The viscosity of nominally fully-polymerized melts in the SiO2- (Na,K)AlSiO4 system can be modelled through chemical mixing, without explicit consideration of the important changes in structure related to changes in K/(Na+K) and Al/(Al+Si) ratios.
Recommended Citation
Robert, G., Smith, R. A. and Whittington, A. G., (2019) Viscosity of melts in the NaAlSiO4-KAlSiO4-SiO2 system: configurational entropy modelling. Journal of Non-Crystalline Solids. 524. https://doi.org/10.1016/j.jnoncrysol.2019.119635
Copyright Note
This is the author's version of the work. This publication appears in Bates College's institutional repository by permission of the copyright owner for personal use, not for redistribution.
Required Publisher's Statement
© 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Comments
Original version is available from the publisher at: https://doi.org/10.1016/j.jnoncrysol.2019.119635