Water solubility mechanism in hydrous aluminosilicate glasses: Information from Al-27 MAS and MQMAS NMR

摘要

New Al-27 NMR data are presented in order to clarify the discrepancies in the interpretation of the previous Al-27 Magic Angle Spinning (MAS) spectra from hydrous aluminosilicate glasses. The Al-27 MAS data have been collected at much higher magnetic field (14.1 and 17.6 T) than hitherto, and in addition, multiple quantum (MQ) MAS NMR data are presented for dry and hydrous nepheline glasses and NaAlSi7.7O17.4 glass that, according to the model of Zeng et al. (Zeng Q., Nekvasil H., and Grey C. P. 2000. In support of a depolymerisation model for water in sodium aluminosilicate glasses: Information from NMR spectroscopy. Geochim. Cosmochim. Acta 64, 883-896), should produce a high fraction (up to 30%) of Al in Al Q(3)-OH on hydration. Although small differences in the MAS spectra of anhydrous and hydrous nepheline glasses are observed, there is no evidence for the existence of significant (>similar to2%) amounts of Q(3) Al-OH in these glasses in either the MAS or MQMAS data. Copyright (C) 2003 Elsevier Science Ltd. [References: 44]