A swelling mica, Na2Mg3(Al2Si2)O10F2·xH2O, (hereafter 'Na-4 mica') was synthesized from metakaolinite + MgO and Mg aluminosilicate gels at different temperatures and durations using NaF flux. The various samples were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and 27Al and 29Si magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. The results showed that phase-pure Na-4 mica was obtained from metakaolinite which serves as a cost-effective aluminosilicate source. 27Al MAS NMR spectra showed that all or nearly all Al is in tetrahedral coordination whereas 29Si MAS NMR spectra showed that the nearest neighbor environment of Si is mainly Si(3Al), as expected based on the Si:Al ratio.
All Science Journal Classification (ASJC) codes
- Water Science and Technology
- Soil Science
- Geochemistry and Petrology
- Earth and Planetary Sciences (miscellaneous)