~29Si, ~27Al and ~23Na solid-state nuclear magnetic resonance studies of combustion-generated ash

摘要

Combustion-generated ash was synthesized, heated and analyzed by solid-state nuclear magnetic resonance spectroscopy with magic angle spinning(NMR-MAS). The structure information obtained from this study indicates that the ash contains different magnetic resonance environments for Al, Si and Na after combustion. The final ash material contains a major amorphous aluminoslicate glass phase with mullite corundum crystals. ~29Si NMR spectra showed a single peak at -110.5 ppm(δ)for the initial powder sample due to SiO_2. When the sample was heated to 1500 deg. C the peak shifts to lower field(δ=-99 ppm)due to the formation of aluminosilicate Amorphous glass containing alkali or alkaline earth metals.