Solid-state NMR characterisation of the thermal transformation of a Hungarian white illite.

摘要: 1H, 27Al, 29Si and 39K solid-state NMR are reported from a Hungarian illite 2:1 clay for samples heated up 1600 °C. This single-phase sample has small amount of aluminium substitution in the silica layer very low iron-content (0.4 wt%). Thermal analysis shows several events that can be related to features spectra, hence changes atomic scale structure. As dehydroxylation occurs there is increasing AlO4 AlO5-contents. The gibbsite layers become increasingly separated as progresses. Between 900 1000 °C forms potassium aluminosilicate glass. gibbsite-layer spinel/γ-Al2O3 some aluminium-rich mullite. Then on heating 27Al MAS spectra consistent with glass its aluminium-content, mullite probably silicon-content also increasing, α-Al2O3 forming.