The fluorination mechanism of low-level fluorinated materials obtained by calcination of Bayer gibbsite at different temperatures was studied by ²⁷Al and ¹⁹F solid-state NMR spectroscopy and X-ray diffraction. Gibbsite was calcined at 400, 600, 800, and 1000 °C followed by treatment with anhydrous HF/N₂ gas at 100 °C. Three types of Al–F species on the surface of fluorinated gibbsite calcined at 400, 600, and 800 °C are proposed on the basis of the ¹⁹F magic angle spinning (MAS) NMR spectra, which show peaks at about −132, −137, and −163 ppm, while the spectrum of fluorinated gibbsite calcined at 1000 °C showed five additional peaks, at about −139, −164, −176, −183, and −191 ppm. The fluorination process in aluminas is based on elementary exchange reactions in which F⁻ replaces surface –OH groups according to their basicity. The ²⁷Al MAS NMR and ¹⁹F-²⁷Al cross-polarization–MAS experiments confirmed the presence of octahedral Al species.

采用²⁷ Al 和¹⁹ F 固态核磁共振谱和 X 射线衍射研究了拜耳三水铝石在不同温度下煅烧得到的低含量氟化材料的氟化机理。三水铝石在 400、600、800 和 1000 °C 下煅烧，然后在 100 °C 下用无水 HF/N ₂气体处理。在¹⁹F 魔角旋转 (MAS) NMR 光谱，在约 -132、-137 和 -163 ppm 处显示峰，而在 1000 °C 煅烧的氟化三水铝石的光谱显示出五个额外的峰，在约 -139、-164、 -176、-183 和 -191 ppm。氧化铝中的氟化过程基于元素交换反应，其中 F ^-根据其碱性替换表面 -OH 基团。在²⁷的Al MAS NMR和¹⁹ F- ²⁷的Al交叉极化-MAS实验证实八面体Al物质的存在。