Preparation of 0.85 nm Hydrated Kaolinite by Direct Displacement Intercalation

The hydrated kaolinite with d001=0.85 nm was prepared with simple direct displacement intercalation method by using kaolinite-urea intercalation compound as an intermediate.The microstructure and morphology of kaolinite before and after intercalation were characterized by X-ray diffraction,infrared spectroscopy and scanning electron microscopy.The results show that the basal spacing of the kaolinite increases from d001=0.72 nm to d001=1.08 nm after intercalation with urea.After being grafted with water through washing with acid or water at different temperatures,the hydrated kaolinite with d001=0.85 nm is obtained.And the grain thickness of kaolinite decreases significantly from 25 nm to about 10 nm.The highest content of the hydrated kaolinite appears at high temperature,which is nearly 70% by washing with water at 90 ℃.The d001=0.85 nm hydrated kaolinite derived from kaolinite-urea compound has further intercalation ability,and may serve as an excellent precursor for preparing other kaolinite intercalation compounds.The transformation rate of about 100% can be obtained for kaolinite-ethylene glycol intercalation compound from the hydrated kaolinite.