Mechanism of Mechanochemical Reactions in Magnesium-Aluminium Layered Double Hydroxides Systems

The mechanochemical synthesis and formation mechanisms of magnesium- aluminium-layered double hydroxides (MgAl LDHs) by ball-mill were investigated. In order to verify the structure of LDHs, X-ray diffraction (XRD) patterns, scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) were characterized. The results show that flower-like particles with high crystallinity are obtained. The R values (Mg/Al molar ratio) of samples are higher than feed ratios. This approach includes two processes, activation and diffusion. The magnesium hydroxide must be activated. The diffusion leaded to isomorphously substituted between Mg2+ ions and Al3+ ions in hot water and synthesized the MgAl LDHs.