Thermal decomposition study of hydrotalcite-like compounds

Thermal decomposition of hydrotalcite-like compounds with formula MgxAl1-x(CO3)(x/2)(.)nH(2)O has been studied varying the molar ratio (x) between Mg and Al cations. Compounds synthesized by coprecipitation method at fixed pH, have been fired at different temperatures between 500 and 1200 degreesC with different remaining times. This study has been carried out by Differential Thermal and Thermogravimetric Analysis (DTA/TG), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Al-27 Nuclear Magnetic Resonance (Al-27-MAS-NMR) Main results show that the optimum molar ratio (x) to hydrotalcite phase formation is between 0.20 and 0.35, obtaining spinel (MgAl2O4) and Periclase (MgO) as the decomposition compounds.