Abstract: Samples of Mg/Al and Mg/Zn/Al hydrotalcite were synthesized by coprecipitation method,and characterized by XRD,FT-IR,SEM,TG/DTG,particle analysis,and so on.Effect of different mix ratios of Mg,Al,and Zn on structure and thermal property of hydrotalcite was studied.XRD results showed that the synthesized substances all had the characteristic peaks of hydrotalcite.And it was demonstrated that the density of atoms in the layer decreased and the distance of the layers increased with the increasing of Mg/Al ratio;the density of atoms in the layer increased,and the distance of the layer decreased with the increasing of Zn ratio.There were two evidence phases in pyrolysis process of Mg/Al hydrotalcite.At first,the interlayer crystal waters were removed.Next,the interlayer anions were removed and part of the hydroxyls were dehydrated.But the Mg/Zn/Al hydrotalcite had only one thermal decomposition stage:anions and crystal waters between the the layers were decomposed at the same time.

Key words: hydrotalcite, synthesis, characterization