Preparation and Characterization of γ-Al2O3 by Polyaluminum Chloride with High Al13 Content

In this paper a polyaluminum chloride solution with high Al13 content was prepared and used as raw material for preparation of γ-Al2O3. The texture and crystalline phase of the prepared alumina samples were characterized by energy dispersive X-ray spectroscopy (EDX), X-ray diffraction, transmission electron microscope (TEM) and nuclear magnetic resonance (NMR) analyses. The effects of alkaline solution and calcination temperature were investigated. The results showed that alkaline solution including NH3·H2O and NaOH had little effect on the alumina sample formation. The impurities of NH4Cl and NaCl in solution can be removed through repeated washing by EDX analysis. Calcination temperature had a significant effect on alumina crystal phase. The alumina sample can transform completely to γ-Al2O3 in the subsequent heating from 600 °C to 800 °C. It is very interesting that Al13 can be existed in γ-Al2O3 phase even after calcinations. The results indicate that polyaluminum chloride with high Al13 content is an effective material to prepare γ-Al2O3.