Synthesis of crystalline γ-Al2O3 with high purity
(1. College of Materials Science and Engineering, North University of China, Taiyuan 030051, China;
2. Department of Chemistry, North University of China, Taiyuan 030051, China)
2. Department of Chemistry, North University of China, Taiyuan 030051, China)
Abstract: Crystalline γ-AlO(OH) was synthesized by the precipitation of sodium aluminate and oxalic acids in aqueous solution. And then γ-AlO(OH) was successfully transferred to γ-Al2O3 after subsequent high temperature heat treatment. The effects of reaction conditions on formation of γ-AlO(OH) and γ-Al2O3 were further investigated in detail. The XRD analysis shows that the complete formation of crystalline γ-Al2O3 is at pH 8−9, reaction temperature of 93−96 ℃ and calcination temperature of higher than 400 ℃. The product of γ-Al2O3 contains impurity, including iron, calcium and silicon ion with a low content of about 0.01% and has large specific surface area and high pore volume of 269.9 m2/g and 0.57 mL/g, which can be applied in catalysts and catalyst supports.
Key words: γ-Al2O3; high purity; sodium aluminate; oxalic acids