Synthesis of crystalline γ-Al_2O_3 with high purity

Crystallineγ-AlO(OH)was synthesized by the precipitation of sodium aluminate and oxalic acids in aqueous solution. And thenγ-AlO(OH)was successfully transferred toγ-Al2O3 after subsequent high temperature heat treatment.The effects of reaction conditions on formation ofγ-AlO(OH)andγ-Al2O3 were further investigated in detail.The XRD analysis shows that the complete formation of crystallineγ-Al2O3 is at pH 8-9,reaction temperature of 93-96℃and calcination temperature of higher than 400℃.The product ofγ-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.

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 m^2/g and 0.57 mL/g, which can be applied in catalysts and catalyst supports.