γ-type alumina is produced by dehydration of aluminum hydroxide at a low temperature of 140-150°C. It is also called activated alumina and aluminum glue in industry. In its structure, the oxygen ions are approximately densely packed in the vertical plane, and AL3+ is irregularly distributed in the octahedral and tetrahedral voids surrounded by oxygen ions. γ-type alumina is insoluble in water and can be dissolved in strong acid or strong alkali solution. When heated to 1200°C, it will be completely converted into α-type alumina. γ-type alumina is a porous material, with an internal surface area of up to several hundred square meters per gram, with high activity and strong adsorption capacity. Industrial products are often colorless or slightly pink cylindrical particles with good pressure resistance. It is a commonly used adsorbent, catalyst and catalyst carrier in petroleum refining and petrochemical industry; it is a deacidification agent for transformer oil and turbine oil in industry; it is also used for chromatographic analysis; it is a neutral strong desiccant in the laboratory. Its drying capacity is no less than that of phosphorus pentoxide. After use, it can be regenerated and reused after heating for 6-8 hours below 175°C.