Modification of activated alumina

　　In order to overcome a series of problems such as the decrease in specific surface area and pore structure caused by high-temperature sintering and phase transformation of alumina, scholars from various countries have conducted research on the modification of the thermal stability of alumina. The main methods used include improving the preparation process, adding additives, and generating new substances. Improving the preparation process can improve the structure and morphology of alumina particles, reducing the loss of specific surface area; Adding additives can suppress the sintering of particles, stabilize the crystal structure of alumina, and increase the phase transition temperature; Generation of new substances refers to the generation of new high-temperature stable substances with a certain specific surface area on alumina to improve its stability.

　　At present, there is a lot of research mainly on improving the performance by adding additives γ- High temperature thermal stability of Al2O3. After years of practice and summary, additives used for modified alumina mainly fall into five categories, namely rare earth elements, alkaline earth elements, transition metals, silicon dioxide, and other oxides. Nowadays, rare earth La, Ce, and alkaline earth metal Ba are commonly used domestically and internationally to modify alumina, thereby improving the stability of activated alumina.

　　Summary

　　With the increasing development of chemical industry and the increasing emphasis on environmental protection, the market is increasingly concerned about γ- The demand for Al2O3 is rapidly increasing, which is crucial for γ- The performance of Al2O3 carriers requires higher requirements, and the preparation method is closely related to its performance. Currently, in industry, low-cost, green and environmentally friendly carbonization method is used for production γ- Al2O3 carrier technology is gradually popularized, and the sol gel method is becoming a new research hotspot in the field of carrier preparation. On the other hand, preparing high specific surface area, suitable pore size distribution, good thermal stability and hydration resistance γ- Al2O3 carriers will also receive increasing attention from people.