1.1. Material Properties
Pseudo-boehmite (AlOOH·nH2O) is widely used in fields such as petroleum catalysis, automotive exhaust treatment, flame-retardant materials, and environmental adsorption due to its high specific surface area and large pore volume. Its preparation methods include the aluminum alcohol method, carbonization method, and acid method. It is a key raw material for the production of high-performance nano-γ -alumina.
1.2. Applications in the Petroleum Industry
In the petroleum industry, pseudo-boehmite is often used as a catalyst and carrier, playing a significant role in the reaction process.
1.3. Other industry applications
In the automotive industry, pseudo-boehmite is used as a carrier coating in automotive catalytic converters to enhance the efficiency of exhaust gas treatment.
In the fire protection and papermaking industries: In the field of fire protection, pseudo-boehmite is used as an additive for flame-retardant materials to enhance their flame-retardant performance. In the papermaking industry, it is used as an ink-absorbing coating in high-end inkjet printing paper to enhance the ink absorption performance of the paper.
Environmental protection and construction industry: Pseudo-boehmite can be used as a gas purification adsorbent, and is also used to remove fluoride from drinking water and eliminate the color and odor of industrial wastewater. In the construction industry, it is used as a coating additive to enhance the performance of coatings.
Ceramic composites: Pseudo-boehmite is used as a reinforcing agent in ceramic composites to enhance their strength and durability
2. Preparation method of pseudo-boehmite
2.1. Aluminum alcohol method
The aluminum alcohol method is one of the main methods for preparing high-purity pseudo-boehmite at present. This method was first adopted by the German company Condea, using metallic aluminum and higher alcohols as raw materials. During the preparation process, metallic aluminum reacts with alcohol to form aluminium hydroxide, which is then converted into new aluminium hydroxide by reducing aldehydes or ketones. Finally, pseudo-boehmite is obtained through hydrolysis. The pseudo-boehmite generated by this method has extremely high purity, but the process is rather complex and the pore size is small, making it difficult to meet the requirements of some large-pore applications.
2.2. Carbonization Method (Alkali Method)
In industry, the low-cost carbonization method is mainly adopted to produce pseudo-boehmite. This process consists of four steps: gelation, aging, separation and washing, and drying. During the gelation process, sodium aluminate solution is transformed into amorphous aluminum hydroxide and other substances by introducing carbon dioxide. It is worth noting that the products of this method have a relatively high impurity content and a relatively low crystal phase purity.
2.3. Acid method
Pseudo-boehmite is prepared by the acid method through neutralization reaction with soluble alkali. This method can effectively control crystal growth and has low impurities, making it highly suitable for use as a catalyst carrier. The specific steps include gelation, aging, washing and drying, etc.
3. Detailed analysis of the application
3.1. Nano γ -alumina
Pseudo-boehmite is a key raw material for the preparation of nano-γ -alumina. This kind of alumina not only retains the high specific surface area and high activity of the raw material, but also performs well in chemical mechanical polishing (CMP). The CMP slurry produced is particularly suitable for the production of integrated circuits and can also enhance the polishing effect of high-grade optical glass and quartz crystals.
3.2. Applications in Hydrogenation Catalysts
In hydrogenation catalysts, γ -alumina is an important material for preparing catalysts. It is obtained through the calcination and dehydration process of pseudo-boehmite, featuring an excellent specific surface area and controllable pore structure. These characteristics make it indispensable as a catalyst carrier in fields such as petrochemicals.
3.3. Adhesive and Coating Preparation
Pseudo-boehmite, as a binder, enhances the mechanical strength and catalytic performance of the carrier during the catalyst preparation process. In the process of coating highly active γ-Al2O3, pseudo-boehmite is often used as a precursor to further enhance the activity and stability of the catalyst.