The alumina used in the catalytic agent, we usually call it Activated alumina. It is a kind of porous, highly dispersed solid material, with large superficial area. And The microporous surface has the characteristics required for the catalytic action, like Adsorption properties, surfactivity, and Excellent thermal stability. So it is widely used as Catalyst and catalyst carrier for the chemical reaction. The spherical activated alumina varipressure oil sorbent is white spherical porous particles. The is activated alumina is epigranular, with smooth surface, large mechanical strength, strong hygroscopic. While it is absorbing water, it won’t swell or crack but maintain the original state. And it is innoxious, odorless, and Insoluble in water or ethanol. Active alumina is a highly efficient desiccant with trace water depth drying for heat-free regeneration devices.
Alumina, commonly known as bauxite, has the chemical formula Al2O3. White powder, with 3.9~4.0g/cm3 density, melting point 2050℃, boiling point 2980℃. It is insoluble in water but can slowly dissolve in concentrated sulfuric acid. It can be used for making metal aluminum and is also raw materials for making crucibles, porcelain, refractory materials and artificial gemstones. Aluminum used as sorbent, catalyst and catalyst carrier is called "active alumina", which has porous, high dispersion and large surface accumulation characteristics, widely used in petrochemical, fine chemical, biological and pharmaceutical fields.
Active alumina is generally made by aluminum hydroxide heating and dehydration. Aluminum hydroxide is also known as hydration alumina, its chemical composition is Al2O3·nH2O. According to the number of crystalline water contained, it can usually be divided into trihydrate alumina and monohydrate alumina. After aluminum hydroxide is heated and dehydrated, γ-Al2O3 can be obtained. That is, commonly known as activated alumina.?
Activated alumina belongs to the category of chemical alumina, which is mainly used for adsorbent, water purification agent, catalyst and catalyst carrier. Activated alumina has selective adsorption of gases, water vapors and certain liquids. After adsorption saturation, it can be resurrected at about 175~315℃ for heating to remove the water. Adsorption and resurrection can be performed multiple times. Besides used as a desiccant, it can absorb oil vapor from contaminated oxygen, hydrogen, carbon dioxide, natural gas etc. And It can be used as catalyst and catalyst carrier and color layer analysis carrier. It can be used as defluoragent in the high-fluorinated drinking water (with high capacity), defluorination agent for circulating alkanes in the production of alkylbenzene, deacidification regenerator for the transformer oil. And it also can be used as gas drying in oxygen making industry, textile industry and electronic industry, automatic instrument air drying, chemical fertilizer, petrochemical drying and other industries as desiccant and purification agent (the dew point could be -40℃), the PSA ignition point in air distribution industry could reach -55℃. It is a highly efficient desiccant with deep drying of trace water which is very suitable for heat-free regeneration devices.
There are two raw materials for activated alumina production, one is the “quick de pulverization” made by gibbsite or bayerite. The other is pseudo boehmite produced simultaneously by aluminates or aluminum salts or both.?
x-ρ the production of alumina
x-ρ alumina is the main raw material of activated alumina balls, FCA abroad. In China, the alumina powder is produced by rapid dehydration method,, so we call it quick de pulverization. It is the mixture of x- alumina and ρ- alumina. The content varies due to the differences in the production conditions.
Production method of Pseudo Boehmite
The trihydrate alumina and monohydrate alumina produced by natural or artificially cannot be used as a desiccant, adsorbent, catalyst and catalyst carrier because of lower than the surface area, small pore capacity, and low activity. The trihydrate alumina and monohydrate alumina must be processed into Pseudo Boehmite. It is higer than the surface area and has large pore capacity, large aperture, and high activity, It is suitable for catalyst and catalyst carrier in desiccant, adsorbent and chemical fertilizer and exhaust gas