Pseudo boehmite, also known as pseudo boehmite, is a kind of aluminum hydroxide with fine particles, incomplete crystallization, porous and thin folded lamella. It has good adhesion after gelling and can produce Y-Al, 0 with rich pore structure after heat treatment. Therefore, the catalytic cracking of pseudo boehmite containing gelling (FCC) catalyst has rich mesoporous structure and good heavy oil conversion ability.
It can be used as the binder of semi synthetic rare earth Y-type molecular sieve cracking catalyst, the binder of aluminum silicate refractory fiber, the catalyst for alcohol dehydration to ethylene and oxyethane, as well as the raw material for the production of catalyst carrier, activated alumina and other aluminum salts.
Aluminum hydroxide is also called hydrated alumina, and its chemical formula is Al2O3 · nH2O. When n = 1, Al2O3 · H2O is called hydrated alumina, which is divided into three types: diaspore, boehmite and pseudo boehmite. The main difference between boehmite and pseudo boehmite is grain size.
Alumina has many crystal forms, and the crystal forms of alumina prepared by calcining aluminum hydroxide under different conditions are different γ- Al2O3 is a transition alumina widely used in industry, also known as activated alumina. γ- Al2O3 has a large specific surface area and can be used as a carrier for more metals or metal oxides. Its pore size is adjustable and its thermal stability is good. It is often used as a catalyst carrier for hydrogenation, reforming, methanol synthesis and other reactions.
At present, most industrial activated alumina is obtained by calcining pseudo boehmite, which is widely used in oil refining and automobile industry Alumina with large pore size first needs to prepare boehmite or pseudo boehmite precursor with large specific surface area. The morphology and particle size of pseudo boehmite determine the morphology and specific surface area of alumina. At present, the preparation methods of pseudo boehmite mainly include acid precipitation method, alkali precipitation method, alcohol aluminum method and sodium aluminate carbon dioxide method.
The above is about the difference between pseudo boehmite and boehmite. As another important precursor of activated alumina, boehmite has a chemical composition similar to pseudo boehmite. It is an activated alumina precursor with high order and complete crystallization, so it has better stability than pseudo boehmite.