Activated alumina physicochemical properties and preparation method

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[Physical and chemical properties] Activated alumina is a polar adsorbent, generally used as a catalyst carrier

Alumina is generally made by thermally decomposing alumina hydrates.

[Preparation method] (1) Preparation method

Activated alumina is usually obtained by heating and dehydrating aluminum hydroxide

① Acid neutralization method The acid neutralization method uses sodium aluminate as the raw material, and adds a certain concentration of acid or carbon dioxide gas under stirring to obtain aluminum hydroxide gel

In production, the prepared sodium aluminate solution, nitric acid solution and pure water are metered and fed into a neutralizer with stirring for neutralization reaction

② Alkali neutralization method Alkaline neutralization method is to neutralize the aluminum salt solution with ammonia water or other lye to obtain aluminum hydroxide gel

AlCl ₃ +3NH ₃ +3H ₂ O→AI(OH) ₃ ↓+3NH ₄ Cl

To neutralize aluminum chloride solution with ammonia water in production is to introduce the prepared aluminum chloride solution into the neutralizer first, add ammonia water under stirring, and then filter and slurry wash after the reaction is completed

③Aluminum sol method Alumina produced by the aluminum sol method is to digest metal aluminum in hydrochloric acid or aluminum chloride solution to obtain a transparent and colorless aluminum sol

④Aluminum alkoxide hydrolysis method.

(RO) ₃ Al+3H ₂ O→Al(OH) ₃ ↓+3R-OH

Usually aluminum isopropoxide is used as a raw material for hydrolysis: