The classification of Activated alumina
Activated alumina refers to intermediate alumina, which can be mainly divided into three categories: high temperature alumina, low temperature alumina and ρ-Al2O3.
1. γ series low temperature alumina
The product in this form is dehydrated at a temperature not exceeding 600°C. Contains ρ-alumina, χ-alumina, η-alumina, γ-alumina, but the crystallization is not good.
2. δ series high temperature alumina
This type of alumina is basically generated at a temperature between 800°C and 1000°C, and is called a molecular agent, including k-alumina, θ-alumina, and δ-alumina, it owns a better crystallized.
3. ρ-alumina
This activated alumina is an amorphous body, which is formed by rapid heating and dehydration of gibbsite. It has a very important characteristic: rehydration. According to its hydration characteristics, many different varieties of activated alumina products can be prepared.
ρ- Al2O3 +6H2O→Al2O3·H2O→Al2O3·3H2O
These transition-state aluminas are similar in chemical composition, but because of their different crystal structures, X-ray diffraction patterns are generally used to analyze characteristic peaks to distinguish varieties, and they can also be inferred from their origin and processing.