Thermal Stability of Activated Alumina
Briefly describe the thermal stability of activated alumina.
Thermal Stability of Activated Alumina
The thermal stability of activated alumina refers to its ability to maintain its structure and adsorption properties at high temperatures, and is a key indicator for evaluating its service life.
Factors Affecting Thermal Stability
Factors | Effect |
Preparation Process | Rapid stripping method produces products with fine grains and better thermal stability. |
Impurity Content | Alkali metals such as Na₂O accelerate phase transformation. |
Additives | Rare earth elements such as La and Ce can inhibit transformation and improve stability. |
Different types of thermal stability
Type | Stable Temperature Upper Limit | Applicable Scenarios |
Ordinary Activated Alumina | 600-700℃ | Drying, Adsorption (Regeneration Temperature 170-300℃) |
High-Purity Activated Alumina | 800-900℃ | High-Temperature Catalytic Support |
Rare Earth Modified Type | 900-1000℃ | Automotive Exhaust Purification, Petroleum Hydrogenation |
High-Temperature Resistant Special Type | 1000-1100℃ | High-Temperature Flue Gas Treatment |
Thermal Stability Requirements in Applications
Dry Adsorption (Regeneration Temperature 170-300℃): Ordinary products are sufficient; thermal stability is not an issue.
Catalyst Support (500-900℃): High-purity or rare-earth modified products are required.
High-Temperature Flue Gas Treatment (800-1000℃): High-temperature resistant specialized products must be selected.
Summary
The thermal stability of activated alumina is determined by its crystal phase transformation temperature and impurity content. Ordinary products are suitable for operating conditions below 600℃; high-temperature applications require high-purity or rare-earth modified products. When selecting a product, the appropriate type should be matched to the actual operating temperature to avoid performance degradation due to thermal deactivation.