More than your standard desiccant, activated alumina is known for its ability to effectively dry and purify liquids and gases.
Activated alumina is a type of desiccant that is commonly used to remove moisture and impurities from gases and liquids. It is made from aluminum oxide (Al2O3), which is heated to produce a highly porous material.
Broadly, AGM recommends activated alumina desiccant in cyclical applications, such as when a desiccant is repeatedly saturated and regenerated. Use in regenerative dryers is a common example. Gas separation is another frequent application of activated alumina; however, the desiccant has many varied uses, including:
The amount of water that activated alumina will adsorb before it becomes saturated will depend on various factors such as the surface area of the material, the pore size, the relative humidity of the surrounding environment, and the temperature. However, activated alumina typically adsorbs less water than silica gel and molecular sieve.
Broadly speaking, activated alumina can adsorb up to approximately 20% of its weight in water. However, this varies depending on the specific type of activated alumina and the conditions of use.
It’s also important to note that desiccant-load replacement is commonly prescribed for when the relative humidity of a desiccated environment reaches some chosen threshold. Desiccant amounts and types for a given application are calculated based on the demands of a system; therefore, once the RH of that system begins to rise, it may be surmised that the desiccant is saturating or has saturated to a point of inefficiency.
Further, once desiccant becomes saturated, it will no longer be effective at adsorbing moisture. Therefore, it's important to monitor the saturation level of the activated alumina or monitor the RH of the enclosure, and replace the desiccant or regenerate it as needed to ensure that it continues to be effective. This is frequently done using a humidity indicator card.
For information about other kinds of desiccants, check out AGM's desiccant guides.
Activated alumina is generally considered non-toxic, as it is an inert material that does not react with most chemicals. However, as with any material, there may be some risks associated with exposure to activated alumina, particularly if it is inhaled as dust or ingested in large quantities.
As with all of the bulk desiccants that AGM markets, it’s recommended to store activated alumina in metal cans at room temperature (60°F – 80°F or 15°C – 26°C) with humidity between 0% and 70% RH.
AGM guarantees shelf life up to 1-year for all desiccants it markets, provided the desiccant is kept in uncompromised, original packaging, and stored in optimal conditions. If you need greater shelf life, contact AGM.
Check out AGM’s Desiccant Unit Calculator for a broad understanding of how many units of a particular desiccant a project needs based on the volume of space in need of protection. Additionally, try AGM’s Humidity Calculator to get a better sense of your project’s environment. When used together, the two calculators provide a broad level idea of your protection needs.
For projects with high sensitivity that require precision solutions, contact AGM and speak with an engineer. AGM’s expertise in adsorbents has continued to safeguard the aerospace industry since 1970.
The equipment and processes used to manufacture activated alumina are expensive and potentially hazardous. As such, AGM does not recommend attempting to make the desiccant by anyone other than qualified persons. Therefore, the process described below for making activated alumina desiccant is intended for informational purposes only and may not be complete.
AGM has supplied desiccants to industries across the globe since 1970. Our engineering department regularly consults with industry engineers to design and manufacture custom solutions for highly sensitive and complex projects, such as aerial optics, large- and small-launch rocket fuel tanks, and much more.
For help protecting your project, contact AGM engineers today.
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