Silica and Desiccant

Desiccant

Indicating molecular sieve. Indicating molecular sieve provides a higher capacity for water adsorption than silica gel at lower humidity levels while providing a similar indicating element. While the indicator granules are blue, the desiccant is in an active state. 

As the indicator beads become a lighter shade of blue, the desiccant is approximately 60% saturated.  When the indicator beads become beige, the desiccant has reached equilibrium capacity and should be replaced.

Silica gel is a silicon dioxide (SiO₂), an amorphous form of silica which is manufactured from silicate and sulfuric acid. It is a naturally occurring mineral that is purified and processed into beaded or granular form and is also non-corrosive and chemically inert.

Much like a sponge, silica gel’s interconnected pores form a vast surface area that will attract and hold water by adsorption and capillary condensation, enabling silica gel to absorb about 40% of its weight in vapor at 100 percent humidness.

As a chemical agent, silica gel has an average pore size of 24 angstroms (24A). Silica gel desiccant will pull in moisture at temperatures up to 150°F (65°C). As temperatures increase on top of 100°F (38°C), the rate of moisture pick-up will slow down, but the silica gel will still work. Silica gel performs best at room temperature between 70°F to 90°F (21°C to 32°C) and at high humidity between 60% to 90% relative humidity.

Indicating silica gel can be used as a primary desiccant or blended with other desiccants in any application where control of moisture is required, such as:

• compressed air dryers;
• gas drying breathers;
• protection of non-consumable packaged goods;
• drying and storage of vegetable seeds and flower seeds, etc. 

Indicating colloid mustn't be utilized in contact with a product meant for consumption, like food or prescribed drugs. It is very useful to keep products as dry.