Silica gel is the most commonly used desiccant for providing efficient climatic protection. It is basically a refined form of silica which is produced by the reaction of a mineral acid, usually sulphuric, and a sodium silicate solution. This produces a highly porous structure which is capable of adsorbing up to approximately 30% of its own weight of water from the surrounding atmosphere at 50% RH and 25°C. The adsorption up to 50% RH is almost a linear relationship between the percentage water uptake and the equilibrium relative humidity.
Silica gel is produced in granular and beaded forms. Beaded silica gel has a higher mechanical strength than the granular form and therefore less likely to generate dust. Also, the uniform bead size reduces gas flow channelling and minimizes pressure drop.
Silica gel may be reactivated for re-use by heating. However, after several reactivation cycles the material may disintegrate into powder. This in turn, reduces the adsorption capacity of the material. Please contact us for the specific reactivation procedure.
The adsorption capacity of silica gel can be destroyed by contamination with dust, grease or petroleum products, and also by heating the material above 120°C.