Silica gel is solid organic amorphous material characterized by its high surface area that gives its high moisture adsorption capacity. It is produced from sodium silicate in the form of beaded, having presence of small spherical, and granular, having hard irregular crystals appearance.
The water molecules adhere to the surface area of silica gel because it exhibits a lower vapor pressure than the surrounding air. Once an equilibrium pressure is reached, no more adsorption process occur. Thus, the greater the humidity levels (above 50% relative humidity) the higher the water portion that is adsorbed before an equilibrium is reached.
Types of Silica Gel
Blue Silica Gel: The most common use of cobalt chloride blue gel available in beaded & granular form. It used as an indicating agent when it is free from moisture its color changes to light pink. Most of the transformer industries prefer this silica gel for large transformer breather process.
Orange Silica Gel: It is the organic gel to indicate the moisture absorption level, available in the form of hard spherical beads & when it takes up whole moisture level its color changes to green. Orange beads are heavy metal free, environment-friendly gel desiccant for packaging products protection and miscellaneous substances. It has extremely resistance to crushing, highest mechanical integrity and low attrition rate. Silica Gel orange MSDS meets the demand for a heavy metal free and environmental friendly indicating agent.
White Silica Gel: It is non-indicating gel which is not impregnated with any indicating agents. When white gel particles free from moisture, it goes transparent white or turns into milky white. White silica gel is mostly used for dehumidification process.
Regeneration of Silica Gel
Once silica gel saturated with water, the indicating gel can be regenerate by heating it to 100120 0C for 12 hours. When it completely regenerated, they return to its original color and its dry weight.