Silica Gel was patented in the Year 1919, but its usage became more prominent during World war II, for dehydrating the Pharmaceutical Supplies and is considered as a desiccant. The inclusion of Hygroscopic salts such as calcium chloride, perchlorates in Silica gel showed specific performance in Pharmaceutical applications. The Global competitive standards of Silica Gel to meet the Pharmaceutical applications are growing day by day because of their excellent absorption capacity at varying RH. As the relative humidity increases the adsorption capacity of the desiccant also increases. Therefore, it is most preferred in Analytical Techniques for Pharmaceutical preparations and purifications. Continue Reading->
A Component which is capable of absorbing moisture and water is essential in the field of exporting the things which are more susceptible to a slight increase in humidity. Silica Gel is such a component, made up of Sodium Silicate and acts as a desiccant or drier with microscopic pore size of 2.4 nanometers and a surface area of 700-800 square meters per gram which plays a main role in controlling humidity, as it has a high affinity to absorb water molecules from the surroundings. Also, Silica Gel has an infinite life because of its ability to absorb and Un-absorb the moisture; therefore it can be reconditioned and reused. Silica Gel is inert and has no volatile components.
Preservation in compressed air systems is attained only through Silica Gel desiccant. Since, Silica Gel has ability to convert from anhydrous state to hydrous state; it is doped with moisture indicators such as Methyl violet & Cobalt Chloride. Because of the impregnation of such indicators Silica Gel Desiccant exists in different colors, as a result of absorption of moisture and water.
Silica Gel can exist in both Silica Gel bead form, as well as Silica Gel crystal form. Silica Gel is a colorless solid, which is odorless and often interchangeable with silica xerogel which gives a granular form, which is purified and processed to attain Silica Gel bead form. To indicate the absorption of moisture, visually chemical indicators are impregnated in it, therefore various colored form of Silica Gel beads are available, depending on the absorption capacity of each. Blue Silica Gel crystals are developed by the coagulating the solution of silica acid. Silica Gel crystals are highly efficient, due to internal surface of about 800mz.
Silica Gel blue
Silica Gel on transfusion with Cobalt Chloride changes to Silica Gel blue in dry condition , but when becomes hydrated , it changes to Silica Gel Pink. It absorbs 5% of moisture and shows color variation depending on the absorption of moisture, i.e from blue to purple and to light red. Therefore, it is used as a desiccant in avoiding humidity damage. Silica gel Blue is also used as a Transformer breather as well as in Chemical Industries.
Silica Gel Orange
Since, Silica Gel blue was found to be hazardous and is presently replaced with Silica Gel Orange, with an alternative indicator methyl violet. In dry condition, Silica Gel orange remains in orange color, whereas changes its color to green when hydrated. It absorbs up to 2% of moisture and shows color variation depending on the absorption of moisture, i.e from light brown yellow to light brown green and then to blackish green. Therefore, it is used in the field of medicines, leather, and electrical appliances. Silica Gel orange is also used in Refrigeration and purification of power and air.
Silica Gel white
When Silica Gel is not transfused with and indicating agents, it exists in Silica Gel white form, which has an absorption of 5% of moisture and shows color variation depending on the absorption of moisture, i.e from white to semi transparent and then to non transparent. Therefore, it is used as a catalyst carrier, rust inhibitor and also as gas drier. Silica gel white is also used in Power industries as well as for drying of flowers and seeds.