Silica gel (Silica gel, Silica) another name: Silica gel, is a highly active adsorption material, amorphous materials, the chemical formula for mSiO2 • nH2O. In addition to the strong alkali, hydrofluoric acid does not react with any material, insoluble in water and any solvents, avirulent insipidity, stable chemical properties. Silica gel is a kind of chemical raw materials.
Silica gel can be used as a desiccant, and can be repeated use. Silica gel is made of silica gel mSiO2 • nH2O dehydration and appropriate particle size different porous material. With open porous structure, specific surface (surface area of unit mass) is very big, can absorb a lot of material, is a kind of very good desiccant, adsorbent and catalyst carrier. Silica gel adsorption is mainly physical adsorption, can be recycled and repeatedly used. Adding acid to alkali metal silicate, such as sodium silicate solution, acidification, stir and add a certain amount of electrolyte, namely generate silicate gel; Or in the concentration of sodium silicate solution adding acid or ammonium salt can also generate silicate gel. Silicic acid congealed gel will rest for a few hours of aging, then wash with hot water soluble salts, under 60 ~ 70 ℃ drying and activation when about 300 ℃, can get the silicone. Silica gel with cobalt chloride solution after soaking and drying and activation, available color silica gel. Use it as a desiccant, before the water is blue, the water absorption after getting red, can be seen from the change of the color degree of water absorption, and whether to need to deal with the regeneration. Silicone is widely used in steam recycling, oil refining and the preparation of catalyst, etc.