Silica gel is a kind of highly active adsorption material, is an amorphous substance, which contains polysiloxane, silicon oil, white carbon black (silica), coupling agent and filler, etc., the main component is silica, its chemical formula is MSiO2 ·nH2O. Insoluble in water and any solvent, non-toxic and tasteless, stable chemical properties, in addition to strong alkali, hydrofluoric acid does not react with any substances. Various types of silica gel due to its different manufacturing methods and the formation of different microporous structure. The chemical composition and physical structure of silica gel determine that it has many characteristics that are difficult to be replaced by other similar materials: high adsorption performance, good thermal stability, chemical stability, high mechanical strength and so on.

  Classification of silica gel: silica gel according to its vulcanization characteristics can be divided into hot vulcanized silicone rubber and room temperature vulcanized silicone rubber two categories. According to the different performance and use can be divided into general, super low temperature resistance, super high temperature resistance, high strength type, oil resistance, medical type and so on. According to the different monomers, it can be divided into methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber, fluorosilicate, nitrile silicone rubber and so on.