Name: silica gel
Alias: silica gel or silicic acid gel
English name: Silica? Gel; ? silicon dioxide
Molecular formula: xSiO2 yH2O
Molecular weight: 60.08
CAS？ Login number: CAS#? 1 12926-00-8
EINECS？ Login number: 23 1-545-4
Generally speaking, silica gel can be divided into organic silica gel and inorganic silica gel according to its nature and composition.
Inorganic silica gel uses:
Silica gel can be used as a desiccant and can be reused. Silica gel is a porous substance with different particle sizes, which is properly dehydrated from silicic acid gel mSiO2 nH2O. It has an open porous structure and a large specific surface area (surface area per unit mass), and can adsorb a variety of substances. It is a good desiccant, adsorbent and catalyst carrier. The adsorption of silica gel is mainly physical adsorption, which can be regenerated and reused. ? Adding acid into alkali metal silicate (such as sodium silicate) solution to acidify it, then adding a certain amount of electrolyte and stirring to generate silicic acid gel; Or adding acid or ammonium salt to concentrated sodium silicate solution can also form silicic acid gel. The silicic acid gel was allowed to stand for several hours to age, then the soluble salt was washed away with hot water, dried at 60 ~ 70℃, and activated at about 300℃ to obtain silica gel. ? The color-changing silica gel can be obtained by soaking silicic acid gel in cobalt chloride solution, drying and activating. When used as a desiccant, it is blue before absorbing water and turns red after absorbing water. From the change of color, we can see the degree of water absorption and whether it needs regeneration treatment. Silica gel is also widely used in steam recovery, petroleum refining and catalyst preparation. Silicone can also be used as a mobile phone case, which is extremely resistant to falling.
Use of silicone
Because of these excellent properties, silicone has a wide range of applications. It is not only used as a special material for aviation, cutting-edge technology and military technology departments, but also used in various departments of the national economy. Its application scope has been extended to: architecture, electronics and electricity, textiles, automobiles, machinery, leather and paper, chemical industry and light industry, metals and coatings, medicine and medical treatment.