Aerogel preparation patent

To precipitate silicon dioxide, the specific process is complicated, such as increasing the reaction temperature, or adding template agents such as polyethylene glycol and polyvinyl alcohol, as well as three-stage heating method. It is suggested to search for precipitated silica in Baidu patent to view relevant information.

The main raw materials for producing aerogel silica are sodium silicate and sulfuric acid.

1. Firstly, sodium silicate solution and dilute sulfuric acid solution with a certain concentration are prepared as required.

2. Mix the prepared two solutions and pass through the reactor for mixing reaction.

3. Preparation of silica gel.

Extended data:

Hydrofluoric acid reacts with silicon dioxide to produce gaseous silicon tetrafluoride. React with hot concentrated alkali solution or molten alkali to form silicate and water. React with various metal oxides at high temperature to form silicates. Silicon dioxide is inactive, and does not react with halogen, hydrogen halide, sulfuric acid, nitric acid and perchloric acid except fluorine and hydrogen fluoride (except hot concentrated phosphoric acid).

Common concentrated phosphoric acid (or pyrophosphoric acid) can corrode silicon dioxide to form heteropoly acid at high temperature, and molten borate or boric anhydride can also corrode silicon dioxide at high temperature. In view of this property, borate can be used as a flux in ceramic firing, and hydrogen fluoride can also be an acid, which can dissolve silicon dioxide and generate water-soluble fluorosilicic acid.

Baidu encyclopedia-silicon dioxide