What are the production processes of silica gel desiccant?

What are the production processes of silica gel desiccant? The raw materials required for preparation include sodium silicate (sodium silicate, sodium silicate) and sulfuric acid.

1、 Prepare the alkali and acid in advance, then melt the solid sodium silicate with high temperature and filter it to prepare a liquid with a certain concentration, and then prepare a liquid with a certain concentration of sulfuric acid. The concentration of sulfuric acid is 20%.

2、 The second step is gel preparation (gel granulation), which is the most critical step. The prepared lye and sulfuric acid solution are reacted under specific conditions to form a gel soluble solution, which will become gel particles after reaching an appropriate concentration The shape and size of particles can be completely determined according to the user's needs and production capacity At present, the common method of gel granulation is Wei air granulation. The acid-base ratio, concentration, temperature and gel granulation time of gel are the specific process parameters of gel granulation process.

3、 The aging gel can be aged only after a certain time, temperature and pH value, which makes the gel skeleton strong. During the aging process, the glue between particles condenses to form Si-O-Si bonds, which enhances the strength of the skeleton. The particles approach each other, narrow the space in the grid structure, and extrude the water contained therein.

The fourth step is pickling, water washing and glue washing

Acid washing, water washing and glue washing are also very important steps in the process, because Na2SO4 formed by granular gel is washed to control the cation and anion ions within the range of process requirements.

It can be said that the pore characteristics of the finished silica gel are largely determined by the aging of the gel washing process, and the aging degree of this process depends on the manipulation in the pickling, water washing and gel washing processes

5、 Desiccant: put the prepared hydrogel (after washing) into the drying room, and reduce the water content of the gel itself to the required range under specific conditions. The higher the drying temperature is, the faster the primary particles gather and the larger the pore diameter is.

6、 Screening: the silica gel prepared after drying is screened out by a ball sorter through a sieve mesh with an approximate aperture according to a certain particle size, and the crushed silica gel is screened out at the same time.

7、 Glue picking: pick out the heterochromatic balls and impurities in the silica gel, then pack them with composite paper as required, and then seal them.

In this way, our moisture absorbing beads (silica gel desiccant) are even produced!