White carbon black

White carbon black

Chinese aliases
Silica (combustion method); gas phase silica; granulated silica; medicinal grade silica; GH-7 silica; GH-1A silica; GH-1B silica; hydrated silica; white carbon black; white smoke; precipitated hydrated silica; pure latex; colloidal silica; precipitated silica;
English name
White carbon black
English aliases
white carbon;White carbon black,combustion method;Pelleted Hydrated Silica;Hydrated Silica;Silicondioxidehydrate;Silica, hydrate;SILICA;Precipitated silica;
EINECS Number：238-878-4
Molecular formula：SiO2.x(H2O)
Physicochemical properties:
Melting point 1610 °C(lit.)
Boiling point >100 °C(lit.)
Density 2.6 g/mL at 25 °C(lit.)
Refractive index n20/D 1.544(lit.)
Storage conditions 2-8°C
form tablets (~0.5 g each)

Component
　　Silica is generally divided into precipitation silica and gas phase silica according to production methods. White amorphous flocculent half of fumed silica under normal conditions.

　　Transparent solid colloidal nanoparticles (particle size less than 100 nm) are non-toxic and have large specific surface area. Fumed silica is all nano-silica with purity of 99% and particle size of 10-20 nm, but its preparation process is complex and expensive. Precipitation silica can be divided into traditional precipitation silica and special precipitation silica. The former refers to silica produced with sulfuric acid, hydrochloric acid, CO2 and sodium silicate as basic materials. The latter refers to silicon dioxide produced by special methods such as high gravity technology, sol-gel method, chemical crystal method, two crystallization method or reverse micelle microemulsion method. Precipitated silica is mainly used as reinforcing agent and toothpaste friction agent for natural rubber and synthetic rubber. Fumed silica is mainly used as reinforcing agent, coating and unsaturated resin thickener for silicone rubber. Ultrafine silica gel and aerogel are mainly used as paint matting agents, thickening agents, plastic film openings, etc.

Preparation
　　The traditional method of preparing silica is to use sodium silicate, silicon tetrachloride and ethyl orthosilicate as silicon sources. Except sodium silicate, other costs are very high. The new method uses cheap non-metallic ore as silicon source, which greatly reduces the production cost of silica.

Purpose
　　Because of a series of advantages of silica products, it can be widely used in many fields.

Rubber products
　　Silica is used in color rubber products to replace carbon black for reinforcement to meet the needs of white or translucent products. Silica has super adhesion, tear resistance, heat resistance and aging resistance, so it can replace some carbon black in black rubber products to obtain high quality rubber products, such as off-road tires, engineering tires, radial tires, etc.

Agricultural Chemicals
　　In agricultural chemicals, such as pesticides, high-efficiency fertilizers and so on, the use of silica as a carrier or diluent can maintain a lasting effect, because it has high adsorption capacity, easy suspension, good affinity and chemical stability. Even in rainwater, washing and hot conditions, it can remain unchanged for a long time.

Daily chemical products
　　The transparent color and opaque toothpaste with silica as filler and abrasive agent has good flexibility, dispersibility, smooth, soft, good abrasion, and does not abrasion the tube of toothpaste; it can keep the stability of medicinal toothpaste. Especially, it has good compatibility with fluoride, which can avoid the disadvantage of insoluble salt produced by calcium salt as abrasive.

Cementing agent
　　Thixotropy and reinforcing properties are provided in the adhesives made of natural rubber or synthetic rubber. At the same time, because of its extensibility, it can also improve the adhesion force, high quality and low price.

Anticaking agent
　　Silica can be used in a number of products to improve free mobility, such as grassland fertilizers, fungicides, grinding wheel abrasives, laundry bleaching agents, phenolic injection of urotropine, phenol and urea plastic products, the manufacture of rubber sulfur and anti-caking mixtures.

Paper filler
　　Using silica as paper filler can improve the ink resistance and mechanical strength of paper, increase whiteness and reduce unit weight. It can effectively realize paper lightweight, reduce production costs and improve paper performance.
　　In addition, it can also be used in many industries, such as firefighting agents, feed, cosmetics, extinction agents, pigments, paints and so on.