Silica, also known as silica, scientific name precipitated hydrated silica. It is a high-tech inorganic fine chemical product, the main component is SiO2. The performance and appearance of carbon black are similar to the appearance of white highly dispersed amorphous powder or flocculent powder, and it is processed into granules as a commercial product. Light in weight, the relative density of the original particle size below 0.3μm is 2.319-2.653, and the melting point is 1750°C. It is insoluble in water and most acids, and will become water-absorbing fine particles when absorbed by water in the air. It is soluble in caustic soda and hydrofluoric acid. Other chemicals will not react, will not decompose at high temperature, and will not burn. It is chemically inert to substrates and active ingredients and additives, and has good compatibility with many active ingredients commonly used in vitamins, hormones, fluorides, antibiotics, enzyme preparations and cosmetics. Has high electrical insulation. Due to its porosity and large specific surface area, it has a large dispersing ability in raw rubber and shows high reinforcing properties in rubber. The surface modification of hydrophobic silica is easily dissolved in oil, rubber and plastic as a reinforcing filler, which will significantly improve its mechanical strength and tear resistance. Due to the different manufacturing methods, the physical and chemical properties of silica, and the micro-junction structure will have some differences, so the application fields and application effects are also different.

white carbon black is roughly divided into precipitation method white carbon black and gas phase method white carbon black according to the production method.

White carbon black is a general term for white powdery X-ray amorphous silicic acid and silicate products. It mainly refers to precipitated silica, fumed silica and ultrafine silica gel, and also includes powdered synthetic silicic acid. Aluminum and calcium silicate, etc.

white carbon black is roughly divided into precipitation method white carbon black and gas phase method white carbon black according to the production method. The vapor-phase white carbon black is white amorphous flocculent translucent solid colloidal nanoparticles (particle size less than 100nm) under normal conditions, non-toxic, and has a huge specific surface area. The fumed white carbon black is all nano-silica, the product purity can reach 99%, the particle size can reach 10-20nm, but the preparation process is complicated and expensive; the precipitation method is divided into traditional precipitation method white carbon black and Special precipitation method white carbon black, the former refers to silica produced with sulfuric acid, hydrochloric acid, CO2 and water glass as basic raw materials, and the latter refers to the use of supergravity technology, sol-gel method, chemical crystal method, and secondary crystallization Silica produced by special methods such as the reverse micellar microemulsion method or the reverse micellar microemulsion method. Precipitated silica is mainly used as a reinforcing agent for natural rubber and synthetic rubber, toothpaste friction agent, etc. Fumed silica is mainly used as a reinforcing agent for silicone rubber, as a thickener for coatings and unsaturated resins, while ultrafine silica gel and aerogel are mainly used as matting agents for coatings, thickeners, and plastic film opening agents.

Benefited from the increase in demand in the tire manufacturing, silicone rubber industry, coatings industry, new energy and other fields, it is expected that the average annual growth rate of my country's precipitation method silica (silica) demand will be about 10% in the future. In 2015, Asia will become a large market for highly dispersed silica, and its demand growth rate will be much higher than the global average growth rate of 9%, reaching 15% or higher. China accounts for 40% of the Asian market and will become the largest single market in the world.

What are the traditional methods for preparing white carbon black?

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

traditional method

(1) Gas phase method

is mainly chemical vapor deposition (CAV) method, also known as pyrolysis method, dry method or combustion method. The raw materials are generally silicon tetrachloride, oxygen (or air) and hydrogen, which are formed by the reaction at high temperature. The reaction formula is:

　　SiCl4+ 2H2+ O2—>SiO2+4HCl

Air and hydrogen are respectively pressurized, separated, cooled and dehydrated, silica gel dried, dust removed and filtered, and then sent to the synthesis hydrolysis furnace. After the silicon tetrachloride raw material is sent to the rectification tower for rectification, it is heated and evaporated in an evaporator, and the dried and filtered air is used as a carrier to send to the synthesis hydrolysis furnace. After silicon tetrachloride is vaporized at high temperature (flame temperature 1000~1800℃), it undergoes gas phase hydrolysis with a certain amount of hydrogen and oxygen (or air) at a high temperature of about 1800℃; the fumed silica particles generated at this time It is thin and forms aerosol with gas, which is not easy to capture, so it is first aggregated into larger particles in the agglomerator, and then collected by the cyclone separator, and then sent to the deacidification furnace, and the fumed silica is purged with nitrogen-containing air. The PH value is 4-6 is the finished product.　

(2) Precipitation method

The precipitation method is also called the sodium silicate acidification method, which uses a water glass solution to react with an acid, precipitation, filtration, washing, drying and calcination to obtain white carbon black. The reaction formula is:

　　Na2SiO3 + 2H+ —> white carbon black + 2Na+ + H20

Most domestic production enterprises adopt precipitation method.

white carbon black is roughly divided into precipitation method white carbon black and gas phase method white carbon black according to the production method.

White carbon black is a general term for white powdery X-ray amorphous silicic acid and silicate products. It mainly refers to precipitated silica, fumed silica and ultrafine silica gel, and also includes powdered synthetic silicic acid. Aluminum and calcium silicate, etc.

white carbon black is roughly divided into precipitation method white carbon black and gas phase method white carbon black according to the production method. The fumed silica is white amorphous flocculent under normal conditions

Transparent solid colloidal nanoparticles (particle size less than 100nm), non-toxic, with huge specific surface area. The fumed white carbon black is all nano-silica, the product purity can reach 99%, the particle size can reach 10-20nm, but the preparation process is complicated and expensive; the precipitation method is divided into traditional precipitation method white carbon black and Special precipitation method white carbon black, the former refers to silica produced with sulfuric acid, hydrochloric acid, CO2 and water glass as basic raw materials, and the latter refers to the use of supergravity technology, sol-gel method, chemical crystal method, and secondary crystallization Silica produced by special methods such as the reverse micellar microemulsion method or the reverse micellar microemulsion method. Precipitated silica is mainly used as a reinforcing agent for natural rubber and synthetic rubber, toothpaste friction agent, etc. Fumed silica is mainly used as a reinforcing agent for silicone rubber, as a thickener for coatings and unsaturated resins, while ultrafine silica gels and aerogels are mainly used as matting agents for coatings, thickeners, and plastic film opening agents.