What Is Black White Carbon

White carbon black is an inorganic compound in the form of white powder, granules or irregular blocks. Its main component is silicon dioxide, and its chemical expression is SiO₂・nH₂O. It is usually called precipitated hydrated silicon dioxide.
Physical and chemical properties
Physical properties: It appears as white powder, granules or irregular blocks, with a true density of about 2.0g/ml and a false density of about 0.2g/ml. It is resistant to high temperatures, non-combustible, has good electrical insulation, and has a large specific surface area. The specific surface area of ​​white carbon black for different purposes is different, generally between 145-300m²/g.
Chemical properties: It is chemically stable and insoluble in water and acid, except for hydrofluoric acid. It can react with caustic soda to form sodium silicate and water, and react with hydrofluoric acid to form silicon tetrafluoride and water.
Production method
Gas phase method: It is mainly chemical vapor deposition (CVD) method, also known as pyrolysis method, dry method or combustion method. The raw materials are generally silicon tetrachloride, oxygen (or air) and hydrogen, which react at high temperature. The fumed silica particles generated by the reaction are extremely fine and form aerosols with the gas. They need to be aggregated into larger particles in the aggregator first, then collected by the cyclone separator, and finally sent to the deacidification furnace, and washed with nitrogen-containing air until the pH value is 4-6 to obtain the finished product. The product purity can reach 99% and the particle size can reach 10-20nm, but the preparation process is complicated and expensive.
Precipitation method: also known as sodium silicate acidification method, which uses water glass solution to react with acid, and obtains white carbon black through precipitation, filtration, washing, drying and calcination. In addition, there are some special precipitation methods, such as the use of special methods such as supergravity technology, sol-gel method, chemical crystal method, secondary crystallization method or reverse micelle microemulsion method.
Main use
Rubber industry: It is a reinforcing agent for natural rubber and synthetic rubber, which can improve the mechanical properties of rubber such as tensile strength, tensile strength and elongation at break, and at the same time improve the heat resistance, wear resistance and tear resistance of rubber. It can replace carbon black for reinforcement in white or colored rubber products to meet the color requirements of the product.
Coating and paint industry: It can be used as a thickener and matting agent for coatings and unsaturated resins, which can adjust the viscosity and rheological properties of the coating, so that the coating has good construction performance and stability, and can also give the coating a matting effect, improving the texture and decorativeness of the coating.
Toothpaste industry: As a friction agent and thickener for toothpaste, it has good flexibility and dispersibility, can make the paste smooth, soft, and abrasive, does not abrade the toothpaste tube, and can also be well compatible with fluoride to avoid the disadvantages of calcium salt as an abrasive to produce insoluble salts.
Other fields: It is used as a paper filler in the papermaking industry to improve the paper's anti-ink penetration performance and mechanical strength, increase whiteness, and reduce unit weight; in agricultural chemicals, it can be used as a carrier or diluent, disintegrant for pesticides, high-efficiency spraying fertilizers, etc.; it is also widely used in electronic packaging materials, resin composite materials, plastics, medicine, cosmetics and other fields.