White carbon black is a general term for fine powder or ultrafine particles of anhydrous and hydrous silica or silicates. It is a white, non-toxic, amorphous fine powder with a large SiO2 content (greater than 90). %). At present, there are two kinds of white carbon black on the market: gas phase white carbon black and precipitation white carbon black.

White carbon black is a general term for fine powder or ultrafine particles of anhydrous and hydrous silica or silicates. It is a white, non-toxic, amorphous fine powder with a large SiO2 content (greater than 90). %). At present, there are two kinds of white carbon black on the market: gas phase white carbon black and precipitation white carbon black. Precipitation silica (scientific name precipitated hydrated silica) is mainly used in footwear, tires and other light-colored rubber products. Other uses include use as a carrier or flow agent in pesticides, feed and other industries, and as a toothpaste. Friction agents are used as dispersants, anti-settling agents or matting agents in coatings. Vapor phase silica (scientific name: fumed silica) is a multifunctional additive. It is mainly used in the field of room temperature vulcanized silicone rubber (RTV) and heat vulcanized silicone rubber (HTV). Adhesives, inks, chemical machinery polishing, papermaking, food, and colloidal batteries can play a role in thickening, thixotropic, matting, and anti-settling.

The production method of fumed silica is mainly chemical vapor deposition (CAV). This process is also called pyrolysis, dry or combustion. In the preparation process, silicon tetrachloride (or methyltrichlorosilane) raw material is sent to a rectification column for distillation, and then heated and evaporated in an evaporator, and the dried and filtered air is used as a carrier to be sent to a synthetic hydrolysis furnace. . The advantages of the gas phase method are that the production process is relatively simple, the reaction conditions are easy to control, the product purity can be as high as 99.8%, the specific surface area is large, the activity is high, and the number of surface hydroxyl groups is low, which is suitable for the synthesis of high-purity silica. The adsorption of water and the preparation process lead to the appearance of acid regions on the surface, making the white carbon black hydrophilic, difficult to infiltrate and disperse in the organic phase, high production cost, expensive product, small application range and low yield. The specific operation control of the production process of gas phase silica is difficult, especially for the production of high grade products (products with high specific surface area). The technical difficulties are the three aspects of heat dissipation of the synthesis furnace, high-efficiency separator operation control, and hydrogen chloride desorption. The most difficult to control are the gas phase equilibrium and gas-solid phase equilibrium of the system. In terms of surface modification, large multinational corporations all adopt continuous dry surface modification technology, and they are all developing in the direction of high efficiency, energy saving and environmental protection. Domestic research in this area is still lagging behind.

The precipitation method is also called wet method, and the main raw materials are quartz sand, soda ash, industrial hydrochloric acid, sulfuric acid, nitric acid or carbon dioxide. The production process mainly includes the steps of precipitation, filtration, drying and granulation. Industrial water glass is prepared by reacting quartz sand with soda ash at high temperature using fuel oil or high-quality coal; industrial water glass is formulated with a certain concentration of dilute solution, and then under certain conditions, an acid is added to generate hydrated silica precipitate. According to the requirements of the finished product, it is filtered and washed in a roller filter press or a plate filter to remove excess water and reaction by-products to obtain a white carbon filter cake; and then dried (usually spray-dried) to obtain the finished product. If it is further ground or granulated, a series of specifications can be obtained.