Refining, Densification, And Granulation Of Carbon Black

Carbon black contains a small amount of solid pollutants such as coke particles, hard slag, refractory debris, and rust. The most effective equipment for removing solid pollutants is a hard slag separator, which utilizes the different settling rates of carbon black and solid pollutants for separation. Using a rotating body to generate high centrifugal force, adjusting the speed of the rotating body and the amount of auxiliary air, effectively separating the hard slag in carbon black within a wide range. The solid pollutants in carbon black are crushed to below 325 meshes with a micron grinder, so as not to affect the application in rubber products. Separate ferromagnetic pollutants in the form of rust or metal abrasives using an automatic cleaning magnetic separator. However, in order to reduce the possibility of rust formation, Delong Carbon Black Plant used stainless steel and other rust resistant material equipment.
Carbon black densification
The loose carbon black separated from the micron pulverizer after air delivery contains considerable gas, and the density is very small (40~50kg/m ³）， Therefore, further densification is necessary before being sold as a product. The degree and method of densification depend on the use of carbon black.
Install a stirrer in the powdered carbon black storage tank. Its slow stirring plays a primary densification role, and ensures that a certain flow of carbon black enters the subsequent densification process through the adjustable airtight valve under the mixer. In order to achieve stable production, it is necessary to maintain a balance between the carbon black entering the powder tank and the carbon black discharged. It is achieved by using the level gauge or electronic scale of the powder tank as the parameter and adjusting the rotation of the airtight valve.
The most common form of densification for powdered carbon black is vacuum densification. Carbon black passes through a drum with multiple micropores and can be filtered through. The drum is vacuumed, and there is also a drum parallel to the permeable filter drum with a certain gap. The two drums rotate relative to each other, and the carbon black achieves densification effect through the drum. For pigment carbon black that is easily dispersed in powder form, this method is mainly used for densification.
Carbon black granulation
Higher carbon black densification is obtained through granulation. There are two forms of carbon black granulation: dry granulation and wet granulation.
Dry granulation is the process of continuously passing carbon black through a rotating cylinder, causing powdered carbon black to become spherical particles due to its physical adhesion. The dry granulation equipment is simple, the granulation cost is low, and the energy consumption is low. However, the particle strength is low, and the particles are easily damaged during bulk transportation, which is not conducive to the pneumatic transportation, sickle storage, and internal mixer feeding of carbon black in rubber plants. Dry granulation, the higher the carbon black structure, the more difficult it is to granulation. Reflux particle carbon black in a certain proportion as a "seed" and granulation together with newly added powder to improve granulation ability.