How is powdered white carbon black processed into granular form?

Dry granulation and wet granulation produce granular white carbon black with certain differences in properties such as density, strength, specific surface area, and dispersibility, as detailed below:

Density

Dry Granulation:
In the dry granulation process, powdered white carbon black is primarily compressed and aggregated through mechanical pressure, resulting in relatively larger voids between particles. Therefore, the bulk density of granular precipitated silica produced by dry granulation is generally lower.

Wet Granulation:
In wet granulation, the involvement of a liquid medium allows white carbon black particles to bond more tightly under the action of binders or solutions. After drying, the internal and inter-particle structures become more compact, leading to a higher bulk density of the fumed silica granular white carbon black produced by this method.

Strength

Dry Granulation:
Dry granulation relies mainly on mechanical forces to aggregate powder particles. The binding forces between particles are relatively weak, such as van der Waals forces, along with mechanical interlocking formed by particle compression. As a result, the overall particle strength is relatively low, making the particles more prone to breakage and pulverization during transportation, storage, and use.

Wet Granulation:
In wet granulation, binders play a crucial role in bridging particles during the formation process. They form a thin film on the surface of white carbon black particles, firmly bonding them together. This results in higher strength and hardness, making the particles more resistant to breakage and pulverization under external forces such as friction and impact.

Specific Surface Area

Dry Granulation:
Dry granulation causes relatively little damage to the original structure of powdered white carbon black. The internal and surface pores and irregular structures are largely retained, resulting in a relatively larger specific surface area. This provides an advantage in applications requiring high adsorption performance and surface activity.

Wet Granulation:
In wet granulation, white carbon black particles undergo re-agglomeration and shaping in a liquid environment, leading to smoother surfaces and fewer pore structures. This typically results in a smaller specific surface area compared to products from dry granulation.

Dispersibility

Dry Granulation:
Granules produced by dry granulation may have irregular shapes and higher surface roughness, which can lead to poorer dispersibility in certain media. Especially in high-viscosity systems, particles are more prone to agglomeration, requiring stronger stirring or dispersion measures to achieve uniform distribution.

Wet Granulation:
Granules produced by wet granulation usually have better sphericity and surface smoothness, resulting in superior dispersibility in various media. They can distribute more evenly in matrix materials, contributing to improved performance stability of the final product.