Handling of Pigment Blacks

Much progress has been achieved in the past few years in the handling and transport of bulk products. The high risk of soiling, especially in the case of pigment blacks, is only one reason for underlining the importance of using closed systems.

Pigment Black is marketed as a powder and in beaded form. The technology available for handling them varies widely in some cases.

Depending on their specific composition, powdered carbon blacks can be fluidized more or less easily. This means that they can be conveyed over more or less long distances with pneumatic systems that use high air quantities and velocities. Conveyor screws are also used for shorter distances.

Powdered carbon blacks are shipped only in sacks or FIBCs (Flexible Intermediate Bulk Container) and not in rigid containers or silos. This is due mainly to their inadequate flow properties.

Flow characteristics and transportation properties of beaded carbon blacks are a lot better. However, great care is necessary to ensure that the beaded product is not damaged in transit. As beads get damaged, flow and transportation become increasingly difficult, which makes handling unnecessarily complicated and may contribute to machine downtime. That is one of the reasons why conveyor belts and bucket elevators are still in use today. Only dense phase conveying systems should be used in pneumatic facilities.

It is important to note that wet beaded carbon black with binding agents is characterized by a greater bead hardness than dry or oil-beaded carbon black. Depending on the bead hardness, even dense phase transportation systems may lead to bead decomposition in transit. Pneumatic dune and blow systems are not appropriate for beaded carbon blacks. Conveyor screws, gutters or vibration pipes are also common for shorter distances.

In case you have further queries, please contact our handling specialist:

AS-FA-AE/AT
Thomas Riedemann
Phone: +49-61 81-59-31 08
E-Mail: thomas.riedemann@degussa.com