The following factors should be considered while handling carbon black dust:
In my experience, fine carbon black dust is an explosible/combustible material. If you are unsure whether the grade of carbon black dust that you are handling/processing is explosive or not, consider conducting an explosibility screening test (Go/No Go test) on a representative sample of the carbon black.
If the dust is found to be explosive, minimize the spread of the dust cloud by the provision of an effective local exhaust ventilation, prevent the accumulation of dust on the outside surface of the equipment and in the room by adapting an effective housekeeping procedures, and control potential ignition sources.
Ways to control potential ignition sources include: ensuring that all metal sections of the bag dump station are bonded together and grounded; conducting a hazardous area classification to ensure the use of appropriate electrical equipment; preventing foreign objects from entering the screw conveyor; maintaining the mechanical (moving) parts of the system to prevent their failure. Additionally, if the Minimum Ignition Energy (MIE) of the dust cloud is less than about 30mJ, the operator(s) handling the dust must be grounded. Also, protect processing equipment such as receiving vessel(s) and dust collector(s) against the consequences of an explosion by the provision of appropriate protection systems (e.g. explosion relief vents).
Also, seek expert advice on identification, assessment, and control of potential dust cloud explosion hazards.