Environmental Controls » Dust Collection Systems

Air and oxide flow diagram
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Flue gases from furnaces and air from ventilation systems are vented to cyclones, scrubbers, baghouses, etc. for particulate removal. Flue dust must be removed from the separator (air pollution control equipment) and transported to storage, recycle streams, or to off-plant receivers.  Dust collection systems can be a significant source of lead exposure if not properly operated, cleaned, and maintained.

Fig. 1. Dust collection system

Potential Sources of Exposure

  • Employees have a high potential of overexposure to lead dust during cleaning and maintenance of dust collection systems (cyclones and baghouses) (Fig. 1).

  • Employees have a high potential of overexposure to lead dust during handling and transporting of materials removed from dust collection systems (cyclones and baghouses).

  • Employees have a high potential overexposure to lead dust due to improperly maintained dust collection systems.

Possible Engineering & Work Practice Controls

  • Screw or pneumatically convey flue dust back to the process.
  • Provide vehicles with enclosed cabs that have positive-pressure, HEPA filtered air.

  • Enclose or cover containers used to transport lead from dust collection systems.

  • When working on or entering ventilation or dust-control equipment for maintenance or cleaning, implement proper permit required confined space entry and energy-control procedures.

  • Always provide appropriate personal protection equipment.

  • Ensure that dust-control equipment is designed, operated, and maintained properly on a scheduled basis to prevent breakdown and release of lead to the ambient environment.

Potential Sources of Exposure

  • Lead dust and fumes may be emitted from agglomeration flue gases that contain lead.

  • Lead fumes may be emitted at the slag tap, when pouring slag to the casting machine, during transfer of slag, or from cooling slag.

  • Lead dust may be emitted from disturbed settled particulate.

Possible Engineering & Work Practice Controls

Agglomeration furnace diagram

  • Provide local exhaust ventilation that controls lead emissions at the slag port, launder, and receiving kettles.

  • Enclose and exhaust ventilate the slag casting line and slag dumping station.

  • Provide two agglomerating furnaces.
  • Use enclosed screw conveyors to deliver dust to the furnace.

  • Provide curtains and baffles, if necessary, to prevent cross-drafts.

  • Ensure that access doors to agglomeration furnaces are closed.

  • Provide a swing-away section of the furnace flue to facilitate flue cleaning directly above the furnace.

  • Provide vehicles with enclosed cabs that have positive-pressure, HEPA filtered air.